Steady Rest principles.

Back again, lots of questions at the mo.

I need a larger mini lathe steady rest than is available commercially.

This has been on the 'to do' list for a while. Time to do.

As i'm going to have to make one may as well make it with circa 4.5" capacity to cover all bases.

I see Hemmingway do a kit for a 5" myford rest that could probably be adapted.

& There are numerous exam[les of DIY rests on the net.

However, i'm thinking K.I.S.S. ,I't doesn't need to be a work of art,It just needs to do the job.

I could spend weeks/ months making the mother of all mini lathe steady rests, but why?

I like the idea of brass fingers, but brass tipped bolts is simpler.

I like the idea of a cast iron body , but that's slower work than Aluminium.

My questions are namely thus~

Are steady rests subjected to any great load (in a home shop environment)

&

Would any vibration damping offered by cast iron be worthwhile/ noticeable on a hobby machine?

Thanks.

Hi Samuel you don't say what lathe you are working on and what steady you would like to make. I think you are looking at a fixed steady and i prefer cast iron as it has good stability. My steady for my Myford M Type has a cast iron body with screws with phosphor bronze tips to prevent wear and damage to the job you are turning. Aluminium is too light for a steady in my thinking but I have seen steel ones which were fabricated and very stable. There are possibly very large loads on a steady like, I somtimes put a long bar in my lathe and part off a length when the bar will not go down the spindle.

David

Simple way to get a big one for your Minilathe is to buy one for a larger far eastern lathe, chop the bottom off and then make a suitable "foot" to fit it to your lathe though than won't give the 4.5" dia capacity

Will it be your only steady rest? Or will you use it when the capacity of the OEM one is inadequate?

In your orignal post, you only quote a maximum capacity, so your design parameters are at best only 50% defined.

If you want it to range from 4.5 inch diameter down to nominally zero diameter, the adjustment screws will be very long. They will stick out a lot at maximum capacity and might be slender and whippy (totally negating any benefit you gain from whatever body material you choose) at minimum capacity.

Hence, I would say there are more pressing decisions to be made at this stage than body material.

.

I suggest you have a look at Steve’s thread, here: **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=184158&p=1

.

and maybe start a P.M. discussion with him.

MichaelG.

Something like this from a piece of thick wall tube would not need much work, either with the flat fingers shows or drilled for round or threaded fingers.

Regarding DC's point you could always have a reducing ring that slipped inside the larger ring and held by grub screws then use the existing fingers on the reducer

If you can weld, then a steady rest is easy to make from some thick wall tube and bar and some fitting.

Some years ago John Stevenson showed how he made large steadies from bolting laser cut pieces together, which is quick, easy and frugal.

Long fingers are inevitably floppy and making a nice solid job of the fitting is more work than you might initially expect. Simple screws are always too floppy. There is a reason why so many lathe makers use a separate slider and adjustment screw.

My Smart & Brown 1024 has a simple L shape lump of bronze for the support member on the travelling steady. The internal angle acts as a simple Vee support simultaneously holding the job against cutting loads in both axes.

Maybe something similar would work as a substitute for two of the fingers on a large three point steady with a suitably solid finger providing the third support. I imagine that clearance issues would restrict the size range so you'd need more than one to cover the full range. But how hard is it to cut a Vee out of a piece of plate.

Alternatively a couple of small ball bearings ought to work just as well as a V cut out. (Cue 600 post discusiion as to weather bearings are better than pads!)

Should I ever need to make a large steady I'll try doing it that way. I have a vague memory of seeing a picture or published design along these lines, possibly based on two steel rings welded together with suitable spacers between.

Clive

Just as a matter of naming, I thought what is being described is a fixed or travelling steady. But a "steady rest" is for hand turning isn't it?

The Hemingway kit large steady is aluminium castings, so they must do the job. Probably good enough for a mini lathe. But Jason's suggestion of cutting down a steady from a larger Chinese lathe would be better and easier I should think.

If you make your own, yes large diameter screws with brass tips work ok. I made one for my Drummond and went a bit overkill, cutting it out of 1" steel plate and using 9/16 UNF Grade 8 set screws for the fingers with brass tips. Only thing is the tips can get a little concave hollow worn in them so when you turn the screw a fraction to tighten up the finger, the hollow swings around and takes up more slack than you really expect. But it does not seem to stop the whole thing from working very well.

Making a larger steady is on my Round Tuit list. Probably will use the same type of screws but fabricate the body out of thick walled square steel pipe or maybe a bit of thinner steel plate, say 3/8" with bosses welded on for the fingers.

Sam is asking the right questions, and sets the scene quite well with 'It doesn't need to be a work of art,It just needs to do the job.'

The answer depends on what the job is! How big, how heavy, and how quickly must metal be removed?

Steadies are a good thing whenever a long sticky-out has to be done. Three main functions I think:

• To stop the job moving during cuts, thus avoiding poor finish, tapering, and parting-off dig-ins.
• To reduce chatter
• To stop jobs whipping and/or levering themselves out of the chuck. These are in the top five most dangerous things you can do on a lathe!

These require a certain amount of beef, partly to take the mechanical strain and partly to absorb vibration. Aluminium is strong enough, but being lightweight, it's not good at preventing chatter. If it occurs the operator has to adapt with a lighter cut, different cutter, or whatever. Cast-iron is weaker than Aluminium, but better at absorbing vibration. Both work, as does wood when the devil drives. After that details: square brass fingers are better than screws, but screws are easier to make. They're not as good as fingers because they vibrate loose and develop awkward grooves.

Once you get through the outer skin, which is common to castings, cast-iron generally machines well. The problem is it's filthy dirty and the mess goes everywhere!

Dave

Do you mean something like this,Clive?

Pretty poor quality pictured, snipped from the YouTube video that I made of the accessory.  A clearer and fuller description is in the video itself and there's a write-up in MEW, too, issue 287 November2019 pages 9 to 15 . The capacity goes from about Ø5mm to a smidgen over 90mm. I used the ball bearings as an experiment and the swinging arm arrangement for the adjustment was chosen to combat the "long finger" problem mentioned above. The steady featured is a travelling one but a similar design would be equally suited to a fixed version. In fact, using the ball bearings would be better suited to a fixed rest, in my opinion.

John

Edited By John Hinkley on 19/01/2023 14:05:53

Thankyou to all for the input.

Appreciate Hopper advising to use thickish bolts... I was thinking M8, glad that got nipped in the bud.

Still weighing up the possibilities.

Need to hold fire on the questions & get some stuff made now i think.

I tried with bearings but they lock up under pressure, the best solution I found for heavier work was bronze fingertips and a bit of lubrication

I managed to get 7/8ths of a large capacity myford steady from RDG, I missed out when they were selling them at a show and rang them on the off chance later. They very kindly sold me the last one they had which was incomplete at a good price and I made the missing bits (one finger and a couple of screws). It is an aluminium casting for the body and it’s been fine, I bored the cast iron cylinder liner for my 6” scale traction engine using it on the S7 (3” bore). Used it for lots of other stuff too and it’s been fine so I don’t think aluminium would be a problem.

Paul.

At risk of being pedantic - we must get the terminology right ! A, it's a steady, 2 point, often travelling or 3 point, fixed. Or B it's a rest ! It can't be both ! If welding is an option then a lump of heavy gauge tube, nuts and set screws tipped with brass or bronze will make a simple 3 point steady in steel, probably stronger than cast iron. Noel

As you say, doesn't have to be a work of art ! I usually get the plastic faced bearings a nice running fit on the job before finally tightening the large clearance bolts at the bottom. Fits my Super 7.

That just needs a coat of paint to move into the much better than it needs to be and I thought was going to be category

ChrisLH:

What plastic did you use?

I suppose oil-filled nylon might be a good choice.

I saw a steady rest that had an extra slide that was at the back, close to the centre height. It was intended for big pieces when taking a fairly large cut when roughing down an outer diameter. He said that the front one the top one and this added one was all that was needed and the back bottom one he seldom used. I have not tried to figure out if true, but was told that it averaged out the roundness of the stock better resulting in a more round part being cut.

The advantages of cast iron is quite easy to cut when making things from it, and is alot more rigid than cast ali or mild steel. I like Jason's idea of getting a casting of one existing and reworking to suite. It sounds like you have the standard one that comes wit the machine, so it only has to cover outside that to the 110mm or so in diameter.