Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #1   Report Post  
frank
 
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Default Cutting pullies on a rotary table on a mill

For a long time now I have been looking for a reasonably prices set of
primary pullies
for my Atlas 10" lathe. No luck for more than a year. It seems really dumb
to pay
$100 for two pullies since the lathe already has a set of usable, but
incorrect,
pullies.

So I have been thinking about making a set on the mill. I have a J-head
Bridgeport
and a 10" rotary table. Even better, I have all the parts to make a
variable speed
power feed for the rotary table. My goal is to make the pullies using as
few
passes as possible; this means getting a cutter to cut the pullies in one or
two passes.

After looking for a while I have not found a cutter for the job.

Since the material is 5/8 6061 T6 aluminum, I have been tempted to put the
mill in the highest speed, fill the mist system with WD40 and use a (wood)
router bit.
Come back in 20 minutes and the first groove is cut.

But if anybody can recommend a usable, if not pefect, cutter for this sort
of task, I am interested in hearing about it.


  #2   Report Post  
Grant Erwin
 
Posts: n/a
Default Cutting pullies on a rotary table on a mill

This sounds crazy enough to maybe work. 20 minutes would be a lot faster
than the 4-step pulley I just made. Mine took me about six hours on a
small lathe. I chucked up a piece of aluminum, then bored and reamed
its central bore. Then, in the same chucking, I mounted a specially
ground tool in a boring bar and stroked the keyway. Then I mounted it
on a mandrel and mounted it in the lathe and faced it fore
and aft then turned it round and then turned the steps and then took the
parting tool and turned all the corners and parted everything to depth
and then swiveled the compound and turned all the sides of the vees.
Then I took it to the mill and drilled and tapped the set screw.
It isn't too hard, just quite a bit of work. It doesn't have much
runout, especially when you compare it with die cast step pulleys.

Grant

frank wrote:

For a long time now I have been looking for a reasonably prices set of
primary pullies
for my Atlas 10" lathe. No luck for more than a year. It seems really dumb
to pay
$100 for two pullies since the lathe already has a set of usable, but
incorrect,
pullies.

So I have been thinking about making a set on the mill. I have a J-head
Bridgeport
and a 10" rotary table. Even better, I have all the parts to make a
variable speed
power feed for the rotary table. My goal is to make the pullies using as
few
passes as possible; this means getting a cutter to cut the pullies in one or
two passes.

After looking for a while I have not found a cutter for the job.

Since the material is 5/8 6061 T6 aluminum, I have been tempted to put the
mill in the highest speed, fill the mist system with WD40 and use a (wood)
router bit.
Come back in 20 minutes and the first groove is cut.

But if anybody can recommend a usable, if not pefect, cutter for this sort
of task, I am interested in hearing about it.



  #3   Report Post  
Ron Thompson
 
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Default Cutting pullies on a rotary table on a mill

Sounds like you did it about like I would, but I suspect the time was due to
your small machine. It would go a lot faster on his atlas.
If I had the lathe I wouldn't even consider doing it on a mill.
http://www.plansandprojects.com/pulleys.htm
--

Ron Thompson
On the Beautiful Mississippi Gulf Coast
USA

http://www.plansandprojects.com

Where did everyone go? Oh, yeah. http://groups.yahoo.com/group/castinghobby/
*******
"Grant Erwin" wrote in message
...
This sounds crazy enough to maybe work. 20 minutes would be a lot faster
than the 4-step pulley I just made. Mine took me about six hours on a
small lathe. I chucked up a piece of aluminum, then bored and reamed
its central bore. Then, in the same chucking, I mounted a specially
ground tool in a boring bar and stroked the keyway. Then I mounted it
on a mandrel and mounted it in the lathe and faced it fore
and aft then turned it round and then turned the steps and then took the
parting tool and turned all the corners and parted everything to depth
and then swiveled the compound and turned all the sides of the vees.
Then I took it to the mill and drilled and tapped the set screw.
It isn't too hard, just quite a bit of work. It doesn't have much
runout, especially when you compare it with die cast step pulleys.

Grant

frank wrote:

For a long time now I have been looking for a reasonably prices set of
primary pullies
for my Atlas 10" lathe. No luck for more than a year. It seems really

dumb
to pay
$100 for two pullies since the lathe already has a set of usable, but
incorrect,
pullies.

So I have been thinking about making a set on the mill. I have a J-head
Bridgeport
and a 10" rotary table. Even better, I have all the parts to make a
variable speed
power feed for the rotary table. My goal is to make the pullies using

as
few
passes as possible; this means getting a cutter to cut the pullies in

one or
two passes.

After looking for a while I have not found a cutter for the job.

Since the material is 5/8 6061 T6 aluminum, I have been tempted to put

the
mill in the highest speed, fill the mist system with WD40 and use a

(wood)
router bit.
Come back in 20 minutes and the first groove is cut.

But if anybody can recommend a usable, if not pefect, cutter for this

sort
of task, I am interested in hearing about it.






  #4   Report Post  
Harold & Susan Vordos
 
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Default Cutting pullies on a rotary table on a mill


"Grant Erwin" wrote in message
...

It doesn't have much
runout, especially when you compare it with die cast step pulleys.

Grant

If you'd learn to rough your parts before finishing, runout would be a thing
of the past (assuming you used proper machine procedures, that is!). It
is not good practice to machines parts to size on one side, then turn a
second side, especially when removing a lot of material. Good policy
dictates that you would leave about .05" on the surfaces for finish
machining, which would remove any runout you would have from stress
relieving. It also helps prevent damage to your work because finishing
operations tend to be much lighter, thus demanding much lighter chucking
pressures..

Harold


  #5   Report Post  
frank
 
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Default Cutting pullies on a rotary table on a mill


The key problem is the large pulley cannot be cut on the lathe. It will not
fit.

The only other power tool I have to do the work is a mill/rotary table, and
since
I have to set that up to do the work on one pulley, it seems like a good
idea to
just cut all 4.

But in practice I would probably cut one pulley on the lathe while the
mill/rotary table
chewed away at one pulley.

My Atlas has a 1/2 hp motor and the Bridgeport has a 1 hp motor. Blowing
through
6061 T6 with not-that-high precision seems to be a function of motor hp and
little
else. The mill wil be quicker.

"Ron Thompson" wrote in message
. ..
Sounds like you did it about like I would, but I suspect the time was due

to
your small machine. It would go a lot faster on his atlas.
If I had the lathe I wouldn't even consider doing it on a mill.
http://www.plansandprojects.com/pulleys.htm






  #6   Report Post  
Nick Mueller
 
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Default Cutting pullies on a rotary table on a mill

frank wrote:

But if anybody can recommend a usable, if not pefect, cutter for this sort
of task, I am interested in hearing about it.


How about making your own? Precut it with something that fits more or
less and do the rest with your home built cutter.


Nick
--
Never use force, just go and get a bigger hammer.
  #7   Report Post  
DoN. Nichols
 
Posts: n/a
Default Cutting pullies on a rotary table on a mill

In article , frank wrote:

The key problem is the large pulley cannot be cut on the lathe. It will not
fit.

The only other power tool I have to do the work is a mill/rotary table, and
since
I have to set that up to do the work on one pulley, it seems like a good
idea to
just cut all 4.


[ ... ]

My Atlas has a 1/2 hp motor and the Bridgeport has a 1 hp motor. Blowing
through
6061 T6 with not-that-high precision seems to be a function of motor hp and
little
else. The mill wil be quicker.


Do you have a stub arbor for conventional milling cutters (those
for horizontal mills)? If so, what you might be able to do is first cut
a groove to the depth of the pulley's needed 'V' with a standard one,
then take a somewhat wider one, and have it ground to match the profile
of the 'V'. (This will need someone skilled at using a Tool and Cutter
grinder, but will result in pulleys with all 'V' the right shape. (It
will also probably fill the shop floor with chips. :-)

I would be more tempted to use a horizontal miller with the
rotary table -- but that is in part because I *have* such a miller.

Probably the most critical feature would be the design of the
clamping part on the stub arbor -- you run the risk of running into the
next sized step with the hub -- unless you started out with a rather
large milling cutter before modifying it to 'V-groove shape. Be sure to
lock up all axis motions which don't need to move, as this is going to
be asking for chatter with a vertical spindle mill.

Good Luck,
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 ---
  #8   Report Post  
JMartin957
 
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Default Cutting pullies on a rotary table on a mill


The key problem is the large pulley cannot be cut on the lathe. It will not
fit.


Do you really need a pulley larger than a 10" for that lathe? Seems awfully
large to me.

John Martin
  #9   Report Post  
frank
 
Posts: n/a
Default Cutting pullies on a rotary table on a mill

A perfectly valid question.

The fact is the standard pullies are a specific size. Regardless of what
size they
are, they are a specific size. Does one actually NEED the standard pullies?
No; my lathe has been run without them for at least a decade.

The first reason (pulley) size matters is the cutting tables that came with
the lathe.
They are all wrong if the pullies are wrong. Second, I bought a nice
visual aid -- essentially a 3-dimensional graph, where the common
cutting issues on this lathe are addressd. It is useless if the pullies are
wrong. Third, just for the sake of completeness, it would be nice to
have the standard pullies. Finally, I do have all the tools required
to make the pullies, so this seems like a good project.

A few years back I cut some pullies out of solid aluminum for use in
some very nice snatch blocks. This was done on my mill, using a
ball endmill and a rotary table in vertical mode. It was a near tangental
cut, and I cranked the table on the mill to get the right depth.

When my neighbor moved out he gave me (literally) a pile of very heavy
cutters for horizontal mills. They have removable teeth. Right now I am
thinking about an R8 stub arbor using one of these removable-tooth
cutters. I can grind three teeth -- left, right and bottom -- to make the
cut.


"JMartin957" wrote in message
...

The key problem is the large pulley cannot be cut on the lathe. It will

not
fit.


Do you really need a pulley larger than a 10" for that lathe? Seems

awfully
large to me.

John Martin



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