Thread: Slop on tailstock

I thought I'd read about a fix for this - here it is https://www.woodworkforums.com/showth...ck+mc900+plate

Thanks, Keith. I could vaguely remember there was a post about this and it struck me how long it took Shorty to fix it. I may well have to go down that track but before I do that, was going to investigate other options.

You could try the following.

First check that the bed gap and bedways are a constant width and thickness. If either of these are out you have a major problem.

Turn the tailstock upsidedown and using a centrepunch and hammer it may be possible to swell the cast iron and make the centres line up. Lots of checking as you go is required. Take care not to wack the cast too hard because you may crack a bit off. Lots of gentle hits are the go.

Most people are happy if their centre points meet. However this is only part of the solution.

For true accuracy when drilling with the tailstock and making small finials or minitures between centres, the headstock and tailstock spindles need to be in perfect aligment with the bed.

Vicmarc machine their headstock and tailstock in a jig, together as a pair.

When their bed is machined on their VL300 series lathes, it is machined from end to end and the headstock then slots into the bed.

A good check on the quality of the lathe is to see if the headstock is keyed into the bed, or is it just bolted onto the bed.

You gets what you pay for.

Hope this helps.

Cheers

Tim

Thanks, Tim. I might try the centrepunch but it is cast iron, just not sure how much of a whack it can take.

G'day Tiger

I don't think there is much you can do to the tailstock that will remedy this problem until you get the ways parallel and consistent in spacing. I can only assume that most of the MC1100 and MC900 lathe beds come out of the mould in a similar condition. One thing I have found is that bringing the tailstock and headstock together only confirms the alignment at that particular point in the bed. I confirmed this by putting a jacobs chuck in each end and inserting a 450mm steel rod in each chuck. This meant that the head an tail were now approximately 900mm apart and the two still did not line up correctly even after all the work I had done on the bed and tailstock. It was close but not close enough for my liking. (depends on how fussy you are i suppose) It then occurred to me that the headstock was also out of alignment so I removed that as well and filed one side of the locking mechanism until it was as close to perfect as I will ever get from a $500 lathe. It sounds like a lot of hard work and trust me, it was. Especially hand filing the ways. But now that it is done the lathe is so much better to use.

Cheers
Shorty

For simple tailstock support, the axis of the tail-spur doesn't need to be aligned with the headstock spindle axis, just the effective tip.

However, it should be aligned as well as possible if you want to use the tailstock for other purposes, such as accurate drilling, long-hole boring, etc., especially with the tailstock up close 'n personal to the headstock. (The further away, the less any alignment errors matter.)

Accomplishing this on an MC-900 casting is... a PITA. However, it can be much improved over what it is with just a little effort

The fact that the gap between the ways is all over the place doesn't really help, either. On both of mine I simply filed back the rebates on each side of the tailstock casting, so that they were parallel to each other and the MT axis. Then I epoxied brass shims in place, to bring 'em back to the width of the narrowest gap in the ways.

Sometimes I wish that, like TheFixer, I'd filed that narrow section a little wider - I guess I still can - but I'm inherently lazy and I can live with the tailstock being a bit "sticky" as I move it through there.

It's not perfect, not by a long shot... but it's accurate enough now that the error caused by swinging the headstock into outboard mode and back again is a bigger problem. And I can live with that too.

After all, it doesn't effect the quality of my turnings... although not having to deal with it would make my lathes a bit easier to use. Not that much easier though, not enough to make it worth my while bothering trying to fix. Purely IMHO, of course.

G'day Shorty, I read your other post where you meticulously filed away the bed to get an even spacing for the tailstock to ride in. My bed has small inconsistencies but how do you know which rail of the bed to file or do you take a bit off each rail? In other words how do you guarantee the bed is parallel to itself and to the headstock.

By the way, your solution to alignment of the headstock and tailstock was brilliantly thought out. Do you have a solution to the clamping mechanism which clamps the headstock onto the bed. The existing mechanism does not provide enough purchase but I have not seen a solution that I am totally satisfied with.

Originally Posted by Tiger

Had this problem for a while and I tried to remedy it with some body filler but it just fell off. My tailstock has a couple of mm of slop which makes lining up the centres difficult unless I remember which way to rock it and then tighten the lever. Would really like to have it so that the slop is minimal, what solutions are there?

Tiger

Instead of Body filler try Kneadit { found at bunnies, Mitre10 etc for about $20 } it's a 2 pack metal putty that will stick to anything once its gone off you can sand and file it to rebuild your bed about the only thing you cant do is wld it , you'll need to get devcon { onother 2 pack metal } or something like that

Hope that helps and good luck

Thanks, Glenn that sounds like a good fix and if you get it wrong, it's not too hard to start again.

Beer cans to the rescue.... ever consider using a shim? I often use a sliver of a beer can as a shim to make adjustments where mating surfaces have become worn.

Just a thought....

but ... the misalignment is not a great problem IF you don't take the piece off and back on. As you are tuning between the point A and point B whereever it lies. I have a notch filed in the Spur center and always align the notch with a mark on the work when I remove and replace the work, (the tailstock will remain the same and thus the turning will be "between centers" Align "not at the notch" will be the same effect as "offset turning" to a small degree. Now, If you are drilling or otherwise using the tailstock or other applications, this may be a slight problem, but as the SKEW has said, it is nothing you can't deal with.

Another solution is set screws... Drill and tap the inside rails of the tailstock, insert set screws and adjust the spacing along the Ways...

Originally Posted by Tiger

G'day Shorty, I read your other post where you meticulously filed away the bed to get an even spacing for the tailstock to ride in. My bed has small inconsistencies but how do you know which rail of the bed to file or do you take a bit off each rail? In other words how do you guarantee the bed is parallel to itself and to the headstock.

By the way, your solution to alignment of the headstock and tailstock was brilliantly thought out. Do you have a solution to the clamping mechanism which clamps the headstock onto the bed. The existing mechanism does not provide enough purchase but I have not seen a solution that I am totally satisfied with.

G'day Tiger

If you notice in my thread about filing the ways, I used a length of steel about 150 mm long that I had filed perfectly parallel to the same size as the widest gap in the bed and I just kept placing that in the ways and sliding it along until it got stuck. I could then see a mark where it touched and then filed that bit away using the file lengthwise along the bed. I kept doing that a bit at a time and eventually achieved my goal.

Getting enough purchase with the existing clamping mech was not an issue. Stopping that bloody nut from loosening itself all the time is the problem. See my fix for this in reply to your thread "MC900 mods" https://www.woodworkforums.com/f8/mc900-modifications-102036 Once you lock that nut at the right position and get the right amount of travel on the lever the cam lock works exceptionally well

Cheers
Shorty

Thanks Hickory and Shorty.

Hickory, I thought about the shims but there's a mm or 2 to shim which is probably too much to shim. I like the set screw idea but would it score the bed rails as it slides along the bed?

Shorty, thank you for clarifying your method. I like it and will probably do it next time I have a few hours to kill. The other headstock lifting when turning between centres has been a problem that is difficult to fix. I posted something under headstock flex in this forum and the miscast claw that is supposed to lock the headstock down is the problem.

The set screws really don't seem to mar the ways. But which is you greatest concern, the alignment or the surface finish of the machine? As the machine ages it will accumulate a number of battle scars. These are just part of the sacrifices for being worn out.

Many of the school shop machines were adjusted by set screws and not a noticable problem.

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but ... the misalignment is not a great problem IF you don't take the piece off and back on. As you are tuning between the point A and point B where ever it lies.

I agree, sometimes I think we look at misalignment as a major problem in a wood lathe, in certain circumstances it is. But for the rest it does not matter too much.

Fortunately most of my turning does not require such accuracy, only wobble is a problem and for the most part its not too hard to sort out. I managed to get my MC1100 to swing a 15kg lump with out any appreciable wobble from sloppy machining. But the legs darn near gave way and so I built a new solid base and all was well again.