Follower rest usage question

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Bill Kahn

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I am a newbie. Have been enjoying my new PM1030. Tried the follower rest on 15" of 1/2" steel rod. 5" in the chuck.

Adjusted the top and back brass slidey thingies (sorry, just don't know the right word) so that they touched the top and back of the rod. And I took a skim pass. Seemed to work well. Went back for another pass. Well, after a few passes it dawned on me that the slidey thingies needed to be slid (down and in respectively) as I no longer had a half inch rod--maybe only a .48" rod.

I am missing two key ideas on how to use a follower rest:
1) Do you have to readjust them after every pass? (Seems like a pain, but seems to be needed)
2) At the end of the pass (when the tool is closer to the chuck) and after a few passes the brass slidey thingies are no longer on where you have machined the diameter down. How are they supposed to "ride-up" to the original diameter?

This is clear as mud. But maybe it is a standard problem and the experienced hands here will recognize my confusion. If not I can post a photo.

Thank you.

-Bill
 
Most follower rest you do have to adjust after each cut . It's a pita but it's what keeps the tool pressure into the cut not pushing several thousandth of material away while it's cutting. The only way not to is to only use it for the last or clean up cut.
 
I don't think you're missing anything. I look at a follow rest as a necessary evil that allows you to machine a long, thin and deflectable part with a fair amount of accuracy. I don't like to use them but sometimes you have no choice.

Yes, you do have to re-adjust the arms of the rest as you reduce the diameter. When you do this, just bring the arms into contact; do not push on the part.

If your part has a shoulder then you would use the follow rest to get close to the shoulder and then remove the follow rest and machine the rest of the shaft and shoulder after the follow rest is removed. Since the part is better supported up close to the chuck deflection is less of an issue. Or you can form the shoulder first and machine out toward the tailstock. This is how I threaded a leadscrew for a friend's cross slide. Its a pain but a necessary one sometimes.
 
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