Steady Rest Rehab + a New Steady Rest Casting

[vtsteam]

This is a steady rest I bought quite a while ago for $15 at a flea market. Back when I was building my new lathe, I tried to use it by adapting the base. But I eventually gave up on the steady rest as too much of a rehab project in itself, and shelved it for another day. Well that day has come around.

I'm not sure what lathe it was originally intended for. It  had a single prismatic slot on one side of the base and a flat on the other but I sawed off the base to fit the new lathe. It was, in my opinion, poorly made. The fingers were all unmachined castings with the draft taper left in place, making the tops wider than the bearing faces. The slots for the clamping screws weren't machined either. The slots weren't long enough to give full range of travel.


There was just some evidence of crude belt sanding of the fingers to fit their individual slots. They didn't all come together evenly or in the same plane. The base slots themselves were very roughly cast, and weren't machined. When I tried to mill them true, it turned out they were chilled iron, and I chewed  up a good end mill. Even a carbide mill wasn't up to the job. That's when I shelved the project. Here are some photos of what it looked like then, and some of the problems:

[vtsteam]

I did try milling the slots again today with a homemade insert mill, but got the same result -- some chilled iron too hard for carbide. That was the last resort before trying to anneal the whole works. I was a little concerned that a casting this large might crack if reheated and cooled again in the ashes of my wood stove. I'd done that trick before with small pieces, but nothing this big.

I decided to try my oil furnace instead. Since it's insulated with refractory blanket, I figured the cool-down period might be slow enough if I covered the openings after the heat. In order to slow the heat up period, of reduce the risk of cracking, I decided to remove my oil burner and substitute my atmospheric propane burner -- originally intended as a brazing torch. It could do a slower heat up, and without all the noise of a blower ....I figured it would be up to the job.

[vtsteam]

So I loaded the steady rest castings into the furnace, cranked up the propane pressure to 12 PSI, lit the torch and placed it in the tuyere. Pretty simple. I left it there cooking while I did some nearby cleaning and inspection of a new 4-jaw chuck (not a happy experience, btw). A half hour later the inside of the furnace and the pieces were glowing orange, so I shut down the burner.

The casting is not much more than 3/8" thick in any particular place, so this seemed enough time to heat soak. I placed a fire brick over the exhaust hole, pulled the burner out and plugged the tuyere, too.

Four hours later I felt the outside of the furnace and it was just slightly warm. Same for the lid. So I opened her up, and judged the temperature to be about 200F -- low enough to remove the castings. They looked good -- all the paint was burned off, except for some powdery residue. The metal looked good, and best of all, I could notch with a flie the thin edges of the finger slots on the casting. This meant it was machinable, finally. Quite happy with the result!

[Kjelle]

Glad to hear it worked!

Kjelle

[vtsteam]

Thanks Kjelle!  The furnace is becoming quite a handy tool for a lot of things.

Today I mounted the steady on my mill, did a lot of measuring and figuring where to cut to correct the problems and then just skimmed the slots to clean them up. It was the first machining they'd had since cast. I tested the fit with 3 pieces of 1/2" x 1" hot rolled steel -- it was a close sliding fit and the fingers came together nicely and in the same plane.

[vtsteam]

I found an old casting number on my steady rest, the number 16. I was kind of curious about what kind of lathe it was made for. So I did an image search and here's the closest match:

Four hundred and fifty bucks.....     The ad also says "Quality Steady Rest" but doesn't actually mention what particular quality.......

[Kjelle]

Yours didn't look like it was even roughly machined, just a raw casting... Could it have been sold as that, not to you, but some previous owner?

I sure would have given up on it, if I had bought it for my lathe, even as "half finished", as I might not have thought of anealing it...

Good job so far!

Kjelle

[vtsteam]

Thanks Kjelle! 

I think it was sold originally as functional, not raw castings for machining. I also think it's quite old, judging by the style of the numerals in the "16". I just don't think it was made with much care -- as a guess, probably just a cheap included item in a lathe package, not probably sold as a standalone product.

It actually was somewhat "machined" -- on a belt sander for the fingers, and the bolt holes were drilled and tapped. But like the rest, that was not done very well. The topmost finger retaining hole is too high compared to the locations of the others, restricting how far that finger can move inwards.

Here are the new fingers, now slotted and the ends beveled on the mill.

[vtsteam]

Brazing the tips of the fingers:

[vtsteam]

Here's the steady rest painted and put back together. And as usual, one screw has gone missing. Well if I'm working on something complicated like rebuilding an engine, I usually wind up with one screw extra. I don't really understand the physics of that. 

I do like those square headed adjustment screws -- they look cool. I hope I find the missing one. But for practical reasons, I probably ought to replace them with straighter (and easier to turn) new bolts, or even wiser, with knurled headed knobs, because they really should be adjustable by hand, I think.

I would if I had a knurler, always meant to make one -- I even have the dies on-hand. But just one of those many projects for a future date.

Anyway, this one is ready to check off the list.

[vtsteam]

 

Doesn't fit the new lathe because the edges of the casting interfere with the carriage arms by 1/4" each side. I can't trim the casting edges, because there isn't enough meat in the bottom, and a relief would also cut into the edge flanges of the steady rest.

Uhhhh, the operation was a success..........but the patient died. 

Well, it will fit the Craftsman lathe with a riser block, with those reliefs cut into it -- the two lathes share the same ways dimensions, but I don't use that lathe much since building the new one. And I really want a steady rest for the new one.

Next steps......I thought about using the lower casting as a pattern and casting a new one, with the weak area built up. But looking carefully at the present design, it would be a pretty tricky part to cast -- the parting line would have to meander  -- looks like they might have used a two part pattern and/or coped down. And lifting a heavy  thin and deep webbed iron pattern looks like it might be tricky leaving all kinds of trouble behind in the mold sand.

A new design would be easier. Home casting, unlike commercial molding practice, doesn't require using thin webs to save on material costs, so a steady rest can be simpler in design. I think I'll just make a steady from scratch, and while I'm at it, open up the capacity from the present 2-3/4" to 4" so I can clean up the bore of larger cylinders.

Supporting large diameter stock is my present need in a steady rest, rather than turning long thin stuff. Funny thing is, the Gingery aluminum steady I built for the 7x12 Gingery lathe had 3" capacity -- larger than this old rehabilitated iron steady that was apparently intended for use in a 16" lathe.

I'll look at what I need for a pattern on the new lathe today.

This time also ........uhhhhh,.....checking for fit between the carriage arms. 

[PekkaNF]

"Here's the steady rest painted and put back together. And as usual, one screw has gone missing."

That looks what British would call a proper job!

I like squares too on lathe, no way of getting an internal hex full of swarf. Oddly I like knurled ones that has flat for spanner or internal hex. Those bolts are DIY, I am sure there are some odd commercial ones but never on self when you need some. Faster to make some from bar stock.

I bought a cheap push knurling tool...it was pretty bad. Then I bough indian made scissor knurler. It actually sort of worked, but was loose in every directions and knurl rolls were bad. Then I made some brass knobs for friends and modified that knurler to death...even made similar but with tighter tolerances. Still not happy with that.

Thinking of making something like this:
https://bbs.homeshopmachinist.net/forum/general/54725-hemingway-sensitive-knurler

[vtsteam]

Nice Knurler!

[awemawson]

If you use the original as a pattern you'll get one smaller by the shrinkage! How many times do you have to repeat this to get your 1/4" clearance 

[awemawson]

Not as aesthetically pleasing as a casting, but a perfectly functional steady rest can be flame or plasma cut  from some steel plate with a foot welded to it for the lathe bed. Many examples on the interweb particularly where people have needed large steadies.

[WeldingRod]

Stacked and welded plasma cut plates was how I did my follow rest.  Worked really well!

Sent from my SM-G715A using Tapatalk

[vtsteam]

I happen to love pattern making and casting, I guess.

Here are the pattern pieces, all cut on the bandsaw, and every edge is drafted. I don't always do that, depending on how thick the pieces are and whether there are greensand cores. Rapping can get you pretty far, but this one is done right.

A tip to those interested. When adding draft to a complicated pattern via a bandsaw or jigsaw, always proceed around the piece in the same direction with a tilted table. For instance cut as much as you can clockwise, and nothing counterclockwise. Then to clean up any needful unfinished cuts, reset your table angle (or the shoe of your jigsaw) to the opposite angle, and cut the counterclockwise edges.

[vtsteam]

The pattern pieces glued together.

[mattinker]

I happen to love pattern making and casting, I guess.

I can relate to that!

Cheers, Matthew

[vtsteam]

Matt,      it's just really rewarding to imagine a shape, take intractable stuff. metal, melt it down in a fire, pour it into some pounded sand, and then have it come out of the mold looking like a new part -- and just the shape you wanted! It's also, at least for me, much quicker to do for something odd shaped than any other method -- and less costly, into the bargain. It's just a gas!   

Okay so here's the greensand mold. Notice how clean those corners are and all of the greensand cores look precise. That's a result of drafting a pattern -- they release so much more cleanly. And a result of molding in proper moisture content ordinary traditional greensand.

What is ordinary greensand for me? Just fine silica sand, mixed with fireclay 1:3 by weight. Not even Bentonite --  though that is good stuff. But it doesn't guarantee anything. Just because you use bentonite, doesn't mean your castings will come out the way you want them. High class ingredients are just helpful, not determining.

Nope, this is just the same old 100 pounds of plain sand and fireclay that I have been using for 20 years. I use it for aluminum, zinc, and brass. Iron sand is different, but this mold will be used for aluminum.

[vtsteam]

The pour. This was from a mix of my not so good aluminum scrap -- pieces of an old auto bell housing, a thrift store trivet, old sprues, a spill from a prior session a few years ago, and other odds and ends. I melted an excess in order not only to have enough for this thick casting, but to pour some ingots as well

A steady rest is something that doesn't get used often. A cast iron version must have paint not to rust in the high humidity of my small shop. There's water on the concrete floor for one month a year in spring. It's just drying out now as a matter of fact. Even painted, anything ferrous unused for awhile will manage to rust.

This cast aluminum steady is of substantial proportions, and I think aluminum is the best choice here -- it always stays bright in my shop. Zinc alloy also stays good looking in my experience, in this shop. But I'm running low on that, and I want to reserve it for more important uses. I might cast the fingers for the steady rest in zinc alloy -- it's a good bearing material, and much stronger than cast iron or aluminum.

And no, I do not have galvanic problems in my shop when mixing any of these metals in a finished tool. That's through actual experience in over a decade with them. Likewise almost any high class machining project online mixes brass and steel in places, and they are a bad couple in the galvanic series. Okay enough of that..... out of the world of online armchair theory and back to practical experience.....and reality.....here's the pour:

[awemawson]

Well it looks to have flowed and filled nicely Steve 

[vtsteam]

Thanks Andrew! 

I forgot how easy aluminum is -- it cools in a couple hours instead of 8 or more for iron. Not so much worry about things like chill hardness or thick pasty slag, or inclusions. Aluminum dross is very easy to scoop off and tiny by comparison. Using the atmospheric burner is pleasant and quiet compared to the jet blast of the oil burner.

So I was able to unmold this pour this afternoon, and the result is a good one -- no surprises. Very slight smooth shrink cavity on the back which is hardly noticeable. the front, sides and hinge details are perfect -- which is why I placed the face in the drag. I did put a riser in  the base area, because I didn't want a shrink cavity there, and that worked out. This casting should machine out nicely, I think.

I might have to use the 12" swing Craftsman to face it as there's no easy way to clamp it down flat on the mill for that operation, and the new lathe doesn't quite have the swing to clear the hinge and base areas. But it will be easy to mount it on the Craftsman with the outside jaws bearing against the center hole.

[vtsteam]

Faced off and bored.

[tom osselton]

Nice looking casting!