project help


E A
 

All
I need to turn down three pieces of 1 1/4" dia stainless steel pipe to 30mm.
My first thought was to make a pair of steel "plugs" with center holes drilled, and then turn the pipe between centers.
The pieces of pipe will end up being cut down into shorter sections... some 4 1/4" long, some 1 3/4".
Turning between centers though seemed like it would result in less waste, be faster, and I can polish it as well right in place.
So, am I over thinking / underthinking this?
Suggestions would be apreciated!
Erik A


eddie.draper@btinternet.com
 

Seems reasonable. I would cut to length first, or turn pieces no longer than 2 or at most 3x the longest piece at one time, depending on how accurate you need to be. Longer will mean deflection and a barrel shaped product or the need for a steady.


You don't say how thick is the tube wall. Best to avoid gripping in a chuck unless you have a close fitting plug inside it, otherwise it will deflect under the jaws and you'll end up with the adjacent part of your tube lacking cylindricity in a triangular manner.


Eddie




------ Original Message ------
From: "E A" <b-arch@...>
To: "SouthBendLathe@groups.io" <SouthBendLathe@groups.io>
Sent: Tuesday, 4 Oct, 22 At 14:51
Subject: [SouthBendLathe] project help

All
I need to turn down three pieces of 1 1/4" dia stainless steel pipe to 30mm.
My first thought was to make a pair of steel "plugs" with center holes drilled, and then turn the pipe between centers.
The pieces of pipe will end up being cut down into shorter sections... some 4 1/4" long, some 1 3/4".
Turning between centers though seemed like it would result in less waste, be faster, and I can polish it as well right in place.
So, am I over thinking / underthinking this?
Suggestions would be apreciated!
Erik A


Todd
 

Most all "pipe" is seam welded and will have the same bump running its length as square does. This can cause issues as you will no doubt know.  I guess it all depends on what the final application is, possible variation in the desired thickness around the pipe and the amount of time and tooling you have to make this a worthwhile project.
 I would gently chuck the pipe and bore the i.d. on both ends to be as concentric with the o.d. as possible (use a 4 jaw) put an aluminum plug in the chucked end to keep from deforming and then use a cone center in the tail, then turn away.

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From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of E A <b-arch@...>
Sent: Tuesday, October 4, 2022 9:51:13 AM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: [SouthBendLathe] project help
 
All
I need to turn down three pieces of 1 1/4" dia stainless steel pipe to 30mm.
My first thought was to make a pair of steel "plugs" with center holes drilled, and then turn the pipe between centers.
The pieces of pipe will end up being cut down into shorter sections... some 4 1/4" long, some 1 3/4".
Turning between centers though seemed like it would result in less waste, be faster, and I can polish it as well right in place.
So, am I over thinking / underthinking this?
Suggestions would be apreciated!
Erik A


mike allen
 

        I think your on the right track . I try to turn between centers when ever I can They make live centers for pipe . or Joe Pi on youtube has a vid on making a live center that's real simple , just when you get to the center  part make it large enough to work with your  pipe . That way you get your project done & end up with a new live center .

        https://www.youtube.com/watch?v=vlPbDBLhwdc&ab_channel=JoePie

   

        animal


On 10/4/2022 6:51 AM, E A wrote:

All
I need to turn down three pieces of 1 1/4" dia stainless steel pipe to 30mm.
My first thought was to make a pair of steel "plugs" with center holes drilled, and then turn the pipe between centers.
The pieces of pipe will end up being cut down into shorter sections... some 4 1/4" long, some 1 3/4".
Turning between centers though seemed like it would result in less waste, be faster, and I can polish it as well right in place.
So, am I over thinking / underthinking this?
Suggestions would be apreciated!
Erik A


E A
 

Thanks all for the ideas! I should have mentioned the ss pipe is seamless, which should make fitting a plug easier.
It is 1/8" thick, and I will only be taking .034" off to go from 1.25 to 1.181...
With such a light amount to remove, I guess the trickiest part is going to be getting it VERY centered to start.
Erik A

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of Todd <belvedere66@...>
Sent: Tuesday, October 4, 2022 12:11 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] project help
 
Most all "pipe" is seam welded and will have the same bump running its length as square does. This can cause issues as you will no doubt know.  I guess it all depends on what the final application is, possible variation in the desired thickness around the pipe and the amount of time and tooling you have to make this a worthwhile project.
 I would gently chuck the pipe and bore the i.d. on both ends to be as concentric with the o.d. as possible (use a 4 jaw) put an aluminum plug in the chucked end to keep from deforming and then use a cone center in the tail, then turn away.

Sent from my Verizon, Samsung Galaxy smartphone
Get Outlook for Android

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of E A <b-arch@...>
Sent: Tuesday, October 4, 2022 9:51:13 AM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: [SouthBendLathe] project help
 
All
I need to turn down three pieces of 1 1/4" dia stainless steel pipe to 30mm.
My first thought was to make a pair of steel "plugs" with center holes drilled, and then turn the pipe between centers.
The pieces of pipe will end up being cut down into shorter sections... some 4 1/4" long, some 1 3/4".
Turning between centers though seemed like it would result in less waste, be faster, and I can polish it as well right in place.
So, am I over thinking / underthinking this?
Suggestions would be apreciated!
Erik A


wlw19958
 

Hi There,

One alternative idea would be to mount the section of
pipe on a mandrel. 

Good Luck!
-Blue Chips-
Webb


DJ Delorie
 

"E A" <b-arch@...> writes:
My first thought was to make a pair of steel "plugs" with center holes
drilled, and then turn the pipe between centers.
I'd do that for the tailstock end; chuck a 1 1/4" solid round in your 3
or 4 jaw, center drill it, and turn a step and 5 degree taper (facing
the headstock) just the right size to tight fit in the end of the pipe,
and part off. Now turn a matching step and 5 degree taper facing the
tailstock on the remaining stock and leave it in the chuck! It's
already perfectly centered and can act as a "turn between centers" jam
chuck.

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__-- --__ |
__-- --__ |
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------- --

If it were me, I'd cut the pipe to the various lengths first and then
batch turn the smaller lengths to diameter, to avoid chatter.


Mike Poore
 

You will get a different answer from everyone that replies because there is no right answer and it depends on your tooling and experience.

I would use a cone center on the tail. I would chuck a short 1 1/4" dia. piece of solid stock and put a taper in it slightly smaller than the id of your pipe. Leave it in the chuck so that you do not lose concentricity. Grind off the internal weld at the very end. The point of contact with the taper will barely go in the pipe. Removing too much weld will not affect anything. Too little will.

If you do not have a cone center, you can make one easier than making plugs.

On 10/4/2022 9:51 AM, E A wrote:

All
I need to turn down three pieces of 1 1/4" dia stainless steel pipe to 30mm.
My first thought was to make a pair of steel "plugs" with center holes drilled, and then turn the pipe between centers.
The pieces of pipe will end up being cut down into shorter sections... some 4 1/4" long, some 1 3/4".
Turning between centers though seemed like it would result in less waste, be faster, and I can polish it as well right in place.
So, am I over thinking / underthinking this?
Suggestions would be apreciated!
Erik A


E A
 

DJ, Mike
Those are some good ideas!
I think what you both are saying is it will jamb tight enough that no dog is needed?
Erik A

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of Mike Poore <mpoore10@...>
Sent: Wednesday, October 5, 2022 12:39 AM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] project help
 
You will get a different answer from everyone that replies because there is no right answer and it depends on your tooling and experience.

I would use a cone center on the tail. I would chuck a short 1 1/4" dia. piece of solid stock and put a taper in it slightly smaller than the id of your pipe. Leave it in the chuck so that you do not lose concentricity. Grind off the internal weld at the very end. The point of contact with the taper will barely go in the pipe. Removing too much weld will not affect anything. Too little will.

If you do not have a cone center, you can make one easier than making plugs.

On 10/4/2022 9:51 AM, E A wrote:

All
I need to turn down three pieces of 1 1/4" dia stainless steel pipe to 30mm.
My first thought was to make a pair of steel "plugs" with center holes drilled, and then turn the pipe between centers.
The pieces of pipe will end up being cut down into shorter sections... some 4 1/4" long, some 1 3/4".
Turning between centers though seemed like it would result in less waste, be faster, and I can polish it as well right in place.
So, am I over thinking / underthinking this?
Suggestions would be apreciated!
Erik A


DJ Delorie
 

"E A" <b-arch@...> writes:
I think what you both are saying is it will jamb tight enough that no dog is needed?
If the taper is shallow and the right size, and you take light cuts,
probably. Pressure from the tailstock will help. Otherwise, use a dog
and do one half at a time.


Richard Green
 

I'm surprised no one has suggested using a four-jaw chuck with internal gripping jaws. With a live cone center on the tailstock, you can turn the full length with ease.

On 10/4/2022 9:51 AM, E A wrote:
All
I need to turn down three pieces of 1 1/4" dia stainless steel pipe to 30mm.
My first thought was to make a pair of steel "plugs" with center holes drilled, and then turn the pipe between centers.
The pieces of pipe will end up being cut down into shorter sections... some 4 1/4" long, some 1 3/4".
Turning between centers though seemed like it would result in less waste, be faster, and I can polish it as well right in
place.
So, am I over thinking / underthinking this?
Suggestions would be apreciated!
Erik A
--
Rick Green


eddie.draper@btinternet.com
 

Wouldn't a 3 jaw work just as well?


Also, there is no circular support, so if gripped in a worthwhile manner, this is another way of turning a square or triangle shaped piece.


Eddie




------ Original Message ------
From: "Richard Green" <rtg@...>
To: "SouthBendLathe@groups.io" <SouthBendLathe@groups.io>
Sent: Wednesday, 5 Oct, 22 At 21:41
Subject: Re: [SouthBendLathe] project help

I'm surprised no one has suggested using a four-jaw chuck with internal gripping jaws. With a live cone center on the tailstock, you can turn the full length with ease.


On 10/4/2022 9:51 AM, E A wrote:
All
I need to turn down three pieces of 1 1/4" dia stainless steel pipe to 30mm.
My first thought was to make a pair of steel "plugs" with center holes drilled, and then turn the pipe between centers.
The pieces of pipe will end up being cut down into shorter sections... some 4 1/4" long, some 1 3/4".
Turning between centers though seemed like it would result in less waste, be faster, and I can polish it as well right in
place.
So, am I over thinking / underthinking this?
Suggestions would be apreciated!
Erik A

--
Rick Green








Richard Green
 

On Thu, 6 Oct 2022, eddie.draper@... via groups.io wrote:

Wouldn't a 3 jaw work just as well?
I suggested a 4 jaw because the OP said it was already thinwall tubing, so initial concentricity of the OD was important. The 4 jaw allows one to dial it in before turning.
Also, there is no circular support, so if gripped in a worthwhile manner, this is another way of turning a square or triangle
shaped piece.
The 4 jaw gives more friction area than a three jaw, so the pressure needs to be less. And if pressure is applied by the tailstock and cone center, this will reduce the need for deforming pressure on the headstock end.

Does anyone make a 6-jaw with inside grip capability?

--
Rick Green


John Byghtn3
 

Here are many economical 6-Jaw chucks...(And some expensive ones as well)

Good Luck


On 10/6/2022 8:36 AM, Richard Green wrote:

On Thu, 6 Oct 2022, eddie.draper@... via groups.io wrote:

Wouldn't a 3 jaw work just as well?
  I suggested a 4 jaw because the OP said it was already thinwall tubing, so initial concentricity of the OD was important.  The 4 jaw allows one to dial it in before turning.

Also, there is no circular support, so if gripped in a worthwhile manner, this is another way of turning a square or triangle
shaped piece.
  The 4 jaw gives more friction area than a three jaw, so the pressure needs to be less.  And if pressure is applied by the tailstock and cone center, this will reduce the need for deforming pressure on the headstock end.

 Does anyone make a 6-jaw with inside grip capability?