Steady rest pros and cons

[calstar]

What are the pros and cons of the two styles of steady rest, the "open " and "closed"? Which do you prefer and why?

thanks, Brian

 

[Terrywerm]

You will usually only see the open style on smaller lathes. I don't know that there are necessarily any pros or cons to either, but I suspect that the open type lacks some strength when in use. Keep in mind that the 'closed type' can be opened to insert or remove a piece of stock. I do suspect that the closed type actually has a larger opening for admitting or removing stock than the open model does.

As for preference, I really have none. Of the lathes that I used that had steady rests, both had the closed type. The closed type also seems to be the most common, and I suspect there is some sound reasoning behind that, I just have never known for sure what it is.

I do see one advantage to the closed type, though. You can open it to remove or insert a piece of stock without changing the settings of the fingers, whereas with the open type you have to back off at least two of the fingers to remove a piece of stock, then have to reset them after inserting another piece.

 

[calstar]

I do see one advantage to the closed type, though. You can open it to remove or insert a piece of stock without changing the settings of the fingers, whereas with the open type you have to back off at least two of the fingers to remove a piece of stock, then have to reset them after inserting another piece.

This is exactly the kind of feedback I'm hoping for terrywerm,

thanks, Brian

 

[Ray C]

I can't really comment about the pros/cons of the different styles of rests as, I've only used the types that fully enclose the piece. One thing to mention though is that using them is a little tricky. Almost always, the piece will loosen up from the jaws of the chuck so, Please... stop the machine once in a while and verify the jaws are tight. The issue is that it's very difficult to get a piece perfectly aligned when using a steady rest. As a result, the piece is rotating in a "cone" shape and this usually causes the jaws to loosen-up or, more likely, the stock metal in-contact with the jaws rubs down; and this causes the grip to loosen-up... Just a quick heads-up on that nasty little reality... You really don't want a piece of metal coming loose from the jaws -could be really bad for you and certainly bad for the machine.


Ray

 

[British Steel]

Yep, things can walk out of the jaws if the steady's not on Centre - easy way to get 99% there is to indicate in at the jaws, then a couple of inches out. Now slide the steady up to where you're indicating and adjust the fingers WHILE WATCHING THE DTI, finally loosen ONE finger and slide into place, then readjust the finger you loosened - I've done it this way for years (when possible), haven't has a part walk yet!


EDIT: the part can't rotate in a 'cone' as both ends are constrained, Chuck at one end, steady at t'other, what it does is rotate at an angle to the spindle axis, so it frets against the jaws and works its way out.

 

[itsme_Bernie]

I think Ray was saying that the part -wanted- to be rotating in a cone, if it wasn't in the steady rest, and that was why it worked it's way out.

Bernie

 

[Don B]

The solid ones that open are very handy if doing multiple parts, if possible use the center and the tailstock to setup the steady then move the tailstock out of the way.)

Edit: just as a side note on the big stuff we used a dedicated 4 jaw with a center in it for setting up then both ends could be dialed in, set up the steady, remove the 4 jaw and go to work.

Edit again: beer haze is fading brain is slowly kicking in, if your using the tailstock to set up your steady and the center is out you can use shims between your center and work piece to dial in your work, one other way if it's not possible utilize the tailstock is to use a short piece of stock turn it to the diameter the steady will be running on, set the steady on that piece close to the chuck, then the steady can be slid to where it will be used.

 

[Ray C]

I think Ray was saying that the part -wanted- to be rotating in a cone, if it wasn't in the steady rest, and that was why it worked it's way out.

Bernie

I misspoke but that's my fault... The concept and notion of what's taking place was conveyed. The truly main issue is safety. It's common for this setup to cause the workpiece to loosen-up from the jaws -and that's never a good thing.

I don't use a center support all that often but when I do, it's usually for a piece of raw stock that has scale and the outer diameter is anything but smooth and even. I once made 24 pressure rollers for a laminating machine. The finished bars were 4.5" diameter (1045 material) and Rockwell hardened to 45 C. Everything was cut in the as-is hot rolled condition and finished in a second pass. During setup, I used a flap sander wheel and wire wheel to get the scale off. The outer diameters varied a good 0.01" or more. In this condition, it's next to impossible (take that back, it's outright impossible) to setup the piece straight. In all cases, I setup as best as possible, spinning very slowly and cut enough to make the end round then, flipped it so the piece could be held properly in the jaws followed by making another end cut to make the diameter even. Next, I positioned the rest on the even part making adjustments in the fingers until it was reading true. This involves intentionally loosening and re-tightening the jaws to let the grip relax enough to adjust to the new rest adjustments. Finally then, I could drill a center hole.

The pieces were 28" long (just barely fit inside the heat treating oven) and required no more than 0.001" diameter runout from end to end. It was a multi-ton high speed, high pressure laminating system.

There are many conditions and circumstances when setting-up pieces like this and there are also many ways of skinning a cat. -The end game is safety, meeting the specifications -and turning a profit on the job.

Ray