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Follow rest

ShawnR

ShawnR

Ultra Member
Premium Member
In preparation for an upcoming project of profiling a long tube, I thought I might practice a bit with a follow rest. Material is just hot rolled steel, about 1.25" diameter. I have tried with HSS and carbide, new insert, different insert, and sharpened the HSS more than once. I am still managing to get chatter. Cuts with HSS have been down around 0.003 to start. I ground the rust/scale off of the piece to keep it off my lathe so now I just want to see what kind of setup and process I need to get an acceptable finish. I don't know what to expect.
The piece is between centers (new technique to me too) Perhaps my centers are not deep enough?

I am hoping for some input/suggestions to try. I did not spend a lot of time yesterday at it, just kinda getting started. I hope to experiment more today. I thought I should get that technique down before I risk damaging that expensive tube I have to turn down. :rolleyes:
 
Only about a month and a half and we get to have some fun!!!

How long is your piece of 1.25? 3 thou on a cut might suggest you need a tweak in the tailstock - dial that in, and then run a light pass. Your “grinding” of the piece may also be causing some issues as it runs against the follow rest bearings.
 
Hey Brent!! I am building my list of things to get your personal assistance on! :-)

The piece of stock is about 20 inches long. My follow rest runs on the cut section (behind the cutter, relatively speaking) so I think it should be good, no? I cut a section next to the tailstock until the rest will ride on it. My rest has bearings in it. I am not sure how firmly to adjust those against the stock. Again, messing with different cutters yesterday, I may have caused some issues too. I probably need to work on my bit grinding skills too. I will post some setup photos later. I have not googled follower rests much. I know that all of the popular youtubers have demonstrated it in their videos. It is not usually a stand alone video though so I am guessing it will be a hit and miss to find it.

My 3 thous comment was my depth of cut. I am thinking it is a light cut. At that rate, my project, when I tackle it, will be a very slow one! But after running a few good passes, this will allow me to determine my tail stock alignment. (only to move it later for my project.....) lol
 
ShawnR said:
Hey Brent!! I am building my list of things to get your personal assistance on! :-)

The piece of stock is about 20 inches long. My follow rest runs on the cut section (behind the cutter, relatively speaking) so I think it should be good, no? I cut a section next to the tailstock until the rest will ride on it. My rest has bearings in it. I am not sure how firmly to adjust those against the stock. Again, messing with different cutters yesterday, I may have caused some issues too. I probably need to work on my bit grinding skills too. I will post some setup photos later. I have not googled follower rests much. I know that all of the popular youtubers have demonstrated it in their videos. It is not usually a stand alone video though so I am guessing it will be a hit and miss to find it.

My 3 thous comment was my depth of cut. I am thinking it is a light cut. At that rate, my project, when I tackle it, will be a very slow one! But after running a few good passes, this will allow me to determine my tail stock alignment. (only to move it later for my project.....) lol
Click to expand...
I might have missed a lot, but, if I was looking for 3 thou and surface finish was of paramount importance I would grind a shear tool and take it in 2 or 3 passes.
 
I think my post was a little confusing. I was only trying cuts as small as 0.003 to try to alleviate chatter. Nothing helped with chatter. Overall I have much more to remove. I think I will explore other options that have been suggested to me. Steady rest, step cutting, etc.

Perhaps I will report back....or might just hide my head in the sand. Depends on success. ;-)
 
A follower rest with rollers? Humm, I’ve never seen one like that, please post a picture of your set up. I have only ever seen/used them with buttons, which will better manage the chips.

0.003” DoC on 1.25” dia over 20” should be no problem even with out additional support. It sort of feels like something else is going on. Consider using an insert threading tool, something with a bit of nose radius (not full point, perhaps 16tpi), of course a fairly fine feed rate - that way there will be very little tool edge engagement (thus less tool push).
 
Sort out the finish and cutting details while still cutting in our scrap material. Seems like something is going on there. Let us know how it works out.
 
I'm with @140mower Shawn. A really sharp shear tool will cut 3 thou nicely with good finish and no chatter.

But I wouldn't hesitate to try a bigger cut. Sometimes more is less. Also try a round edge - less likely to chatter and usually makes a good finish too. Adjust feed rate to improve cut.

Wish I was there. The cutter and the work will both talk to you if you know their language.
 
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