Thread: steady rest fun

Been trying out the new steady rest .

First attempt . Threading a 1/2 bar to 8 tpi . It was going great until the saddle ran into the vernier calipers I left on the bed and it jammed up everything , the tumble gears disengaged and saved the day . Unfortunately , this accident has thrown out the screw cutting settings and I lost the plot ..

2nd attempt is turning down a bar to 1/2" .... The first cut is shallow over a 14" length, I have a 1 thou difference over that length , I checked this with the Moore and Wright micrometer .

Still learning MIKE

Mike
Good work,well done on the accuracy.
I was thinking about your left hand thread as I was working in the workshop this afternoon.
It goes without saying but its best to start a left hand thread by machining a starting groove, down to the minor dia of the thread you are about to cut.
You are probably aware of this but I just thought it was worth a mention.
All the best, one never stops learning.
Your lathe bed slideways appear to be in good condition, from your photo.
regards
Bruce

Hi Bruce

I will take on your advice next time . The follow rest ( not steady rest ! ) is a Hercus part but it fits the Sheraton OK . It's little close to the front way , and it could do with some slight adjustment .

I only had one piece of 1/2" rod that I salvaged from an old printer . I hope to make a new cross fed screw for the other lathe (acme 8 tpi ) . Sadly, I stuffed up that one piece of 1/2" rod ( silly mistake ) , so I need more 1/2" rod to play with . Would 303 stainless be a good choice ? Only thing is , I can only find 12mm rod locally , and It needs to be 1/2" MIKE

Not really.

Originally Posted by morrisman

The follow rest ( not steady rest ! )

Hi mike
I have always called them fixed or traveling steadies.
But then as my old boss used to say, "it depends on whether you were educated at Yale or Harvard"
I apologise in advance.

Phil

Originally Posted by pipeclay

Not really.

OK I might use 12L14 then , at least I can get it in 1/2" . With the amount of use the lathe will be getting , I would think that it would last a long time . Or, an alternative might be 1/2" drill rod . MIKE

12L14 will be much easier to thread and so I'd chose that first, if only for practice. Drill rod is heat treatable so may tend to get harder on you if you get it hot (blunt tools etc)

Michael

Mike
I would go for the 1/2" Mild steel
With good lubrication, it will outlast you, & its a pleasure to machine particularly for screwcutting. If you mess things up just keep persisting, it does not matter.
regards
Bruce

Hercus made their mill feed screws from 1214 ( as per a conversation I had with Steve Durden at F W Hercus 3 years ago).

BT

Originally Posted by Anorak Bob

Hercus made their mill feed screws from 1214 ( as per a conversation I had with Steve Durden at F W Hercus 3 years ago).

BT

Thanks BOB .Good to know what is the correct material. I have made some progress I think. I have used the same piece of rod salvaged from the printer . I managed to pick up the thread again and do some more cutting . I first tried a thin parting off tool, but it flexed too much . Instead, I ground a thin tipped HSS tool up and it works OK for the roughing cuts . I plan to use the 8 tpi ACME cutters I bought from FLEABAY for the finishing cuts ... These cutters have a 90 degree base , so I will have to mill up a holder for them to fit my tool post . I suffered a disater when the tool jumped out of the groove and messed the therad... this was caused by the follow rest being incorrectly positioned ... I managed to find the groove again and rescued the thread MIKE Bear in mind this is my first attempt at this kind of job..The correct depth for a 8 tpi acme is .0725" ..I have it at .060" with the roughing tool.......I noticed the middle was cutting shallower that the ends , probably because my follow rest wasnt set up correctly .

I found I had to fine tune the tailstock alignment to get the follow rest bearing evenly along the length. I mainly tuned it by ear - by listening to the dragging sound as I rolled the carriage along - and then verified with an indicator.

I believe in general a follow rest is supposed to follow the tool, so it bears on the freshly cut diameter. Of course this is irrelevant when screw cutting as you're not reducing the diameter.

Originally Posted by Bryan

I found I had to fine tune the tailstock alignment to get the follow rest bearing evenly along the length. I mainly tuned it by ear - by listening to the dragging sound as I rolled the carriage along - and then verified with an indicator.

I believe in general a follow rest is supposed to follow the tool, so it bears on the freshly cut diameter. Of course this is irrelevant when screw cutting as you're not reducing the diameter.

YES Ok Bryan ..I think I erred in not having the tool close enough to the follow rest , the tool holder I use gets in the way though . Yes I did hear the rest making some grinding noises as it ran along the shaft .... As the tool jumped out of the groove it bent the shaft , I had to tap the shaft to get it concentric again. MIKE

Originally Posted by Michael G

12L14 will be much easier to thread and so I'd chose that first, if only for practice. Drill rod is heat treatable so may tend to get harder on you if you get it hot (blunt tools etc)

Michael

You wont harden drill rod by using a blunt tool on a lathe
it needs to be heated cherry red and quenched in either oil or a brine solution depending whether it's O1 or W1 .
Actually silver steel or drill rod (unhardened )as you call it would make a decent lead screw ,It's easy to machine and threads nicely in the lathe. No need to harden it at all .
Kev.

I managed to finish it ... 1/2" ACME screw 8 tpi ... Not bad for a first attempt . I milled a 90 degree V into the 3/8" square bar and mounted the ACME cutter in it .

Well done Mike.