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Default Pneumatic rack and pinion drive

I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that
would engage the round gear. No, I won't do it with a servo! I'm thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in
the middle of the tube to expose teeth to the round gear. This seems simple and
cheap. In fact, it's so simple it would seem that it should be an off-the-shelf
item! I just assume it would be easier to do with round rack than square rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will have an
adjustable stop to get my 80 to 100 degrees rotation. The round gear will have
a one-way clutch installed because I only want the one direction of shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of
wire.


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Default Pneumatic rack and pinion drive

Tom Gardner wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms.


(...)

Are you converting from linear to rotary to linear motion?
How about just an overrruning clutch and pinch roller mounted on the end of your
air cylinder shaft? Less mass. Fewer parts. Cheaper.

--Winston
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Default Pneumatic rack and pinion drive

On Jun 25, 10:37*pm, "Tom Gardner"
wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. *I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that
would engage the round gear. *No, I won't do it with a servo! *I'm thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in
the middle of the tube to expose teeth to the round gear. *This seems simple and
cheap. *In fact, it's so simple it would seem that it should be an off-the-shelf
item! *I just assume it would be easier to do with round rack than square rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will have an
adjustable stop to get my 80 to 100 degrees rotation. *The round gear will have
a one-way clutch installed because I only want the one direction of shaft
rotation. *The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of
wire.


They make pneumatic rotary actuators to do exactly what you want, turn
a shaft through a partial revolution and back. Kind of like a super-
sized version of the old vacuum windshield wiper motor, uses a vane in
a chamber driven by pressure, not vacuum. Might explain why you don't
see a geared actuator like you describe. Unless you've got a lot of
scrap parts laying around, might be the cheaper way to go!

Stan
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Default Pneumatic rack and pinion drive

On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote:

On Jun 25, 10:37*pm, "Tom Gardner"
wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. *I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that
would engage the round gear. *No, I won't do it with a servo! *I'm thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in
the middle of the tube to expose teeth to the round gear. *This seems simple and
cheap. *In fact, it's so simple it would seem that it should be an off-the-shelf
item! *I just assume it would be easier to do with round rack than square rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will have an
adjustable stop to get my 80 to 100 degrees rotation. *The round gear will have
a one-way clutch installed because I only want the one direction of shaft
rotation. *The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of
wire.


They make pneumatic rotary actuators to do exactly what you want, turn
a shaft through a partial revolution and back. Kind of like a super-
sized version of the old vacuum windshield wiper motor, uses a vane in
a chamber driven by pressure, not vacuum. Might explain why you don't
see a geared actuator like you describe. Unless you've got a lot of
scrap parts laying around, might be the cheaper way to go!

Stan



I thought I sent one of those to Tom already?

Gunner
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Default Pneumatic rack and pinion drive

For only about 90 degrees of motion you don't need the rack. just use the
crank shaft - connecting rod rod type idea. That is, an air cylinder
connected to a shaft with a lever arm. A short lever arm makes for very fast
motion, less torque.

Karl




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Default Pneumatic rack and pinion drive


Tom Gardner wrote:

I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that
would engage the round gear. No, I won't do it with a servo! I'm thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in
the middle of the tube to expose teeth to the round gear. This seems simple and
cheap. In fact, it's so simple it would seem that it should be an off-the-shelf
item! I just assume it would be easier to do with round rack than square rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will have an
adjustable stop to get my 80 to 100 degrees rotation. The round gear will have
a one-way clutch installed because I only want the one direction of shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of
wire.


Just search "rotary actuator" on mcmaster.com.
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Default Pneumatic rack and pinion drive

On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner"
wrote:

I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that
would engage the round gear. No, I won't do it with a servo! I'm thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in
the middle of the tube to expose teeth to the round gear. This seems simple and
cheap. In fact, it's so simple it would seem that it should be an off-the-shelf
item! I just assume it would be easier to do with round rack than square rack.
Is this available or did I invent a new wheel?


I've seen a mechanism like that; my friend Jim invented it to swing
the head on a die cutting machine in order to nest the cuts and save
material. The guy who invented the rack-type rotary actuator invented
it before him. Jim had cam followers supporting the rack where it
meshed with the gear.


The gear would just spin back and forth and the air cylinder/rack will have an
adjustable stop to get my 80 to 100 degrees rotation. The round gear will have
a one-way clutch installed because I only want the one direction of shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of
wire.


100ms is pretty fast for an air cylinder which, in this setup, will
probably never stop accelerating 'til it hits the endstop . Make sure
you install bumpers or hydraulic shocks (Ace, Enidine) at the ends of
the stroke.

Presumably there's enough friction in the wire feed to prevent
excessive overrun when the gear slams to a stop.

--
Ned Simmons
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"Winston" wrote in message
news:mnF8k.42$4J.20@trnddc05...
Tom Gardner wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms.


(...)

Are you converting from linear to rotary to linear motion?
How about just an overrruning clutch and pinch roller mounted on the end of
your
air cylinder shaft? Less mass. Fewer parts. Cheaper.

--Winston


You have amazing vision, that's exactly what I want to replace, it's not
tolerant of hard/soft/dry/oily wire.


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Default Pneumatic rack and pinion drive


"Gunner" wrote in message
...
On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote:

On Jun 25, 10:37 pm, "Tom Gardner"
wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear
that
would engage the round gear. No, I won't do it with a servo! I'm thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a scallop
cut in
the middle of the tube to expose teeth to the round gear. This seems simple
and
cheap. In fact, it's so simple it would seem that it should be an
off-the-shelf
item! I just assume it would be easier to do with round rack than square
rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will have
an
adjustable stop to get my 80 to 100 degrees rotation. The round gear will
have
a one-way clutch installed because I only want the one direction of shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of
wire.


They make pneumatic rotary actuators to do exactly what you want, turn
a shaft through a partial revolution and back. Kind of like a super-
sized version of the old vacuum windshield wiper motor, uses a vane in
a chamber driven by pressure, not vacuum. Might explain why you don't
see a geared actuator like you describe. Unless you've got a lot of
scrap parts laying around, might be the cheaper way to go!

Stan



I thought I sent one of those to Tom already?

Gunner


I didn't see it, I'd be interested in purchasing one if you still have one!


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Default Pneumatic rack and pinion drive


"Ned Simmons" wrote in message
...
On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner"
wrote:

I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear
that
would engage the round gear. No, I won't do it with a servo! I'm thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut
in
the middle of the tube to expose teeth to the round gear. This seems simple
and
cheap. In fact, it's so simple it would seem that it should be an
off-the-shelf
item! I just assume it would be easier to do with round rack than square
rack.
Is this available or did I invent a new wheel?


I've seen a mechanism like that; my friend Jim invented it to swing
the head on a die cutting machine in order to nest the cuts and save
material. The guy who invented the rack-type rotary actuator invented
it before him. Jim had cam followers supporting the rack where it
meshed with the gear.


The gear would just spin back and forth and the air cylinder/rack will have an
adjustable stop to get my 80 to 100 degrees rotation. The round gear will
have
a one-way clutch installed because I only want the one direction of shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of
wire.


100ms is pretty fast for an air cylinder which, in this setup, will
probably never stop accelerating 'til it hits the endstop . Make sure
you install bumpers or hydraulic shocks (Ace, Enidine) at the ends of
the stroke.

Presumably there's enough friction in the wire feed to prevent
excessive overrun when the gear slams to a stop.

--
Ned Simmons


We currently use a rather large urethane bumpers and they get the crap beat out
of them even though the striker is 1" in diameter.




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On Thu, 26 Jun 2008 11:14:33 -0400, "Tom Gardner"
wrote:


We currently use a rather large urethane bumpers and they get the crap beat out
of them even though the striker is 1" in diameter.


Have you seen the Ace Tubus bumpers? I've used a few and they seem to
work better than plain urethane bumpers, though I haven't tried them
in an app where they get really beat on. McMaster carries a limited
selection.

http://www.acecontrols.com/PDF/TUBUS...log%200906.pdf

--
Ned Simmons
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On Jun 26, 11:14 am, "Tom Gardner"
wrote:
"Ned Simmons" wrote in message

...



On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner"
wrote:


I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear
that
would engage the round gear. No, I won't do it with a servo! I'm thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut
in
the middle of the tube to expose teeth to the round gear. This seems simple
and
cheap. In fact, it's so simple it would seem that it should be an
off-the-shelf
item! I just assume it would be easier to do with round rack than square
rack.
Is this available or did I invent a new wheel?


I've seen a mechanism like that; my friend Jim invented it to swing
the head on a die cutting machine in order to nest the cuts and save
material. The guy who invented the rack-type rotary actuator invented
it before him. Jim had cam followers supporting the rack where it
meshed with the gear.


The gear would just spin back and forth and the air cylinder/rack will have an
adjustable stop to get my 80 to 100 degrees rotation. The round gear will
have
a one-way clutch installed because I only want the one direction of shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of
wire.


100ms is pretty fast for an air cylinder which, in this setup, will
probably never stop accelerating 'til it hits the endstop . Make sure
you install bumpers or hydraulic shocks (Ace, Enidine) at the ends of
the stroke.


Presumably there's enough friction in the wire feed to prevent
excessive overrun when the gear slams to a stop.


--
Ned Simmons


We currently use a rather large urethane bumpers and they get the crap beat out
of them even though the striker is 1" in diameter.




Sounds like a need for a valve that will give a burst to get the
mechanism moving, let it coast most of the way (or continue feeding
air somewhat more slowly than full on), then once it hits the stop
give full pressure to hold it against the stop.

Maybe use a couple of valves actuated off the moving parts.


Dave
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On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner"
wrote:

I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that
would engage the round gear. No, I won't do it with a servo! I'm thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in
the middle of the tube to expose teeth to the round gear. This seems simple and
cheap. In fact, it's so simple it would seem that it should be an off-the-shelf
item! I just assume it would be easier to do with round rack than square rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will have an
adjustable stop to get my 80 to 100 degrees rotation. The round gear will have
a one-way clutch installed because I only want the one direction of shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of
wire.

===========
Sounds like another fun project.

Only problem I see is that most off the shelf rack stock is
square, and a round rack will have less tooth contact area which
may not be a concern if the loading is light, unless the rack is
cut on a flat of the shaft.

Can you turn the ends of a square rack round and put some round
extensions on the ends to run in the linear bearings?

Cutting a flat rack on a round shaft should be no problem, but as
the teeth on a rack are straight, it would appear that full teeth
all the way around the shaft could be easily cut on a lathe with
something like an Acme thread bit [14-1/2 PA] possibly with
rounded corners for fatigue resistance. Depth of a 1 mm module /
25 DP tooth is about 0.10 inch. Will 0.30 inch carry the load?

Assuming a 4 inch PD, 3 inches is 85 degrees and 4 inches is 115
degrees.

Another thought is to use a worm gear setup but stroke the worm
back and forth rather than rotating it. IIRC most worms are acme
threads with a DP thread spacing, and this would give you an
single envelopment setup for better contact and longer life.

A 1/2 dia round rack gear indicates a fine DP gear, possible like
a 1MM module [20 degree PA] / 24 DP gear. For examples see
http://americanprecision.thomasnet.c...375fw?&seo=110
http://www.qtcgears.com/RFQ/default....rs/KHK046.html

Let the group know how you make out.

















Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).
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On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner"
wrote:


"Gunner" wrote in message
.. .
On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote:

On Jun 25, 10:37 pm, "Tom Gardner"
wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear
that
would engage the round gear. No, I won't do it with a servo! I'm thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a scallop
cut in
the middle of the tube to expose teeth to the round gear. This seems simple
and
cheap. In fact, it's so simple it would seem that it should be an
off-the-shelf
item! I just assume it would be easier to do with round rack than square
rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will have
an
adjustable stop to get my 80 to 100 degrees rotation. The round gear will
have
a one-way clutch installed because I only want the one direction of shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of
wire.

They make pneumatic rotary actuators to do exactly what you want, turn
a shaft through a partial revolution and back. Kind of like a super-
sized version of the old vacuum windshield wiper motor, uses a vane in
a chamber driven by pressure, not vacuum. Might explain why you don't
see a geared actuator like you describe. Unless you've got a lot of
scrap parts laying around, might be the cheaper way to go!

Stan



I thought I sent one of those to Tom already?

Gunner


I didn't see it, I'd be interested in purchasing one if you still have one!

Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff

Tell you what...Ill email you pictures of the stuff..and if you
want..Ill ship you the entire lot. Might be several thousand pounds
of cylinders, etc etc. All NOS, ablit some has some surface rust in
non critcal places

Free..you pay for the shipping

Gunner
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Default Pneumatic rack and pinion drive

F. George McDuffee fired this volley
in :

On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner"
wrote:

I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms.
I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a
rack gear that would engage the round gear. No, I won't do it with a
servo! I'm thinking a 1/2" round rack gear in a tube with Thomson
linear bearings and a scallop cut in the middle of the tube to expose
teeth to the round gear. This seems simple and cheap. In fact, it's
so simple it would seem that it should be an off-the-shelf item! I
just assume it would be easier to do with round rack than square rack.
Is this available or did I invent a new wheel?



Tom, we have an almost identical device feeding time fuse for cutting.
The assembly consists of a one-way drum clutch inside the feed tire,
moved through a portion of a revolution by a crank rod on the clutch
whose outer end is moved an air cylinder. It moves the fuse from 1/2" to
4.10 inches per stroke, and has nearly zero backlash (for accuracy).

I think that setup is simpler yet than what you described, and does
exactly the same function -- precisely and repeatedly for years without
any maintenance.

LLoyd


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Default Pneumatic rack and pinion drive


"Gunner" wrote in message
...
On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner"
wrote:


"Gunner" wrote in message
. ..
On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote:

On Jun 25, 10:37 pm, "Tom Gardner"
wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms.
I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack
gear
that
would engage the round gear. No, I won't do it with a servo! I'm
thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a
scallop
cut in
the middle of the tube to expose teeth to the round gear. This seems
simple
and
cheap. In fact, it's so simple it would seem that it should be an
off-the-shelf
item! I just assume it would be easier to do with round rack than
square
rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will
have
an
adjustable stop to get my 80 to 100 degrees rotation. The round gear
will
have
a one-way clutch installed because I only want the one direction of
shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to
3-1/4" of
wire.

They make pneumatic rotary actuators to do exactly what you want, turn
a shaft through a partial revolution and back. Kind of like a super-
sized version of the old vacuum windshield wiper motor, uses a vane in
a chamber driven by pressure, not vacuum. Might explain why you don't
see a geared actuator like you describe. Unless you've got a lot of
scrap parts laying around, might be the cheaper way to go!

Stan


I thought I sent one of those to Tom already?

Gunner


I didn't see it, I'd be interested in purchasing one if you still have
one!

Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff

Tell you what...Ill email you pictures of the stuff..and if you
want..Ill ship you the entire lot. Might be several thousand pounds
of cylinders, etc etc. All NOS, ablit some has some surface rust in
non critcal places

Free..you pay for the shipping

Gunner



EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW!


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Default Pneumatic rack and pinion drive

Tom Gardner wrote:
(...)

You have amazing vision, that's exactly what I want to replace, it's not
tolerant of hard/soft/dry/oily wire.



Ah.

In that case I would press the gear on to the end of a combined
clutch/brake. I would run the drive motor continuously and feed
the wire by actuating the clutch, then I would throw out the clutch
and actuate the brake at the end of 'stroke'. Heck, for your app, you
could use opposite poles of a SPDT relay. If the brake isn't on,
the clutch is feeding your wire.

Have a look at the combined clutch/brake units on page 27, 28 of:
http://www.orttech.com/files/pdfs/em206.pdf , for example



--Winston
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"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
F. George McDuffee fired this volley
in :

On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner"
wrote:

I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms.
I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a
rack gear that would engage the round gear. No, I won't do it with a
servo! I'm thinking a 1/2" round rack gear in a tube with Thomson
linear bearings and a scallop cut in the middle of the tube to expose
teeth to the round gear. This seems simple and cheap. In fact, it's
so simple it would seem that it should be an off-the-shelf item! I
just assume it would be easier to do with round rack than square rack.
Is this available or did I invent a new wheel?



Tom, we have an almost identical device feeding time fuse for cutting.
The assembly consists of a one-way drum clutch inside the feed tire,
moved through a portion of a revolution by a crank rod on the clutch
whose outer end is moved an air cylinder. It moves the fuse from 1/2" to
4.10 inches per stroke, and has nearly zero backlash (for accuracy).

I think that setup is simpler yet than what you described, and does
exactly the same function -- precisely and repeatedly for years without
any maintenance.

LLoyd


It's similar to the way we feed staple wire but that uses a mechanical
linkage and a ratchet and pawl rather than a one-way clutch. This is still
in the running because it IS so simple,


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On Thu, 26 Jun 2008 16:13:43 -0400, "Tom Gardner"
wrote:


"Gunner" wrote in message
.. .
On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner"
wrote:


"Gunner" wrote in message
...
On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote:

On Jun 25, 10:37 pm, "Tom Gardner"
wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms.
I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack
gear
that
would engage the round gear. No, I won't do it with a servo! I'm
thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a
scallop
cut in
the middle of the tube to expose teeth to the round gear. This seems
simple
and
cheap. In fact, it's so simple it would seem that it should be an
off-the-shelf
item! I just assume it would be easier to do with round rack than
square
rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will
have
an
adjustable stop to get my 80 to 100 degrees rotation. The round gear
will
have
a one-way clutch installed because I only want the one direction of
shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to
3-1/4" of
wire.

They make pneumatic rotary actuators to do exactly what you want, turn
a shaft through a partial revolution and back. Kind of like a super-
sized version of the old vacuum windshield wiper motor, uses a vane in
a chamber driven by pressure, not vacuum. Might explain why you don't
see a geared actuator like you describe. Unless you've got a lot of
scrap parts laying around, might be the cheaper way to go!

Stan


I thought I sent one of those to Tom already?

Gunner

I didn't see it, I'd be interested in purchasing one if you still have
one!

Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff

Tell you what...Ill email you pictures of the stuff..and if you
want..Ill ship you the entire lot. Might be several thousand pounds
of cylinders, etc etc. All NOS, ablit some has some surface rust in
non critcal places

Free..you pay for the shipping

Gunner



EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW!

Is that a yes, or a no?

Or did you just grab your chest?

G

Say..you dont need v and timing belts do you?

If you dont mind picking out the leaves and the dead bugs, Ive got a
4x4x5 steel container filled with them.' Probably a thousand or so in
there, all NOS, Gates, Martin, Browning, long, short, skinny, fat..As
and Bs, etc


Same deal


Gunner
  #20   Report Post  
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Posts: 1,210
Default Pneumatic rack and pinion drive

On Thu, 26 Jun 2008 16:13:43 -0400, "Tom Gardner"
wrote:


"Gunner" wrote in message
.. .
On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner"
wrote:


"Gunner" wrote in message
...
On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote:

On Jun 25, 10:37 pm, "Tom Gardner"
wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms.
I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack
gear
that
would engage the round gear. No, I won't do it with a servo! I'm
thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a
scallop
cut in
the middle of the tube to expose teeth to the round gear. This seems
simple
and
cheap. In fact, it's so simple it would seem that it should be an
off-the-shelf
item! I just assume it would be easier to do with round rack than
square
rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will
have
an
adjustable stop to get my 80 to 100 degrees rotation. The round gear
will
have
a one-way clutch installed because I only want the one direction of
shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to
3-1/4" of
wire.

They make pneumatic rotary actuators to do exactly what you want, turn
a shaft through a partial revolution and back. Kind of like a super-
sized version of the old vacuum windshield wiper motor, uses a vane in
a chamber driven by pressure, not vacuum. Might explain why you don't
see a geared actuator like you describe. Unless you've got a lot of
scrap parts laying around, might be the cheaper way to go!

Stan


I thought I sent one of those to Tom already?

Gunner

I didn't see it, I'd be interested in purchasing one if you still have
one!

Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff

Tell you what...Ill email you pictures of the stuff..and if you
want..Ill ship you the entire lot. Might be several thousand pounds
of cylinders, etc etc. All NOS, ablit some has some surface rust in
non critcal places

Free..you pay for the shipping

Gunner



EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW!

Oh..if you take the belts...Ill toss in all the right angle drives,
most of the Reeves drives, lovejoy couplers and most of the 3ph
electric motors, leaving only a few of the machine tool specific
motors. And any and all pneumatic valves, solenoids, manifolds
etc..though it might take another pallet. Or 2. Or another one of
those 4x4x5 scrab bins....

Frankly..Id rather you had them, than give them to the scrappers.

Oh..and of course, all the Linear ways, ballscrews etc I already have
boxed for you...that I keep forgetting to ship.

Need any welding rod or wire?



Gunner


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Posted to rec.crafts.metalworking
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Posts: 1,210
Default Pneumatic rack and pinion drive

On Thu, 26 Jun 2008 16:13:43 -0400, "Tom Gardner"
wrote:


"Gunner" wrote in message
.. .
On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner"
wrote:


"Gunner" wrote in message
...
On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote:

On Jun 25, 10:37 pm, "Tom Gardner"
wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms.
I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack
gear
that
would engage the round gear. No, I won't do it with a servo! I'm
thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a
scallop
cut in
the middle of the tube to expose teeth to the round gear. This seems
simple
and
cheap. In fact, it's so simple it would seem that it should be an
off-the-shelf
item! I just assume it would be easier to do with round rack than
square
rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will
have
an
adjustable stop to get my 80 to 100 degrees rotation. The round gear
will
have
a one-way clutch installed because I only want the one direction of
shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to
3-1/4" of
wire.

They make pneumatic rotary actuators to do exactly what you want, turn
a shaft through a partial revolution and back. Kind of like a super-
sized version of the old vacuum windshield wiper motor, uses a vane in
a chamber driven by pressure, not vacuum. Might explain why you don't
see a geared actuator like you describe. Unless you've got a lot of
scrap parts laying around, might be the cheaper way to go!

Stan


I thought I sent one of those to Tom already?

Gunner

I didn't see it, I'd be interested in purchasing one if you still have
one!

Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff

Tell you what...Ill email you pictures of the stuff..and if you
want..Ill ship you the entire lot. Might be several thousand pounds
of cylinders, etc etc. All NOS, ablit some has some surface rust in
non critcal places

Free..you pay for the shipping

Gunner



EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW!

If you are interested, call me. You should have the number

Gunner
  #22   Report Post  
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Posts: 58
Default Pneumatic rack and pinion drive

Gunner wrote:
SNIP



Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff



Green LED's? G


SNIP

Gunner



--
Steve Walker
(remove wallet to reply)
  #23   Report Post  
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Posts: 5,154
Default Pneumatic rack and pinion drive

On Thu, 26 Jun 2008 16:13:43 -0400, with neither quill nor qualm, "Tom
Gardner" quickly quoth:


"Gunner" wrote in message
.. .


Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff

Tell you what...Ill email you pictures of the stuff..and if you
want..Ill ship you the entire lot. Might be several thousand pounds
of cylinders, etc etc. All NOS, ablit some has some surface rust in
non critcal places

Free..you pay for the shipping

Gunner


EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW!


I take it that that is an affirmative, Tawm? guffaw

I'm still working on the free stuff I got from him eons ago.

--
Deep doubts, deep wisdom; small doubts, little wisdom.
--Chinese Proverb
----
  #24   Report Post  
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Posts: 353
Default Pneumatic rack and pinion drive


"Winston" wrote in message
news:EPS8k.55$BR.3@trnddc06...
Tom Gardner wrote:
(...)

You have amazing vision, that's exactly what I want to replace, it's not
tolerant of hard/soft/dry/oily wire.



Ah.

In that case I would press the gear on to the end of a combined
clutch/brake. I would run the drive motor continuously and feed
the wire by actuating the clutch, then I would throw out the clutch
and actuate the brake at the end of 'stroke'. Heck, for your app, you
could use opposite poles of a SPDT relay. If the brake isn't on,
the clutch is feeding your wire.

Have a look at the combined clutch/brake units on page 27, 28 of:
http://www.orttech.com/files/pdfs/em206.pdf , for example



--Winston


Interesting, a quick calc says I need 0.2 hp motor. Motor and clutch won't fit
in the amount of room I have available...easily. But, there are many, many ways
to skin a cat.


  #25   Report Post  
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Posts: 353
Default Pneumatic rack and pinion drive


"Gunner" wrote in message
...
On Thu, 26 Jun 2008 16:13:43 -0400, "Tom Gardner"
wrote:


"Gunner" wrote in message
. ..
On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner"
wrote:


"Gunner" wrote in message
m...
On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote:

On Jun 25, 10:37 pm, "Tom Gardner"
wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms.
I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack
gear
that
would engage the round gear. No, I won't do it with a servo! I'm
thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a
scallop
cut in
the middle of the tube to expose teeth to the round gear. This seems
simple
and
cheap. In fact, it's so simple it would seem that it should be an
off-the-shelf
item! I just assume it would be easier to do with round rack than
square
rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will
have
an
adjustable stop to get my 80 to 100 degrees rotation. The round gear
will
have
a one-way clutch installed because I only want the one direction of
shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to
3-1/4" of
wire.

They make pneumatic rotary actuators to do exactly what you want, turn
a shaft through a partial revolution and back. Kind of like a super-
sized version of the old vacuum windshield wiper motor, uses a vane in
a chamber driven by pressure, not vacuum. Might explain why you don't
see a geared actuator like you describe. Unless you've got a lot of
scrap parts laying around, might be the cheaper way to go!

Stan


I thought I sent one of those to Tom already?

Gunner

I didn't see it, I'd be interested in purchasing one if you still have
one!

Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff

Tell you what...Ill email you pictures of the stuff..and if you
want..Ill ship you the entire lot. Might be several thousand pounds
of cylinders, etc etc. All NOS, ablit some has some surface rust in
non critcal places

Free..you pay for the shipping

Gunner



EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW!

If you are interested, call me. You should have the number

Gunner


I will call! I can't use a lot of that stuff but pneumatics and linear stuff
always comes in handy. I can't believe you aren't listing it all on eBay. For
every ass, there's a seat.




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Posts: 353
Default Pneumatic rack and pinion drive


"Larry Jaques" wrote in message
...
On Thu, 26 Jun 2008 16:13:43 -0400, with neither quill nor qualm, "Tom
Gardner" quickly quoth:


"Gunner" wrote in message
. ..


Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff

Tell you what...Ill email you pictures of the stuff..and if you
want..Ill ship you the entire lot. Might be several thousand pounds
of cylinders, etc etc. All NOS, ablit some has some surface rust in
non critcal places

Free..you pay for the shipping

Gunner


EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW!


I take it that that is an affirmative, Tawm? guffaw

I'm still working on the free stuff I got from him eons ago.

--
Deep doubts, deep wisdom; small doubts, little wisdom.
--Chinese Proverb
----


The down side of free stuff is when you have to replace it, just TRY and find
that model!


  #27   Report Post  
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Posts: 353
Default Pneumatic rack and pinion drive


"Ned Simmons" wrote in message
...
On Thu, 26 Jun 2008 11:14:33 -0400, "Tom Gardner"
wrote:


We currently use a rather large urethane bumpers and they get the crap beat
out
of them even though the striker is 1" in diameter.


Have you seen the Ace Tubus bumpers? I've used a few and they seem to
work better than plain urethane bumpers, though I haven't tried them
in an app where they get really beat on. McMaster carries a limited
selection.

http://www.acecontrols.com/PDF/TUBUS...log%200906.pdf

--
Ned Simmons


Damn Ned, you're a handy guy to know! Why can't I find these kind of things
that would make my life easier?


  #28   Report Post  
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Posts: 353
Default Pneumatic rack and pinion drive


"Karl Townsend" wrote in message
news.com...
For only about 90 degrees of motion you don't need the rack. just use the
crank shaft - connecting rod rod type idea. That is, an air cylinder connected
to a shaft with a lever arm. A short lever arm makes for very fast motion,
less torque.

Karl



This is looking to be the best option. I talked to a couple of "Rotary
Actuator" manufacturers and they both balked when I told them I needed 250 ms
half-cycle time. One second seems to be their comfort zone.


  #29   Report Post  
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Posts: 5,154
Default Pneumatic rack and pinion drive

On Fri, 27 Jun 2008 00:09:12 -0400, with neither quill nor qualm, "Tom
Gardner" quickly quoth:


"Larry Jaques" wrote in message
.. .
On Thu, 26 Jun 2008 16:13:43 -0400, with neither quill nor qualm, "Tom
Gardner" quickly quoth:


"Gunner" wrote in message
...


Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff

Tell you what...Ill email you pictures of the stuff..and if you
want..Ill ship you the entire lot. Might be several thousand pounds
of cylinders, etc etc. All NOS, ablit some has some surface rust in
non critcal places

Free..you pay for the shipping

Gunner

EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW!


I take it that that is an affirmative, Tawm? guffaw

I'm still working on the free stuff I got from him eons ago.

--
Deep doubts, deep wisdom; small doubts, little wisdom.
--Chinese Proverb
----


The down side of free stuff is when you have to replace it, just TRY and find
that model!


Yeah, I'm still trying to locate worm gears for the old Wilton 4x6
saur I got. I should get tires while I'm at it, and by then, I'll be
up to the price of a new HF 4x6. Hmmm...

Neely Bearing wanted $8 and change for the new idler General (Chinese)
62022 bearing for the drill press, with retaining ring. Another local
bearing place, Applied Industrial Technologies wanted $20 for an
identical SKF bearing and no snap ring. I should probably press that
together one of these days. I already had a spare LinkBelt for it.
I dare say that even a Chinese bearing will likely outlast me.

OK, time for the Heller syllabus...

--
Deep doubts, deep wisdom; small doubts, little wisdom.
--Chinese Proverb
----
  #30   Report Post  
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Posts: 657
Default Pneumatic rack and pinion drive

--Hiya; chiming in a little late here, but to see a good
implementation of what you want to build you might head over to
battlebots.com and check out a heavyweight called The Judge. Before it was
dismembered by a spinbot it had a spiked arm on it that could punch holes in
1/4" steel plate. Heh.

--
"Steamboat Ed" Haas : "Hold on! we're passing
Hacking the Trailing Edge! : through the moronosphere!"
www.nmpproducts.com
---Decks a-wash in a sea of words---


  #31   Report Post  
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Posts: 2,600
Default Pneumatic rack and pinion drive

On 2008-06-27, Larry Jaques novalidaddress@di wrote:
On Fri, 27 Jun 2008 00:09:12 -0400, with neither quill nor qualm, "Tom
Gardner" quickly quoth:


[ ... ]

The down side of free stuff is when you have to replace it, just TRY and find
that model!


Yeah, I'm still trying to locate worm gears for the old Wilton 4x6
saur I got. I should get tires while I'm at it, and by then, I'll be
up to the price of a new HF 4x6. Hmmm...


O.K. First question: "saur" -- sort for "dinosaur" to indicate
the age, or just a creative spelling of "saw"?

Second -- does the Wilton 4x6 actually *have* tires? The import
one which I have from MSC has a cast iron wheel with a flange and a
groove to clear the set of the 1/2" blade teeth -- no tire. I thought
that all of the 4x6 saws were like this.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
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Default Pneumatic rack and pinion drive

On 28 Jun 2008 03:27:44 GMT, with neither quill nor qualm, "DoN.
Nichols" quickly quoth:

On 2008-06-27, Larry Jaques novalidaddress@di wrote:
On Fri, 27 Jun 2008 00:09:12 -0400, with neither quill nor qualm, "Tom
Gardner" quickly quoth:


[ ... ]

The down side of free stuff is when you have to replace it, just TRY and find
that model!


Yeah, I'm still trying to locate worm gears for the old Wilton 4x6
saur I got. I should get tires while I'm at it, and by then, I'll be
up to the price of a new HF 4x6. Hmmm...


O.K. First question: "saur" -- sort for "dinosaur" to indicate
the age, or just a creative spelling of "saw"?


Hey, I got it from Gunner. It's a bit of both. g


Second -- does the Wilton 4x6 actually *have* tires? The import
one which I have from MSC has a cast iron wheel with a flange and a
groove to clear the set of the 1/2" blade teeth -- no tire. I thought
that all of the 4x6 saws were like this.


That's the way this is, but someone recently mentioned tires on a
metalworking bandsaw and it got me thinking that maybe I was missing
something. This thing's pretty clapped out and the local ACE hardware
stores now have ShopFox 4x6ers in stock for $149, so...


--
Deep doubts, deep wisdom; small doubts, little wisdom.
--Chinese Proverb
----
  #33   Report Post  
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Posts: 2,600
Default Pneumatic rack and pinion drive

On 2008-06-28, Larry Jaques novalidaddress@di wrote:
On 28 Jun 2008 03:27:44 GMT, with neither quill nor qualm, "DoN.
Nichols" quickly quoth:


[ ... ]

O.K. First question: "saur" -- sort for "dinosaur" to indicate
the age, or just a creative spelling of "saw"?


Hey, I got it from Gunner. It's a bit of both. g


O.K. Good enough.

Second -- does the Wilton 4x6 actually *have* tires? The import
one which I have from MSC has a cast iron wheel with a flange and a
groove to clear the set of the 1/2" blade teeth -- no tire. I thought
that all of the 4x6 saws were like this.


That's the way this is, but someone recently mentioned tires on a
metalworking bandsaw and it got me thinking that maybe I was missing
something. This thing's pretty clapped out and the local ACE hardware
stores now have ShopFox 4x6ers in stock for $149, so...


Hmm ... to put tires on it, you will need to totally re-turn the
wheels -- get rid of the flange, and put in a groove for the root of the
tires. And I don't know whether tires will work well with the design of
the 4x6 -- toss in the sharp twist to the blades, and the short distance
from the guides to the wheels, and I'm not sure what will happen.

The benefit of tires is the ability to use a wide range of blade
widths, and to make them self centering on large wheels which can't be
easily tilted. There are tires on my Emco three-wheeled saw (with
fiberglass-reinforced plastic wheels), but the blade is not twisted like
the 4x6 does, and the guides are less aggressive.

I would suggest keeping the flanged wheels for the 4x6 and just
using it as a cutoff saw (it is pretty useless as a vertical saw -- not
enough throat to allow much work guiding) and get something better with
wheels for freehand sawing to shapes. That's what I do with the Emco
three-wheeled one, which has three belt positions including one
which gives a high enough speed to make sawing aluminum a lot better.
But that is one tiny little belt -- some of these days it is bound to
pop. I just don't have room for a proper floor-standing vertical. The
3-wheeler came from an eBay auction. Emco seems to have discontinued
it.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
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Default Pneumatic rack and pinion drive

On 29 Jun 2008 00:15:39 GMT, with neither quill nor qualm, "DoN.
Nichols" quickly quoth:

On 2008-06-28, Larry Jaques novalidaddress@di wrote:
On 28 Jun 2008 03:27:44 GMT, with neither quill nor qualm, "DoN.
Nichols" quickly quoth:


[ ... ]

O.K. First question: "saur" -- sort for "dinosaur" to indicate
the age, or just a creative spelling of "saw"?


Hey, I got it from Gunner. It's a bit of both. g


O.K. Good enough.

Second -- does the Wilton 4x6 actually *have* tires? The import
one which I have from MSC has a cast iron wheel with a flange and a
groove to clear the set of the 1/2" blade teeth -- no tire. I thought
that all of the 4x6 saws were like this.


That's the way this is, but someone recently mentioned tires on a
metalworking bandsaw and it got me thinking that maybe I was missing
something. This thing's pretty clapped out and the local ACE hardware
stores now have ShopFox 4x6ers in stock for $149, so...


Hmm ... to put tires on it, you will need to totally re-turn the
wheels -- get rid of the flange, and put in a groove for the root of the
tires. And I don't know whether tires will work well with the design of
the 4x6 -- toss in the sharp twist to the blades, and the short distance
from the guides to the wheels, and I'm not sure what will happen.


Waaaay too much work. I thought they might have used very thin tires
on the stepped wheel.


The benefit of tires is the ability to use a wide range of blade
widths, and to make them self centering on large wheels which can't be
easily tilted. There are tires on my Emco three-wheeled saw (with
fiberglass-reinforced plastic wheels), but the blade is not twisted like
the 4x6 does, and the guides are less aggressive.

I would suggest keeping the flanged wheels for the 4x6 and just
using it as a cutoff saw (it is pretty useless as a vertical saw -- not
enough throat to allow much work guiding) and get something better with
wheels for freehand sawing to shapes. That's what I do with the Emco
three-wheeled one, which has three belt positions including one
which gives a high enough speed to make sawing aluminum a lot better.
But that is one tiny little belt -- some of these days it is bound to
pop. I just don't have room for a proper floor-standing vertical. The
3-wheeler came from an eBay auction. Emco seems to have discontinued
it.


I'll likely eBay it to get a good downpayment on a new 4x6. I'm
finding much less time to fiddle when I'm in the shop nowadays.

Besides, I like white tools, though Griz Green is also a fave color.
The lighter the tools in my shop, the brighter the shop.

Now to go clean the shop out so I could possibly _work_ out there
again some day soon...

--
Such is the irresistible nature of truth that all it asks, and all it wants,
is the liberty of appearing. -- Thomas Paine
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