Steady Rest For Colchester Master (and Standard Modern 1340)

[RobinHood]

As many others have done as well, I needed a “COVID 19” project.

My Colchester Master 2500 did not come with a steady rest. They are available online. Prices are very high - at least the ones I have seen.

This is what an original one looks like

Not sure of its capacity - looks like about 4” or so. I’ve had occasions where that would not have been large enough.

So I decided to make my own. Could I possibly make one that would work on the SM1340 as well? The one it has is only good for 3.125”. If it was going to be universal, the base had to be removable as the geometry of the lathe beds is different. So the original plan was to have one base for the Colchester and one for the SM. Also, it should be able to handle up to ~ 8” stock. Oh, and one more little challenge: nothing will be bought - everything can be made in the shop, if needed.

So here we go. I decided on a hex shaped top section. Incircle radius of a hex = square root of 3 / 2 x the length of the side. From that I knew my inside hex sector lengths needed to be about 4.6”. I made a wood model.

Found heavy wall square tubing in stock and cut six pieces. Here they are ready for welding, welded, and ground.
(good thing I am better at grinding than I am at welding...)

Next it was off to the mill to true up all sides. This is how the angles were set with at least some degree of accuracy.

The 1” holes for the base connector pins were milled next.

Then the holes for the push rod tubes. No real good way the hold the part in the vise - way too tall. So I used an angle plate and hung the part off the back of the table and swung the head around to reach the position. Front and back views.

Next I worked on the rear hinge mechanism. Basically it is three rings axially - outside two welded to the bottom half of the hex and the center one to the top with a pin through them. I left the front of the steady rest welded for now to keep the alignment.

Then I cut the front to make the closure mechanism. Again, the part is held with an angle plate off the back of the table. Some more not so good welds (porous).

Here we are working on the push rod tubes which will be welded into the frame later. Material is heavy wall DOM for the tube, drill rod for the 7/8” plunger. 1018 mild steel for the spindle, retainer collar and the knob.

Time for the base. Lob off a chunk of mystery metal off the billet. Mill all sides. Don’t like the finish. Use the surface grinder to make it much better.

 

[RobinHood]

The Colchester has 80* Vs (yeah, why not); the SM uses 90*- seems more like the norm. That is a challenge. Don’t have an 80* cutter. Can’t use an end mill with the part set to 45* -> that will give you a 90* V. Maybe a fly cutter -> that is a deep V (flanks of the V are ~ 0.500”) and would be hard on the mill. I have a 45* cutter. So I set-up the part 5* off of horizontal to give me the 40* flank angle for the 80* V. But first a cut down the middle of the V with a slitting saw.

Then a big problem: the cutter is not very tall so no way to hold the part on the tilt table. The strap clamps were too high and the arbor would hit them.

Since the base needed holes for both the frame and the hold down shoe anyway, I drilled them. Unfortunately I could not divide 3.012” by two in my head properly (I got 1.006” - yeah only 500 thou out) so that the first set of holes were 1/2” off of my reference line. Time to walk away!

The circled ones are in the wrong spot. Turns out there was enough material that I could flip the part 180* and did not have to scrap it.

Now that we had holes, I could use SHCS in the part to hold it to the tilt table. Hurray!

The joy only lastEd until I was trying to cut the other 40* flank. The part is too long and even a little 5* tilt does not give clearance on the up side. Time to walk away again!
I do have a 60* full V cutter. Aha, if you tilt the part 10* into the cutter the 30* cutter flank will cut the 40* that is required. What’s more, the part will be tilted away from the arbor and we have clearance! Unfortunately I don’t have a picture of that set-up.

The good thing of my math screw-up gave me time to rethink the two base plan: I then realized that with the hole location I just had to mill a 90* V for the SM lathe on the opposite side and be done with it. That’s what I did next, using the 45* cutter again with the part horizontal.

Next we made some locking screws (the knurled knobs are surface ground) and brass pads

Close - up of a push rod, anti-rotation slot and locking screw.

Some 1/2” hot rolled serves as clamp shoe (they are different for each lathe, so no universality here). Finished product: on the Colchester and the SM. The original steady is in front of the new one on the SM1340 for size comparison.

Sorry for all the sideways pictures - no idea what is wrong.

EDIT: went back and re-uploaded the pictures, They should now all be in the correct orientation and easier to view.

 

[YYCHM]

Interesting that you posted this the same day I finally had a need to use my steady rest.

I love the flip open arrangement. Had to take my sample out 3-4 times for a test fit. Just plunk her back in and away you go.

 

[PeterT]

Good job, Rudy. Especially with the constraints of using materials & tools on hand. There is a lot more than meets the eye on those steady rest assemblies.

It's too bad there aren't reasonably priced casting shops around like back in the day. So many typical machinery parts we take for granted probably started out as wooden patterns.

 

[DavidR8]

That's some nice work there!

 

[YotaBota]

Well done, now you can fix that driveshaft for your monster truck

 

[RobinHood]

Yup, should be big enough for that.

 

[Dabbler]

First rate!

 

[YotaBota]

Some more not so good welds (porous).

Are you using stick or MIG? Any idea what's causing it?

 

[RobinHood]

Stick / TIG - I don’t have mig.

maybe the base metal was too cold, or
the electrodes too old (I got them about 6 years ago), or
the electrodes damp (no rod oven), or
the cutting oil used on the bandsaw that was still inside the tubing boiled off during welding (even though i tried to clean as much out as I could), or
dissimilar metals (some 1018 and mystery metal), or
wrong argon flow, or
operator error (not enough experience), or
....

seriously, there are a lot of factors that I probably did not have under control sufficiently to make a good, consistent weld. The joints are strong and probably will never break, so I should be happy I gues.

Funny thing is on the farm we just welded stuff without much care for prep (other than the basic bevels) with the old Lincoln buzz box. The metal would be frozen, dirty, covered in paint, oily, and the electrodes were damp and yet we got what appeared good looking welds. The welds themselves never broke anyway.

Now I have a fancy Everlast with all the latest electronic controls and I get porous welds. Go figure.

 

[YotaBota]

I think you've covered most of the maybe stuff, the only other thing I can think of would be to long and arc. I was getting the same porosity thing with some 10 year old 7014, threw it in the old toaster oven at 250 for a half hour to cook out the moisture and it worked well after that. I've been meaning to buy an airtight rod can but haven't got that far yet.

 

[RobinHood]

the only other thing I can think of would be to long and arc.

that is a very good point. Will have to pay attention to that as well.

another interesting note: I have an old Miller Bobcat 250 welder/generator; the weld quality seems better on it (like on the old Buzz Box) than on the Everlast. I wonder if today’s electronic IGBT welders produce “too clean” power compared to the old transformer rectifier machines? Seem more finicky.

 

[Dabbler]

electronic IGBT welders produce “too clean”

I think it has to do with marginal design - nowadays all consumer goods are produced to a price. In many cases that means designing it to what is expected for some percentage of expected use. Up to recently, industrial machines were developed for long service life in all expected functions.

I'm not surprised that you found a limitation in your machine. I like Everlast and they make good product - you may find similar limitations in most consumer or prosumer welders.

 

[YotaBota]

I have an old Miller Econo Twin HF that has a winder for amps, no display or push buttons and it works flawless. I haven't used TIG in a long time but it's probably time I bought a gas bottle and see if I can still do it. I like the older, simpler stuff (ya like me) because it usually works well and can be serviced easier, the only reason I traded in my flip phone for a "smart" phone was for connection to the car and the phone was on sale.

 

[Dabbler]

@YotaBota we may have the same welder!

 

[RobinHood]

I'm not surprised that you found a limitation in your machine.

Can’t be 100% that I found a limitation in the Everlast because it could well be operator error.

I have never had formal welding training. It was basically watch how the neighbour farmer welded in his shop (he had formal training), make some notes, give it a try with his machine, go buy our own, and have at it. Cover it in paint. If the weld did not break - job done.

 

[RobinHood]

Pictures are now fixed. Uploaded them again after pretending to “mark each one up” offline. The upload kept the orientation as I have them in the photo library - no more funky rotating.

 

[Chicken lights]

Can’t be 100% that I found a limitation in the Everlast because it could well be operator error.

I have never had formal welding training. It was basically watch how the neighbour farmer welded in his shop (he had formal training), make some notes, give it a try with his machine, go buy our own, and have at it. Cover it in paint. If the weld did not break - job done.

You know how many “temporary” fixes end up being permanent fixes on the average farm? Probably 90% of them, if I had to guess

 

[RobinHood]

Agreed. That’s why we tried to do it right the first time - at least for the majority of times.

 

[YotaBota]

RH - what is the reason for using the connector pins vice welding the base to the frame.

@YotaBota we may have the same welder!

Here's my old faithful.