Large Steady Rest

jbolt

jbolt

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Dec 3, 2013
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The steady rest that came with my PM-1440GT lathe only opens up to a little over 2". With shorter fingers I can get up to 3-1/4". I want to be able to work on larger diameter tubing so a larger steady rest is in order. The max swing over the cross slide is 8-3/4". My current design will allow up to 8".

I looked at various DIY steady rests, some over the top and other pretty awful. I don't think I need the rigidity of a steady made from solid steel or cast iron. I saw some fine examples of solid aluminum steady's but anything solid creates a lot of waste and makes the material expensive.

My current direction is to use 1-1/2" square tubing with 1/4" wall thickness for the frame. The base and clamp will be 1018 cold rolled steel along with the hinge and lock. The finger sleeves will be from 1-1/4" round 4130 and the fingers and finger jacking screws will be from O-1 drill rod. There will be two sets of fingers, one with bearing bronze tips and one with bearing tips.

Progress so far.....

Frame material rough cut.
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These are the finger sleeves cut to length, drilled and reamed for the fingers. Instead of drilling and boring to a shoulder for the finger jack screw to push against I drilled and reamed a through hole and then counter bored the top of the sleeve. A donut is pressed in that will also get welded.
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That is going to be one serious steady rest, Jay! Isn't it curious that the manufacturers of our lathes don't make these rests with more capacity? Looking forward to seeing this one completed.
 
mikey said:
That is going to be one serious steady rest, Jay! Isn't it curious that the manufacturers of our lathes don't make these rests with more capacity? Looking forward to seeing this one completed.
Click to expand...

I don't expect a manufacturer to provide a steady that will use the maximum clearance capacity of the lathe but it's a bit disappointing when the factory steady doesn't open any more than the spindle bore. The stock steady has the capacity to hold more but not without having to manufacture shorter fingers. It would be nice if the factory steady was at least optimized to use it's full potential.

The best part of this project is it is a good excuse to buy a few more tools....Oh and a TIG welder. :grin:
 
More progress. Worked on the hinge and latch parts today.

The pressure switch on my air compressor went kaput half way through running parts on the CNC mill. I need air for the pneumatic draw bar so I had to finish them on my heavy duty drill press. I didn't have a proper radius cutter in the size I needed for the hinge parts so I improvised and used a carbide round over router bit. Not recommended for steel but if used carefully it will work. I cut and ground off most of the material and then used 0.004" passes to finish.

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The hinge halves were clamped in the vise together to get drilled and reamed for the hinge pin. I used a couple of layers of masking tape in between the top and bottom of the hinge parts to allow for paint.

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Today's parts

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More progress....

Drilled the holes for the finger sleeves using a 1" annular cutter.

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Here is the setup on the CNC mill for cutting the slots for the hinge and latch and chamfering for welding.

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Tubing finished ready for welding.

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Next up is to make the fingers and jack screws.
 
GoceKU said:
looks nice Jay, you've put a lot of thought in the planning and machining, what's your plan to run brass feat or roller bearings?
As for the jack screw i may suggest straight 0.5 knurling my factory study rest has it and is easy to grip, i like it so much i've used it on my drill press build, link: https://www.hobby-machinist.com/threads/shop-made-homemade-drill-press.60639/page-2
Click to expand...

That's quite the project you have. Nice job.

As for knobs I found some cast aluminum knobs that I like the looks of. They will need some modifying to work so it will be a fun challenge to hold them for machining.
 
More progress....

Worked on the fingers. The fingers are made from 3/4" O-1 drill rod. I don't have an over sized reamer so the finger sleeves were reamed at 0.750". The drill rod is not precision ground so the tolerance is -0.000" +0.002". For a nice slip fit I turned the finger to 0.748" using a freshly sharpened and honed HSS tool bit. Here the fingers have been drilled but not tapped and are held between centers. The compression friction has enough grip for the light skim pass.

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A quick hit with some 320 paper removes the tool marks.

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For the jacking screws I had originally planed on single point threading them out of a solid piece of stock. With 4" of 3/8-24 thread I changed my mind and decided do it in two pieces. I'm using grade 8 all thread turned smooth on one end with a hat collar. All but 0.3" is turned for a slip fit and the last part for a press fit.

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The all thread shaft is held short for tig welding.

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Some time back I had picked up an import live center with interchangeable points from Victor Machine. This was a good project to finally use it to support the end of the all thread for turning. The first one cut fine but on the second part the live center stopped turning and the small point friction welded itself to the all thread. Needless to say I am less than please with the product.

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To finish the fingers I still need to tap the ends and cut the anti-rotation slot.

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