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Montegoman:
I'm not sure if this is the correct place to put this info here or not.

How I restored my Edgewick lathe bed ways.

I had been nursing my old Mk2 Edgewick lathe for quite a few years, however it suddenly gave up, when I was trying to bore out a large aluminium casting, running the lathe in reverse.

It was so bad that I had to decide to scrap the lathe or try to repair it. The Edgewick lathe is a solid cast lathe; therefore it has cast in ways not replaceable hardened bed that can be bolted on.
I looked at the costs of replacing the lathe with something more modern, there was the crane-age cost to remove my lathe, plus the same costs again in getting a better lathe into the garage. Then there was the cost of a better lathe. This all added up to thousands of pounds.

What was there to lose, in trying to restore this gap bed Edgewick lathe which I had for about 40 years?

This is how I went about it.

I took out as much slack as possible on every moving part. I tightened up the saddle and cross slide as much as possible.

First I had to find out what the problem(s), were. It was quite obvious the far bed flat way was worn down but by how much? The top of the inverted "V" had no wear on it.
So I found a new sealed roller bearing that would roll along the top of the V. I bolted this to the front edge of the saddle via a strong piece of angle. I did this at the tailstock end of the lathe and checked the bearing was sitting tight on the V with feeler gauges.
This measurement was 0mm

I moved the saddle as far up to the chuck as possible, this allowed me to measure between the underneath of the saddle and the top of the flat way, and it measured 0.4 mm.
Ok, so I had to build up the flat way from 0mm to 0.4mm.




What with and how was the question. This turned to be stage one.

As an experiment I tried building up the weld on the gap bed part of the lathe, it soon became clear that the casting material of the bed affected the hardness of the weld. I ended up using a diamond disc on a Dremel just to grind the weld down, it took ages.
This now pointed to the only way to restore the lathe ways.

The obvious solution was to lay some weld onto the way, this I did. I used a 4mm stainless steel type welding rod, 309L-16.
This is an alloyed carbon electrode, designed for dissimilar metals. Welding between stainless and mild or low alloy steel. I used 2 rods crossing the way, down the full length.  Why this welding rod, the answer to that is, I had these rods already in stock.

I went back to front with the weld, (not down the length) leaving a gap between the welds, approximately 1/2" (13mm) between centres. That equates to 24 different welds about 1-1/4" (32mm) long.
With the embedded oil in the ways, the welding was not pretty but that does not matter. The hardest part of the welding was, getting the rod to start and trying not to lay too much weld on the ways, i.e. the more that is laid down the longer it is going to take to grind the weld down to the correct size.

The next problem was finding a small electric motor that was suitable to attach to the carriage. I found that a chainsaw sharpener motor was about right; it also had a flat grinding disc already attached to it. Setting this up took a bit of thinking about and quite sometime, especially getting the motor to move downwards towards the lathe bed, in very small measurements.
I purchased a 60 grit x100 diameter diamond disc to fit onto the motor.  I set the disc up level and square using feeler gauges.

Not really knowing if this method of flatten out the lathe bed was going to work or I not, I took the plunge and laid down the first 6 welds covering  6" (150mm) along the lathe from the tailstock end. This turned out to be a bit pointless as the way did not need any thickness added to this end of the lathe. However having laid down the weld, I had no choice but to grind it off but the weld was rather higher than I had set the diamond disc. It took ages to reduce the weld down low enough so that the carriage cleared the weld and would actually move forward with the motor attached. In the end there was no weld left at the tailstock end, however you can see the weld had penetrated the lathe bed.

I found that I had to move the carriage back and forth to allow the motor to cool down and allow the disc to flatten out after it had flexed over the larger lumps of weld. I saved quite a bit of time by using a grinderette on the higher welds in front of the carriage before the diamond grinding disc came along to bring the weld down to the correct height.
The weld closer to the chuck was showing signs of it working, it had gained a few thou, or what ever that is in metric. I moved onto the next section to be welded and repeated the process, until I got to the gap bed and when the motor touched the chuck it was time to stop.


I then had to take a chance and take the motor off the carriage and then run it right along the bed to see how it reacted, it went along very smoothly.

Now to see what happened when the lathe was put into reverse, this turned out to be stage two.
The carriage rocked backwards which was not good but it was flat and not climbing out of the dip in the far side flat way anymore.
The front inverted "V" way had also warn away on the inside face, so when the forces pushed the carriage backward into the damaged face, the tool cut into the material.

Ok; how to temporary fix this problem? Having used the roller bearing on the carriage vertically, could it be used to stop the side movement on the carriage, horizontally? The answer is yes. Again I attached this bearing, which was attached to a piece of angle iron to the front end of the carriage.
This will only work If your lathe bed has a flat straight solid edge in the middle of the lathe running along the full length of the lathe.
If you are lucky to have this setup, this vertical surface needs to be cleaned off, so it is smooth and flat, i.e. no lumps or bumps or hollows, as this method is only has a "point" loading location, not the full sliding surfaces of the carriage.

I set the carriage as far back as possible to take out All of the slack in the movement of the carriage, I then fixed the bearing up, good and solid, hard against the vertical face of the inner lathe bed. This worked, now the carriage has very little slack movement, when in reverse and the cut is the best I have had for years.

As already mentioned this is only a temporary fix, the lathe bed front inverted "V" will now need welding and regrinding just like the rear one but now the carriage is useable and quite accurate. Fixing the front way should improve the accuracy of the carriage even more.

I hope the above information is of use to someone else who has the same problem as I had with my lathe.

All the best
Montegoman.

awemawson:
Full marks for lateral thinking, but conventionally you'd scrape the bed down the 0.4 mm and adjust the lay of the carriage to suit having scraped its base to a good fit.

I'd be rather concerned that the welding would distort the casting.

russ57:
Can turcite (?) be used to fill wear like that? Seem to remember something like that, but not sure it is a diy proposition. Sounds like physical removal is not trivial.

Regards
Russ

-russ

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