Thread: Myford Bed Regrinding

Originally Posted by DSEL74

I think it will take more than a little bit of hand scraping to get it back to flat.

Maybe a grinder first, then scrapping, if it's that bad.. How about offering it as a demo piece for the next 10 scrapping sessions.
Kryn

Originally Posted by DSEL74

I was wondering if anyone has an idea what it would cost to have a little Myford ML7 bed and saddle reground? The head stock would need to be split so that can be ground with the bed to keep the centre height aligned. I don't know if turciting the saddle is an alternative to that.

Basically if I adjust the gibs so the lathe is nicely set at the headstock I can only move the saddle 5-6" down the bed before it binds. Or if I have it so I can run the full length of the bed it is sloppy as hell down near the head.

As always funds are tight so I'm trying to work out if I'm chasing my tail trying to get this old thing in a reasonably usable state or I should bin it and look for something else?

I guess Phil is probably the one who knows but I'm interested in others experience in this kind thing also. I think it will take more than a little bit of hand scraping to get it back to flat.

Only my personal opinion, but I would look to getting the bed reground. The bedways and shears are dead flat and I suspect that there won't be a lot of work to get them right. Plus the Myfords are a much sought after lathe and bring very good money even in a worn condition.

However do check that things are clean under the saddle because bits do migrate under there and can cause tightening as you move away from the chuck. It always surprises me just how much stuff gets embedded in the felt wiper at the front. I take mine off every now and then, wash it in white spirits, then soak it in oil before putting it back. Just doing this changes the feel of the saddle movement.

If I had to guess I would say around a thousand dollars just to grind the bed...

As an out there idea, have a word with the Myford guy in the UK... I suspect you may be able to drop on a NOS bed for cheaper than getting yours ground locally. I find this whole replace with new being cheaper than repair concept wrong but I guess its the world we live in now-a-days.

Kryn, Is there going to be another scraping class????

BaronJ, I try taking the saddle off and doing a clean as per your method. I just got a new cross slide screw as the original one was bent.

RC $1K is not going to happen I don't have that kind coin.

ventureoverland, I think that the cost plus shipping would be prohibitive.





It is a fairly simple design with no Vee Ways

Originally Posted by DSEL74

RC $1K is not going to happen I don't have that kind coin.

I think that's a *very* realistic estimate of a minimum price, frankly.

If you can't afford it - or don't think your lathe is worth that much money - you're left with the alternative of hand scraping it yourself.

Assuming you have or can obtain the tools required that is, because buying them new is probably going to cost over $1000. I'm about to get some more straight edge castings done and I expect that a 650mm casting is going to be close to $200, which then needs to be machined and scraped, which means a surface plate, which costs....

PDW

Originally Posted by PDW

I think that's a *very* realistic estimate of a minimum price, frankly.

If you can't afford it - or don't think your lathe is worth that much money - you're left with the alternative of hand scraping it yourself.

Assuming you have or can obtain the tools required that is, because buying them new is probably going to cost over $1000. I'm about to get some more straight edge castings done and I expect that a 650mm casting is going to be close to $200, which then needs to be machined and scraped, which means a surface plate, which costs....

PDW

It's not a matter what the job is worth rather what I can or can't pay. Which is why I am questioning what it will cost and if I can achieve it or should quit on it now.

It might be a "hand job", I do have a straight edge but it is fairly narrow about 15mm wide came from boeing, the parallel kind not camel back, I also have some small surface plates with the side handles that may be able to be used for blueing, and a scraper from Phil's course. I think that my ability is more in question here.

How long is a Myford ML7?

Stuart

Originally Posted by DSEL74

It might be a "hand job", I do have a straight edge but it is fairly narrow about 15mm wide came from boeing, the parallel kind not camel back, I also have some small surface plates with the side handles that may be able to be used for blueing, and a scraper from Phil's course. I think that my ability is more in question here.

Yeah, well, that's what practice is for.....

Question I always ask myself when things like this come up is, can I make it any worse than it is now? If so, how? Then avoid doing that.

Myfords have easy to scrape flat sections. Work out a plan for mapping the wear then consider how to go about dealing with it. Keep in mind that your alternative is to live with it and any improvement is a plus - IOW don't have to aim for perfection, just sufficient improvement to make the machine more useable.

I assume you have a copy of Connelly's book and Schlesinger's as well. They're both available as PDF copies for download.

PDW

Originally Posted by DSEL74

It's not a matter what the job is worth rather what I can or can't pay. Which is why I am questioning what it will cost and if I can achieve it or should quit on it now.

The only way you will find out the cost is ring around...

Also consider since it is small and just soft cast iron, it could be milled flat, or planed... it is also all going to count on if the operator doing the job knows what he is doing, as I could well imagine those sort of people are becoming less and less in Australia...

I am sure given the huge popularity of Myford's there would be a large amount of knowledge out there mostly in the UK on rebuilding such a lathe for a reasonable price..

What you describe is a common issue with Myford lathes but it is also one that you can fix yourself as long as the wear isn't too excessive.
The first thing you need to do is establish the location and extent of the wear which being a flat bed lathe is a relatively simple task.
Of course there will be wear in the saddle but as it only binds as you move away from the head stock this indicates that the major source of the problem is in the bed itself so don't worry about the saddle for now.

There are basically five bed measurements that will allow you to establish an approximate wear pattern (refer to attached drawing):

Attachment 346152

1 - Rear shear thickness.
2 - Rear shear width.
3 - Front shear thickness.
4 - Front shear width.
5 - Bed width.

First step is to establish a rough benchmark of what the bed looked like when new, this can be done by taking a set of measurements a couple of inches in from the tail stock end of the bed where there should be virtually no wear.
Following this take a series of these measurements along the length of the bed about an inch apart starting from the gap under the headstock.
Record all the measurements as you go and by the time you're finished you should have an indication of where things are worn and how badly.
What you will most likely find is the shear thickness and bed width will get smaller closer to the headstock.
When you have worked out where the wear is you will need to establish which surface is actually worn down and the shape of the wear pattern, this can be done using a straight edge and feeler gauges to locate any hollows

Ideally if you have access to a surface plate and camel back type straight edge or similar you can strip the lathe down and proceed to scraping as we did with Phil and Marco, this of course would be the best possible scenario and give the best results.

If you don't have access to these though you can use a simple blade type straight edge and feeler gauge to approximately mark out the wear pattern which should still allow you to scrape things in close enough to extend your lathes capabilities. This method will not give you any sort of super lathe and before any purists get all hot under the collar I'm coming at this from the point of getting a lathe you are considering dumping back to a condition that will let you use it more completely than you can now, all without expensive grinding, tooling or even disassembling the lathe.

The only thing you have to loose is some of your time (probably a lot actually) but by the time you're done you will have learnt a hell of a lot and might even have a better lathe. I should add here that I went through this process with my little ML7 which had the same problem. I did this after doing Phil's training in order to prove to myself that I could actually use the skills learnt for a practical purpose, and it also improved the lathe.
Cheers,
Greg.

Bed is 65cm long and bed, gap & headstock are 95cm long combined.
Front way is 45mm rear 35mm. These are approx, actual sizes would be imperial also.

Yes I'll need to try and measure the wear and the pattern.

That should fit on my plate if I ever get to see it again(the plate that is)

Stuart

That's the problem with surface plates, you rest something on them and then they breed rapidly, till you can't find it . I have the same problem with any flat surface.
Kryn