Plastic roll pin
 

I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it gets
hot then it gets bendy. The company's lab came up with a fix that
involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4" long
with a .312" slit along the side and pressing it into the middle of the
12" tube to act as a stiffener.

What's the cheapest way to make these? Is there a better solution?
They need 10k+ of these. They will supply the Derlin material.

Plastic roll pin
 

On 7/12/2014 1:20 AM, Tom Gardner wrote:
I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it gets
hot then it gets bendy. The company's lab came up with a fix that
involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4" long
with a .312" slit along the side and pressing it into the middle of the
12" tube to act as a stiffener.

What's the cheapest way to make these? Is there a better solution? They
need 10k+ of these. They will supply the Derlin material.

I forgot to mention that one end gets a 30 deg chamfer to aid insertion.

Plastic roll pin
 

Tom Gardner wrote:
I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it gets
hot then it gets bendy. The company's lab came up with a fix that
involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4" long
with a .312" slit along the side and pressing it into the middle of the
12" tube to act as a stiffener.

What's the cheapest way to make these? Is there a better solution?
They need 10k+ of these. They will supply the Derlin material.


Cheapest = outsource to China/Viet Nam...

Slit the tube first, for that a cheap small table saw with guides on
both sides and top of the blade and a narrow fin inline with the blade
on the outfeed to keep the cut nice and straight.

Next, modify a cheap lathe. Make an internally tapered collet that gets
placed in the jaws or welded in place on the spindle. Tubing gets
compressed as it enters the taper until the slot is closed where it
exits the collet. Have a stop placed 4" away with a modified live center
with a 2" or so pin that is a tight fit in the compressed tube and a
sleeve on the outside the same length. Have the tail stock on a pivot so
it can on a pivot away from the operator and a position stop when it
comes back.
Make a chamfer tool and a parting tool. Mount both on pivots with stops.

In use the tubes get slit, then pushed into the "lathe". Quick chamfer
on the end. Push through onto the stop set to give you a 4" section.
Chamfer first then part off. Part will open but be secured from motion
by the internal pin and external sleeve. Operator pivots part and tail
stock away while pushing part out of sleeve and off pin into "finished"
bin behind the machine. Pull the tail stock back into position, feed in
more tube and repeat process.

Basically a home brew chucker screw machine.

--
Steve W.

Plastic roll pin
 

On 7/12/2014 2:33 AM, Steve W. wrote:
Tom Gardner wrote:
I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it
gets hot then it gets bendy. The company's lab came up with a fix
that involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4"
long with a .312" slit along the side and pressing it into the middle
of the 12" tube to act as a stiffener.

What's the cheapest way to make these? Is there a better solution?
They need 10k+ of these. They will supply the Derlin material.


Cheapest = outsource to China/Viet Nam...

Slit the tube first, for that a cheap small table saw with guides on
both sides and top of the blade and a narrow fin inline with the blade
on the outfeed to keep the cut nice and straight.

Next, modify a cheap lathe. Make an internally tapered collet that gets
placed in the jaws or welded in place on the spindle. Tubing gets
compressed as it enters the taper until the slot is closed where it
exits the collet. Have a stop placed 4" away with a modified live center
with a 2" or so pin that is a tight fit in the compressed tube and a
sleeve on the outside the same length. Have the tail stock on a pivot so
it can on a pivot away from the operator and a position stop when it
comes back.
Make a chamfer tool and a parting tool. Mount both on pivots with stops.

In use the tubes get slit, then pushed into the "lathe". Quick chamfer
on the end. Push through onto the stop set to give you a 4" section.
Chamfer first then part off. Part will open but be secured from motion
by the internal pin and external sleeve. Operator pivots part and tail
stock away while pushing part out of sleeve and off pin into "finished"
bin behind the machine. Pull the tail stock back into position, feed in
more tube and repeat process.

Basically a home brew chucker screw machine.



I see. My first thought was to part and chamfer in one cut then to slit
on a router table with an out-feed fin as guide to keep it
straight...but I like your set-up. The other thought was to farm out
the parting and boring and chamfering and do the slitting in-house.

Plastic roll pin
 

On Sat, 12 Jul 2014 02:56:21 -0400, Tom Gardner Mars@Tacks wrote:

On 7/12/2014 2:33 AM, Steve W. wrote:
Tom Gardner wrote:
I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it
gets hot then it gets bendy. The company's lab came up with a fix
that involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4"
long with a .312" slit along the side and pressing it into the middle
of the 12" tube to act as a stiffener.

What's the cheapest way to make these? Is there a better solution?
They need 10k+ of these. They will supply the Derlin material.


Cheapest = outsource to China/Viet Nam...

Slit the tube first, for that a cheap small table saw with guides on
both sides and top of the blade and a narrow fin inline with the blade
on the outfeed to keep the cut nice and straight.

Next, modify a cheap lathe. Make an internally tapered collet that gets
placed in the jaws or welded in place on the spindle. Tubing gets
compressed as it enters the taper until the slot is closed where it
exits the collet. Have a stop placed 4" away with a modified live center
with a 2" or so pin that is a tight fit in the compressed tube and a
sleeve on the outside the same length. Have the tail stock on a pivot so
it can on a pivot away from the operator and a position stop when it
comes back.
Make a chamfer tool and a parting tool. Mount both on pivots with stops.

In use the tubes get slit, then pushed into the "lathe". Quick chamfer
on the end. Push through onto the stop set to give you a 4" section.
Chamfer first then part off. Part will open but be secured from motion
by the internal pin and external sleeve. Operator pivots part and tail
stock away while pushing part out of sleeve and off pin into "finished"
bin behind the machine. Pull the tail stock back into position, feed in
more tube and repeat process.

Basically a home brew chucker screw machine.



I see. My first thought was to part and chamfer in one cut then to slit
on a router table with an out-feed fin as guide to keep it
straight...but I like your set-up. The other thought was to farm out
the parting and boring and chamfering and do the slitting in-house.

Any CNC lathe with a bar feed could knock out the part bore and
chamfer with maybe a 30 second cycle time. No need to build a special
machine.

My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

Karl

Plastic roll pin
 

On 7/12/2014 5:29 AM, Karl Townsend wrote:
...
My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

The trade off is slitting 15 4" pieces vs 1 5' piece.

BTW - I found a source for 1" x 3/4" Delrin that prices it at $37 per 5'
piece. $2.50 material cost for each 4" piece! 'Course when you're
buying 2500', you'll get a better price, I hope.

Bob

Plastic roll pin
 

On 7/12/2014 1:20 AM, Tom Gardner wrote:
... Is there a better solution? ...

A wooden plug?

Plastic roll pin
 

On Sat, 12 Jul 2014 01:20:29 -0400, Tom Gardner Mars@Tacks wrote:

I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it gets
hot then it gets bendy. The company's lab came up with a fix that
involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4" long
with a .312" slit along the side and pressing it into the middle of the
12" tube to act as a stiffener.

S/B Delrin, eh? Rather than this kludge, why didn't the labs redesign
the brush properly? That seems foolish.


What's the cheapest way to make these? Is there a better solution?
They need 10k+ of these. They will supply the Derlin material.

On a CNC lathe/machining center.

--
Liberalism is a pathology.

Plastic roll pin
 

In article , Tom Gardner
Mars@Tacks wrote:

On 7/12/2014 1:20 AM, Tom Gardner wrote:
I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it gets
hot then it gets bendy. The company's lab came up with a fix that
involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4" long
with a .312" slit along the side and pressing it into the middle of the
12" tube to act as a stiffener.

What's the cheapest way to make these? Is there a better solution? They
need 10k+ of these. They will supply the Derlin material.

I forgot to mention that one end gets a 30 deg chamfer to aid insertion.

This volume (10k units) is on the edge economically, but Delrin can be
injection molded.

Joe Gwinn

Plastic roll pin
 

Tom Gardner wrote:

I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it gets
hot then it gets bendy. The company's lab came up with a fix that
involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4" long
with a .312" slit along the side and pressing it into the middle of the
12" tube to act as a stiffener.

What's the cheapest way to make these? Is there a better solution?
They need 10k+ of these. They will supply the Derlin material.

Cut to length with a standard automatic bandsaw if you have one,
otherwise use a table saw with a jig to allow fast cutoff feeding from
the presumably long stock.

Make a custom chamfering head that has a bore to match the OD of the
tube and a standard insert to cut the chamfer (look for HSS inserts).
Incorporate the depth stop in the head so you just push the tube in
until it bottoms out on the flat part of the front. Continue a bore and
a side port for chip evacuation and surround that with a connection to a
shop vac / dust collector. Mount the whole head on a basic motor so you
don't tie up any normal machines.

Do the slotting on a cheap table saw, with a holding fixture for the
tube. Something with a chamber in the bottom you put the tube into where
the tube sits slightly past the bottom of the fixture so you can apply
down pressure to keep it from rotating. Position the operator and parts
bins so they can pickup a tube, place it in the bottom of the fixture as
they slide it over the saw table, run it over the blade between a pair
of fences perhaps 2" apart, and as they run it off the end of the table
the completed part falls into a bin. Minimal labor and pretty fast.

For insertion do a simple pneumatic press setup where you drop a brush
and a tube in the press fixture and hit the button or foot pedal to
press in to the preset depth. This could be automated easily with some
gates to allow you to just load some feed bins and let the cycle work
automatically.

If the quantity was higher or this was to be a regular job, a lot more
automation could be applied pretty easily.

Plastic roll pin
 

On 7/12/2014 9:02 AM, Bob Engelhardt wrote:
On 7/12/2014 5:29 AM, Karl Townsend wrote:
...
My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

The trade off is slitting 15 4" pieces vs 1 5' piece.

BTW - I found a source for 1" x 3/4" Delrin that prices it at $37 per 5'
piece. $2.50 material cost for each 4" piece! 'Course when you're
buying 2500', you'll get a better price, I hope.

Bob


Their lab tried that size and it's too small.

Plastic roll pin
 

On 7/12/2014 9:07 AM, Bob Engelhardt wrote:
On 7/12/2014 1:20 AM, Tom Gardner wrote:
... Is there a better solution? ...

A wooden plug?



Wet environment. I suggested it.

Plastic roll pin
 

On 7/12/2014 9:26 AM, Larry Jaques wrote:
On Sat, 12 Jul 2014 01:20:29 -0400, Tom Gardner Mars@Tacks wrote:

I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it gets
hot then it gets bendy. The company's lab came up with a fix that
involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4" long
with a .312" slit along the side and pressing it into the middle of the
12" tube to act as a stiffener.

S/B Delrin, eh? Rather than this kludge, why didn't the labs redesign
the brush properly? That seems foolish.


What's the cheapest way to make these? Is there a better solution?
They need 10k+ of these. They will supply the Derlin material.

On a CNC lathe/machining center.

--
Liberalism is a pathology.


They did. They don't want to scrap the parts already made. Unless the
fix is too expensive.

Plastic roll pin
 

On 7/12/2014 5:29 AM, Karl Townsend wrote:
On Sat, 12 Jul 2014 02:56:21 -0400, Tom Gardner Mars@Tacks wrote:

On 7/12/2014 2:33 AM, Steve W. wrote:
Tom Gardner wrote:
I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it
gets hot then it gets bendy. The company's lab came up with a fix
that involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4"
long with a .312" slit along the side and pressing it into the middle
of the 12" tube to act as a stiffener.

What's the cheapest way to make these? Is there a better solution?
They need 10k+ of these. They will supply the Derlin material.


Cheapest = outsource to China/Viet Nam...

Slit the tube first, for that a cheap small table saw with guides on
both sides and top of the blade and a narrow fin inline with the blade
on the outfeed to keep the cut nice and straight.

Next, modify a cheap lathe. Make an internally tapered collet that gets
placed in the jaws or welded in place on the spindle. Tubing gets
compressed as it enters the taper until the slot is closed where it
exits the collet. Have a stop placed 4" away with a modified live center
with a 2" or so pin that is a tight fit in the compressed tube and a
sleeve on the outside the same length. Have the tail stock on a pivot so
it can on a pivot away from the operator and a position stop when it
comes back.
Make a chamfer tool and a parting tool. Mount both on pivots with stops.

In use the tubes get slit, then pushed into the "lathe". Quick chamfer
on the end. Push through onto the stop set to give you a 4" section.
Chamfer first then part off. Part will open but be secured from motion
by the internal pin and external sleeve. Operator pivots part and tail
stock away while pushing part out of sleeve and off pin into "finished"
bin behind the machine. Pull the tail stock back into position, feed in
more tube and repeat process.

Basically a home brew chucker screw machine.



I see. My first thought was to part and chamfer in one cut then to slit
on a router table with an out-feed fin as guide to keep it
straight...but I like your set-up. The other thought was to farm out
the parting and boring and chamfering and do the slitting in-house.

Any CNC lathe with a bar feed could knock out the part bore and
chamfer with maybe a 30 second cycle time. No need to build a special
machine.

My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

Karl



I did talk to a guy that make CNC parts for me and he doesn't want to
deal with the plastic swarf.

Plastic roll pin
 

Any CNC lathe with a bar feed could knock out the part bore and
chamfer with maybe a 30 second cycle time. No need to build a special
machine.

My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

Karl



I did talk to a guy that make CNC parts for me and he doesn't want to
deal with the plastic swarf.


I've not done 10K parts but I found a shop vac to work real well for
plastic swarf. Maybe you don't want to go there, but this might be a
good time to buy your first CNC lathe.

Karl

Plastic roll pin
 

On 7/12/2014 12:43 PM, Karl Townsend wrote:

Any CNC lathe with a bar feed could knock out the part bore and
chamfer with maybe a 30 second cycle time. No need to build a special
machine.

My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

Karl



I did talk to a guy that make CNC parts for me and he doesn't want to
deal with the plastic swarf.


I've not done 10K parts but I found a shop vac to work real well for
plastic swarf. Maybe you don't want to go there, but this might be a
good time to buy your first CNC lathe.

Karl


No, I'm at the stage in my life that it's time to divest rather than buy
stuff...except fishing rods and reels and pistols.

Plastic roll pin
 

"Tom Gardner" wrote in message
...

On 7/12/2014 9:02 AM, Bob Engelhardt wrote:
On 7/12/2014 5:29 AM, Karl Townsend wrote:
...
My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

The trade off is slitting 15 4" pieces vs 1 5' piece.

BTW - I found a source for 1" x 3/4" Delrin that prices it at $37 per 5'
piece. $2.50 material cost for each 4" piece! 'Course when you're
buying 2500', you'll get a better price, I hope.

Bob


Their lab tried that size and it's too small.
[/quote]

So when you say they will supply the Delrin, does that mean they supply
tubing with the correct id and od, or what? If the outside is going to need
turning to size, use the 1" tubing, do the cut/deburr/slot ops then slide
each piece onto a SS tube mandrel (have to experiment a bit on the size) and
toss piles of them into an oven at 425F or so for 30-45 minutes. The Delrin
will anneal and relax and take up the new ID of the mandrel +/- a bit, so
you get your correct od without turning the full length. Two sets of
mandrels so while one batch is baking the other is cooled, finished tubes
removed, new ones loaded on the mandrels and the mandrels loaded into a
crate maybe standing them on pegs or whatever, so the entire oven can be
unloaded and reloaded quickly. Anyway, just a suggestion.

-----
Regards,
Carl Ijames

Plastic roll pin
 

On 7/12/2014 1:06 PM, Carl Ijames wrote:
"Tom Gardner" wrote in message
...

On 7/12/2014 9:02 AM, Bob Engelhardt wrote:
On 7/12/2014 5:29 AM, Karl Townsend wrote:
...
My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

The trade off is slitting 15 4" pieces vs 1 5' piece.

BTW - I found a source for 1" x 3/4" Delrin that prices it at $37 per 5'
piece. $2.50 material cost for each 4" piece! 'Course when you're
buying 2500', you'll get a better price, I hope.

Bob


Their lab tried that size and it's too small.
[/quote]

So when you say they will supply the Delrin, does that mean they supply
tubing with the correct id and od, or what? If the outside is going to need
turning to size, use the 1" tubing, do the cut/deburr/slot ops then slide
each piece onto a SS tube mandrel (have to experiment a bit on the size) and
toss piles of them into an oven at 425F or so for 30-45 minutes. The Delrin
will anneal and relax and take up the new ID of the mandrel +/- a bit, so
you get your correct od without turning the full length. Two sets of
mandrels so while one batch is baking the other is cooled, finished tubes
removed, new ones loaded on the mandrels and the mandrels loaded into a
crate maybe standing them on pegs or whatever, so the entire oven can be
unloaded and reloaded quickly. Anyway, just a suggestion.

-----
Regards,
Carl Ijames




They will supply tubing 1.040" UD x .500" ID and want it bored to
11/16". I wonder if their original size of 1" OD x .75" id could be
stretched open to provide more holding power? That would eliminate yhe
boring op.

Plastic roll pin
 

On Saturday, July 12, 2014 6:07:45 AM UTC-7, Bob Engelhardt wrote:
On 7/12/2014 1:20 AM, Tom Gardner wrote:

... Is there a better solution? ...

A wooden plug?

Yeah, with some foaming/expanding glue. Delrin is EXPENSIVE!

Plastic roll pin
 

On Saturday, July 12, 2014 8:53:34 AM UTC-7, Pete C. wrote:
Tom Gardner wrote:

I want to bid on a part for a floor washing brush.
...involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4" long

Cut to length with a standard automatic bandsaw if you have one,
otherwise use a table saw with a jig

If you're getting 10,000 or more, ask the plastic supplier to
supply it in the lengths you want. For them, it's a
simple adjustment.

Plastic roll pin
 

On 7/12/2014 11:53 AM, Tom Gardner wrote:
On 7/12/2014 9:02 AM, Bob Engelhardt wrote:
....
BTW - I found a source for 1" x 3/4" Delrin that prices it at $37 per 5'
piece. $2.50 material cost for each 4" piece! 'Course when you're
buying 2500', you'll get a better price, I hope.

Bob


Their lab tried that size and it's too small.

Yeah, I was just commenting on the price, not suggesting a source.

Plastic roll pin
 

"Tom Gardner" Mars@Tacks wrote in message
...

They will supply tubing 1.040" UD x .500" ID and want it bored to
11/16". I wonder if their original size of 1" OD x .75" id could be
stretched open to provide more holding power? That would eliminate
yhe boring op.

FWIW, 3/4" pipe and PVC electrical conduit is 1.050" OD by 0.824" ID.
-jsw

Plastic roll pin
 

"Tom Gardner" wrote in message
...

On 7/12/2014 1:06 PM, Carl Ijames wrote:
"Tom Gardner" wrote in message
...

On 7/12/2014 9:02 AM, Bob Engelhardt wrote:
On 7/12/2014 5:29 AM, Karl Townsend wrote:
...
My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

The trade off is slitting 15 4" pieces vs 1 5' piece.

BTW - I found a source for 1" x 3/4" Delrin that prices it at $37 per 5'
piece. $2.50 material cost for each 4" piece! 'Course when you're
buying 2500', you'll get a better price, I hope.

Bob


Their lab tried that size and it's too small.
[/quote]

So when you say they will supply the Delrin, does that mean they supply
tubing with the correct id and od, or what? If the outside is going to
need
turning to size, use the 1" tubing, do the cut/deburr/slot ops then slide
each piece onto a SS tube mandrel (have to experiment a bit on the size)
and
toss piles of them into an oven at 425F or so for 30-45 minutes. The
Delrin
will anneal and relax and take up the new ID of the mandrel +/- a bit, so
you get your correct od without turning the full length. Two sets of
mandrels so while one batch is baking the other is cooled, finished tubes
removed, new ones loaded on the mandrels and the mandrels loaded into a
crate maybe standing them on pegs or whatever, so the entire oven can be
unloaded and reloaded quickly. Anyway, just a suggestion.

-----
Regards,
Carl Ijames


They will supply tubing 1.040" UD x .500" ID and want it bored to
11/16". I wonder if their original size of 1" OD x .75" id could be
stretched open to provide more holding power? That would eliminate yhe
boring op.
[/quote]

I figured I better check if you are going to try this, and my memory was a
little off. Here's a table I found online for lots of different plastics,
handy as a guide http://www.boedeker.com/anneal.htm. I was using 1/32"
thick by 1" Delrin strip that was straight, cutting 9" lengths, coiling them
inside a 1-3/4" od stainless steel tube, putting four side by side and four
layers. Any more layers and the id was too small. Put that into a toaster
over that is room temp-ish, set to 325F and turn it on. It was a big oven
that could do a 12" frozen pizza so it had a decent amount of heater power.
I used the convection toast setting so the fan, upper heaters, and lower
heaters were all on. Reached temp in about 20-30 minutes and the timer
turned it off after 45 minutes so 15 minutes at full temp for the soak. Let
cool to under 175F, maybe 45 minutes, so I could grab it barehanded, pop out
the coils and reload. That gave me coiled rings I snapped around 3" iron
pipe as trim rings that would grab tightly enough to stay put but if the
annealed diameter got too small they wouldn't lay flat and look good. I
wasn't going for a perfect anneal, I just needed them to hold the coiled
shape. Anyway, that table recommends a much slower heat and cool, soaking
at 300F, but that is a general recommendation for machined pieces up to 1/4"
thick. Your pieces will be thinner and I don't think need the greatest
precision so you can rush it a good bit. Yes, I'm sure the 1" od would work
fine - you can even make the slit 1/4" since it will grow about 1/8" when
you anneal to the larger dia.

-----
Regards,
Carl Ijames
"Tom Gardner" wrote in message
...

On 7/12/2014 1:06 PM, Carl Ijames wrote:
"Tom Gardner" wrote in message
...

On 7/12/2014 9:02 AM, Bob Engelhardt wrote:
On 7/12/2014 5:29 AM, Karl Townsend wrote:
...
My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

The trade off is slitting 15 4" pieces vs 1 5' piece.

BTW - I found a source for 1" x 3/4" Delrin that prices it at $37 per 5'
piece. $2.50 material cost for each 4" piece! 'Course when you're
buying 2500', you'll get a better price, I hope.

Bob


Their lab tried that size and it's too small.
[/quote]

So when you say they will supply the Delrin, does that mean they supply
tubing with the correct id and od, or what? If the outside is going to
need
turning to size, use the 1" tubing, do the cut/deburr/slot ops then slide
each piece onto a SS tube mandrel (have to experiment a bit on the size)
and
toss piles of them into an oven at 425F or so for 30-45 minutes. The
Delrin
will anneal and relax and take up the new ID of the mandrel +/- a bit, so
you get your correct od without turning the full length. Two sets of
mandrels so while one batch is baking the other is cooled, finished tubes
removed, new ones loaded on the mandrels and the mandrels loaded into a
crate maybe standing them on pegs or whatever, so the entire oven can be
unloaded and reloaded quickly. Anyway, just a suggestion.

-----
Regards,
Carl Ijames




They will supply tubing 1.040" UD x .500" ID and want it bored to
11/16". I wonder if their original size of 1" OD x .75" id could be
stretched open to provide more holding power? That would eliminate yhe
boring op.

Plastic roll pin
 

Tom Gardner wrote:

No, I'm at the stage in my life that it's time to divest rather than buy
stuff...except fishing rods and reels and pistols.


You kinky lesbians, and your sex toys...


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

Plastic roll pin
 

On Sat, 12 Jul 2014 15:24:10 -0400, Tom Gardner Mars@Tacks wrote:

On 7/12/2014 1:06 PM, Carl Ijames wrote:
"Tom Gardner" wrote in message
...

On 7/12/2014 9:02 AM, Bob Engelhardt wrote:
On 7/12/2014 5:29 AM, Karl Townsend wrote:
...
My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

The trade off is slitting 15 4" pieces vs 1 5' piece.

BTW - I found a source for 1" x 3/4" Delrin that prices it at $37 per 5'
piece. $2.50 material cost for each 4" piece! 'Course when you're
buying 2500', you'll get a better price, I hope.

Bob


Their lab tried that size and it's too small.
[/quote]

So when you say they will supply the Delrin, does that mean they supply
tubing with the correct id and od, or what? If the outside is going to need
turning to size, use the 1" tubing, do the cut/deburr/slot ops then slide
each piece onto a SS tube mandrel (have to experiment a bit on the size) and
toss piles of them into an oven at 425F or so for 30-45 minutes. The Delrin
will anneal and relax and take up the new ID of the mandrel +/- a bit, so
you get your correct od without turning the full length. Two sets of
mandrels so while one batch is baking the other is cooled, finished tubes
removed, new ones loaded on the mandrels and the mandrels loaded into a
crate maybe standing them on pegs or whatever, so the entire oven can be
unloaded and reloaded quickly. Anyway, just a suggestion.

-----
Regards,
Carl Ijames




They will supply tubing 1.040" UD x .500" ID and want it bored to
11/16". I wonder if their original size of 1" OD x .75" id could be
stretched open to provide more holding power? That would eliminate yhe
boring op.

The more you tell us, the more I see why they're still looking for a
supplier. I'd run away if I were you, Tawm.

P.S: What's their lab guy's name, DeweyBob? (as in "Hey, hold my beer
and watch this!")

--
Liberalism is a pathology.

Plastic roll pin
 

On Sat, 12 Jul 2014 11:58:31 -0400, Tom Gardner Mars@Tacks wrote:

On 7/12/2014 5:29 AM, Karl Townsend wrote:
On Sat, 12 Jul 2014 02:56:21 -0400, Tom Gardner Mars@Tacks wrote:

On 7/12/2014 2:33 AM, Steve W. wrote:
Tom Gardner wrote:
I want to bid on a part for a floor washing brush. The company made a
bunch of PVC tubes 1" ID X 1.375 OD x 12" long. It's covered with a
material that looks like carpet...'kinda. It works great until it
gets hot then it gets bendy. The company's lab came up with a fix
that involves a taking a Derlin tube that's 1.040" OD x .75" ID x 4"
long with a .312" slit along the side and pressing it into the middle
of the 12" tube to act as a stiffener.

What's the cheapest way to make these? Is there a better solution?
They need 10k+ of these. They will supply the Derlin material.


Cheapest = outsource to China/Viet Nam...

Slit the tube first, for that a cheap small table saw with guides on
both sides and top of the blade and a narrow fin inline with the blade
on the outfeed to keep the cut nice and straight.

Next, modify a cheap lathe. Make an internally tapered collet that gets
placed in the jaws or welded in place on the spindle. Tubing gets
compressed as it enters the taper until the slot is closed where it
exits the collet. Have a stop placed 4" away with a modified live center
with a 2" or so pin that is a tight fit in the compressed tube and a
sleeve on the outside the same length. Have the tail stock on a pivot so
it can on a pivot away from the operator and a position stop when it
comes back.
Make a chamfer tool and a parting tool. Mount both on pivots with stops.

In use the tubes get slit, then pushed into the "lathe". Quick chamfer
on the end. Push through onto the stop set to give you a 4" section.
Chamfer first then part off. Part will open but be secured from motion
by the internal pin and external sleeve. Operator pivots part and tail
stock away while pushing part out of sleeve and off pin into "finished"
bin behind the machine. Pull the tail stock back into position, feed in
more tube and repeat process.

Basically a home brew chucker screw machine.



I see. My first thought was to part and chamfer in one cut then to slit
on a router table with an out-feed fin as guide to keep it
straight...but I like your set-up. The other thought was to farm out
the parting and boring and chamfering and do the slitting in-house.

Any CNC lathe with a bar feed could knock out the part bore and
chamfer with maybe a 30 second cycle time. No need to build a special
machine.

My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

Karl



I did talk to a guy that make CNC parts for me and he doesn't want to
deal with the plastic swarf.

I can see his point. It's extremely statically charged and sticks to
everything. I've slit PVC pipe and don't think I want to try THAT
again.

--
Liberalism is a pathology.

Plastic roll pin
 

On 7/12/2014 8:02 AM, Bob Engelhardt wrote:
On 7/12/2014 5:29 AM, Karl Townsend wrote:
...
My *guess* is pre sltting would not be any easier and would slow down
the CNC lathe work.

The trade off is slitting 15 4" pieces vs 1 5' piece.

BTW - I found a source for 1" x 3/4" Delrin that prices it at $37 per 5'
piece. $2.50 material cost for each 4" piece! 'Course when you're
buying 2500', you'll get a better price, I hope.

Bob
One would think filling it with a fast setting epoxy / resin would be as
good or better and cost less.

Buy by the 55gal drum and inject.

When they installed a new telephone pole in my side yard - I have 1800
foot of 2-phase HV to the house and shop. :-) They had the pole set
and the hole a bit large but not much. Before setting, they dumped
a mixed up resin and poured it in the hole. Then dropped the pole and
another 5 gallons of the stuff was poured around it. The two men then
did heave plenty of dirt atop of the hole and stood atop that! They
rose by maybe 6" as the plastic resin expanded and filled every crack.
It also helps protect the pole from insects. No hidden holes to allow
the pole to lean after a rain storm.

Martin

Plastic roll pin
 

On 7/12/2014 11:52 PM, Martin Eastburn wrote:
One would think filling it with a fast setting epoxy / resin would be as
good or better and cost less.
...

I like it! 1" dia x 4" long = 3 cu in = 2 fl oz.

Plastic roll pin
 

On 07/13/2014 7:55 AM, Bob Engelhardt wrote:
On 7/12/2014 11:52 PM, Martin Eastburn wrote:
One would think filling it with a fast setting epoxy / resin would be as
good or better and cost less.
...

I like it! 1" dia x 4" long = 3 cu in = 2 fl oz.

The overall piece is 12" and this is a retrofit kit to existing
customers, too? Would take a plug inserted unless going to fill whole
thing. Cost of even a cheap epoxy??

Anyway, I'd wonder if they wouldn't be better off financially to just
scrap current inventory and go to a stiffer piece unless there's a very
large number in stock it could end up being cheaper than the
retrofit...unless they think this is really a long-term solution which I
wouldn't think would be the case, surely?

--