There are many ways to do this.A "D" nosed reamer threaded to a shaft is another.A rolling support spider with a cutter head will eliminate most chatter even on a small lathe.Balling a tube or hole will make it round and straight most times.The old world armory reamer using cigarette papers for adjustment will cut a true round straight hole in the longest tube.

While welded pipe may not be the best for high pressure calibers you can use it for pistol and some lower pressure ones.I have seen many pictures of blown tubes but none that burst on the seam.I know that some of the early titanium suppressors used welded CP-2 without problems.
-CL

When working with tubing on the lathe this is what I do to reduce squeal and chatter.
When cutting on the OD stuff a wet rag into the tube, packed in tight, and this will dramatically reduce chatter/squeal. When boring wrap the OD with a stiff modeling clay, 1/4 in is enough, then secure with a wrap of wide tape - watch your spindle speed to not throw off the wrap. The clay will prevent any chatter/squeal in the tubing but not reduce chatter from a insufficiently stiff (thick) boring bar. There is no substitute for a stiff and thick boring bar.


Does anyone know where I can buy 17-4 SS tubing (1.5in OD) in smallish quantities (6ft)?

Has anyone used a tuneable boring bar before?
I've seen one and heard about their success, but never used one personally.

CMV wrote:

Capt. Link. wrote: I use seamless pipe then turn and bore it to size.http://www.onlinemetals.com
-CL

What kind of boring bar & setup do you use for that? I tried a few different boring bars, placing a bunch of O rings around the tube OD, all kinds of different feed rates & RPM, feeding both directions, but no matter what, I'm getting all kinds of chatter & poor results trying to bore an 8" tube.

Reduce the cutting area of your tool bit; sounds like you have too much contact for the stiffness of your boring bar. If it's insert tooling, get inserts with the smallest radius tip you can. If HSS or brazed carbide, sharpen it to a point, then just break the edge a little. More contact area = more chatter

Rich V wrote:When working with tubing on the lathe this is what I do to reduce squeal and chatter.
When cutting on the OD stuff a wet rag into the tube, packed in tight, and this will dramatically reduce chatter/squeal. When boring wrap the OD with a stiff modeling clay, 1/4 in is enough, then secure with a wrap of wide tape - watch your spindle speed to not throw off the wrap. The clay will prevent any chatter/squeal in the tubing but not reduce chatter from a insufficiently stiff (thick) boring bar. There is no substitute for a stiff and thick boring bar.


Does anyone know where I can buy 17-4 SS tubing (1.5in OD) in smallish quantities (6ft)?

http://www.tubehollows.com/alloys/stainless-steels/17-4
We machine custom 17-4PH tubing in sizes from smaller than 1” OD to over 5”.

fastfire wrote:

Rich V wrote:When working with tubing on the lathe this is what I do to reduce squeal and chatter.
When cutting on the OD stuff a wet rag into the tube, packed in tight, and this will dramatically reduce chatter/squeal. When boring wrap the OD with a stiff modeling clay, 1/4 in is enough, then secure with a wrap of wide tape - watch your spindle speed to not throw off the wrap. The clay will prevent any chatter/squeal in the tubing but not reduce chatter from a insufficiently stiff (thick) boring bar. There is no substitute for a stiff and thick boring bar.


Does anyone know where I can buy 17-4 SS tubing (1.5in OD) in smallish quantities (6ft)?

http://www.tubehollows.com/alloys/stainless-steels/17-4
We machine custom 17-4PH tubing in sizes from smaller than 1” OD to over 5”.

Thanks fastfire
They make their tubing by drilling from solid rod, it will be very expensive.

I'm looking for a place that sells in smaller quantities of extruded seamless 17-4.

Well, I made a plug .004 bigger dia. and 3" long than the I.D. and pressed it through the tube to straighten it. It got within .008 of being straight but not good enough.
I've made 4 orders of seamless tubing from online metals with none of it straight enough to make a suppressor.

Now I guess I'll bore out a 416 solid rod to get what I need.

What size are you needing? I have some extra stainless tube but would have to go look & see what size. somewhere between 1 1/4 - 1 1/2 I think.

CMV wrote:What size are you needing? I have some extra stainless tube but would have to go look & see what size. somewhere between 1 1/4 - 1 1/2 I think.

1 5/8" thanks

I have a 40mm spindle bore so I tend to stick to 1.5" OD. I think I have some 4130 that size. If you're not dead set on SS, Stock Car Steel has really good seamless 4130 that isn't at all expensive.

But I'll look & see what I have....

CMV wrote:I have a 40mm spindle bore so I tend to stick to 1.5" OD. I think I have some 4130 that size. If you're not dead set on SS, Stock Car Steel has really good seamless 4130 that isn't at all expensive.

But I'll look & see what I have....

Thanks, but I am set on SS.