Lathe Steady Rest Fingers

Project started on 2011-12-03

Project completed on 2011-12-22

My esteemed friend and colleauge Adam Trumpour recently bought a Standard Modern lathe for his rocket work. It came with a steady rest but the steady rest was lacking in fingers. A friend in need is a friend indeed. So, I agreed to help him make some fingers for his steady rest. 3 types of fingers were made:

  1. Solid brass
  2. Small ball bearing (so that it will fit inside the finger housing
  3. Large ball bearing (for heavy duty uses)

The steady rest takes 1/2" fingers. You can tell by looking at the finger housings. All fingers were made to match this.

Solid Brass

Nothing says tradition like have a set of good old solid brass fingers for your steady rest. This is the first set of fingers that I made.

Start off by cutting off a piece of free machining brass (C360).

Cutting a piece of brass

Chuck it into the lathe.

Brass bar in lathe chuck

Face and chamfer.

Facing a brass bar

Faced and chamfered

Faced and chamfered brass bar

Flip it around and put a 60° included angle on the other end with the compound slide.

Cutting a point on a brass bar

Take the bar out a little bit and clean it up.

Cleaned up brass bar

Put it in a vise and mill out some keyways for the screw.

Milling some keyways

This is what it looks like completed compared to before starting.

Before and after milling keyway

Do the remaining 2.

Brass bar with swarf

And here are the 3 fingers. You can already see the mark left by the screw when I tried installing them in the steady rest.

3 completed brass fingers

Its time to make the pushrod that extends the fingers out of the housing. We start by chopping a 5/16"-18 coupling nut in 2.

Coupling nut cut in 2

Next, we cut ourselves a bit of 5/16"-18 threaded rod and clean one end of it.

Threaded rod

Put some thread or locker on the clean end

Threaded rod with thread locker

Put the two pieces together. The thread locker will take a few hours to cure. It is a good idea not to touch the assembly much during this time.

Threaded rod with coupling nut joined by thread locker

Once everything is ready, you can put everything in place. Looks good!

Completed steady rest with solid brass fingers

Small Ball Bearing

These fingers have small ball bearings. These bearings are small enough so that they can retract into the finger housing, allowing for larger workpieces to be turned inside the steady.

Start off by cutting a piece of 1/2" steel. I used 1018 mild steel.

Steel rod

Chuck it in, face, chamfer and clean up like what we did before.

Cleaning up steel rod

Make 3 of these

3 steel rods

Chuck it into the milling vise.

Steel rod in milling vise

Touch off with an edge finder on the fixed jaw of the milling vise.

Edge finding on solid jaw of milling vise

Touch off with an edge finder at the end of the steel rod.

Finding the end of the steel rod

Now that we know where the steel rod is, we can mill out the flats.

Milling out flats on the steel rod

Spot and drill the hole that is going to support the ball bearing.

Drilling a hole

Chuck it in vertically so that we can mill the slot that the ball bearing will sit in. Note that there is a 1/4" lathe tool bit sitting in the vise. This is pressing against the flat that we just milled in the steel rod. This will help us get the slot parallel to the flat.

Setup for milling bearing slot

Mill out the slot.

Slot being milled out

Tap a hole to accept the retaining screw.

Tapping a hole

Once again, make 3 of these.

3 fingers made

The inner bearing race needs to be held away from the finger so that the outer race can spin freely. We are now making the washers to provide this gap. Spot the hole first.

Spot a hole

Drill a hole, turn down a sholder and part it.

Drilling a hole

This is what the washer looks like when installed in on the bearing.

Washer installed on bearing

Install the fingers into the steady rest and this is what you get.

Steady rest with small bearing fingers installed

Large Ball Bearing

For heavy duty work, the small bearings may not stand up the higher forces. So, a set of fingers were made with heavier duty and larger ball bearings.

The build process for these fingers are very similar to the small ball bearing fingers. So, we will skip most of the steps. Here we are spotting a hole for the bearing to be attached to.

Spotting a hole on a mill

Now we make the washers and nut that will retain the bearing. Here we face a steel rod.

Facing a steel rod

Spot a hole.

Spotting a hole on a lathe

Drill the pilot hole for the tap and tap an internal thread.

Drilling a hole

This is what the nut and washer looks like by them selves and when installed.

Ball bearing with mounting hardware

This is what the steady rest looks like with the large bearing figners installed.

Steady rest with large ball bearing fingers

Thats all there is to it. Here are all 3 different types of fingers side by side.

3 different types of steady rest fingers

This page was last revised on 2012-06-18.

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