Headstock Alignment Factory Provisions.

[RobinHood]

On a side note, how sufficient would 4 bolts mating two flat surfaces be for a headstock? No V seating or anything else, just two surfaces stuck together with 4 bolts in slightly oversized holes holding it together.

Well, on my 10 hp, 19” swing CMT lathe there are 6 bolts, one pin to swivel about, and an adjusting block at the very left end under the HS holding things in alignment.

I would think on a lathe your size four bolts, a pin and the adjuster should be strong enough to secure the HS to the bed.

My guess is you are thinking of machining the V off the bed and just bolt the HS to it (properly aligned)?

 

[opensourcefan]

Well, on my 10 hp, 19” swing CMT lathe there are 6 bolts, one pin to swivel about, and an adjusting block at the very left end under the HS holding things in alignment.

I would think on a lathe your size four bolts, a pin and the adjuster should be strong enough to secure the HS to the bed.

My guess is you are thinking of machining the V off the bed and just bolt the HS to it (properly aligned)?

Thank you.

Yep, my thought was cutting an inch and some off the bottom of the head stock effectively creating a base with the head on top. Adding a rotational pin and an adjustment as you mentioned would also be added. If I slightly enlarge the holes on the base then I should be able to have the space to adjust. Now I haven't done any measuring or anything to see if I have the thickness to pull that plan off.

 

[140mower]

Lol, sorry if I woke you. Good morning to all. My shift working has never coincided with normal people.

I'm thinking that if you came here looking for normal people......
I never did well with shift work, I find it hard enough getting the required rest without messing with my sleep schedule.
I'm liking the idea of shimming and epoxy that way you can scrape a little bit out of the way at either end if needed for clearance. I'm glad my old South Bends haven't given me that kind of grief.

 

[gerritv]

Thank you.

Yep, my thought was cutting an inch and some off the bottom of the head stock effectively creating a base with the head on top. Adding a rotational pin and an adjustment as you mentioned would also be added. If I slightly enlarge the holes on the base then I should be able to have the space to adjust. Now I haven't done any measuring or anything to see if I have the thickness to pull that plan off.

you'll lose a lot of rigidity that way, it is unlikely there is that much meat on your casting.
The mistake made during manufacture seems to be that the V in the head stock is too close a fit to the V on the bed. If you open up the V in headstock then you get some wiggle room without redesigning the whole thing?

Unless of course you want a swiveling headstock ala Unimat DB200 and Sherline. Then I would take the V off the base and add a pivot.

Gerrit

 

[Rauce]

I would think the v is actually meant to be contact with the headstock. The problem would be that the female V in the headstock is not aligned with the spindle. Presumably the V in the bed is straight along it’s length.

 

[opensourcefan]

I would think the v is actually meant to be contact with the headstock. The problem would be that the female V in the headstock is not aligned with the spindle. Presumably the V in the bed is straight along it’s length.

Yep, that's exactly what I think the issue is. The seller stated that they never have this issue, true or not,they don't have a mechanism for adjustment really so I imagine they're relying on the V to seat and align.

Taking that into account, I'm sure many have seen my machine is very green. However when I look close I can see red in some spots, blue maybe as well if my memory serves. They're doing nothing more that grabbing pre manufactured parts and slapping together a different machine with some added fluff or tweaks.

 

[Susquatch]

Thank you.

Yep, my thought was cutting an inch and some off the bottom of the head stock effectively creating a base with the head on top. Adding a rotational pin and an adjustment as you mentioned would also be added. If I slightly enlarge the holes on the base then I should be able to have the space to adjust. Now I haven't done any measuring or anything to see if I have the thickness to pull that plan off.

I'm not on that page. In my view all machines are a compromise of competing goals. If you cut anything off your bed you will sacrifice rigidity and vibration. They are too important to give away in order to achieve an improvement in axial alignment. What good is perfect alignment if you can't cut soft butter...... (gross eggageration of course).

I suspect your bed ways are fine (or at least close enough for all intents and purposes) for the size of your lathe. And assuming there is nothing between the head and the bed that is throwing off the alignment (have you removed the head and looked yet?) then I'd wager that the bottom of the head is prolly good too. It's just too difficult to accept a major flaw like that happened. If there is nothing on the ways, my guess is that the top half of the head is misaligned from the bottom half causing the spindle to point where it shouldn't.

Whether or not that exists, and if it cannot be fixed directly, I would much prefer to shim the ways as you have already done. Just finish the job. You can then go for a full repair with full length epoxy bedding if you want. But I do like what others have said about shimming, bedding, and then finish bedding without the shims.

I doubt very much that you will ever need to do this again. Therefore not much point in trying to design in any future adjustability.

It will be a lathe to love when you are done.

 

[opensourcefan]

If you cut anything off your bed you will sacrifice rigidity and vibration.

That be crazy, I know I'm up to being crazy but I wouldn't do that. I meant cut an inch off the bottom of the headstock casting. Leaving two flat surfaces which one will receive a pin etc. I'd only lose an 1/8" but like I said not sure if it'll be possible.

Edit: oops, it's 3am again...

 

[Susquatch]

That be crazy, I know I'm up to being crazy but I wouldn't do that. I meant cut an inch off the bottom of the headstock casting. Leaving two flat surfaces which one will receive a pin etc. I'd only lose an 1/8" but like I said not sure if it'll be possible.

Edit: oops, it's 3am again...

Do you actually sleep?

I would not cut anything off the bottom of the head either. Same reason. The lathe is only as good as it's weakest link.

If universal adjustability was that important it would be built into every lathe on the market.

I think it's only on the bigger ones because it's so difficult to align them any other way and their size makes it easier to get out of alignment.

Anyway, my point is that once yours is aligned you will prolly never touch it again. Why go to so much trouble to facilitate something you won't ever use again? If it were mine, I'd just align it, and be done with it.

 

[Darren]

I would be asking for a new head casting, or looking into reboring the bearing bores. You will surely have geartrain alignment issues if the spindle is that far out of alignment. Maybe not a huge issue for a hobby lathe, but something to consider if you want it to be right.

 

[cuslog]

I would be asking for a new head casting, or looking into reboring the bearing bores. You will surely have geartrain alignment issues if the spindle is that far out of alignment. Maybe not a huge issue for a hobby lathe, but something to consider if you want it to be right.

Son worked several years for a major oil field C0., built their own drill rigs etc. They used to buy offshore pumps, blow off preventers etc. Job one was to strip them apart, re-bore all the bores and replace all bearings. Major castings / forgings were what they really bought them for, most of the bores / bearings were wonky in one way or another. Still worked out cheaper than buying North American or Euro.

 

[opensourcefan]

Anyway, my point is that once yours is aligned you will prolly never touch it again. Why go to so much trouble to facilitate something you won't ever use again? If it were mine, I'd just align it, and be done with it.

Yes, I most likely will end up at that after I exhaust all my mental dreams and plans and get to actual work

 

[PeterT]

It would be useful to see some pics of your headstock & underside V-groove as well as the lathe bed footprint it resides on. Or maybe snip of the shop manual if it shows this detail?
I cant visualize a scenario where the HS V-groove is milled straight but the spindle is bored at angle. I mean anything is possible but one would think they have reliable fixturing for this important stuff.

If its 'only' the V-groove that is the culprit, that might not be that onerous of a job. But first things first. I can think of a few things that might assist jigging to ensure alignment success. And epoxy selection is another topic.

 

[opensourcefan]

It would be useful to see some pics [snip]

The front third is over top of the gearbox. The 4 bolts go into the bed casting. I don't have any of the underside yet but the first plan is to remove, inspect,clean and inspect again, reassemble, test. If it doesn't magically fix itself then I'm gonna have fun.

I'm going to install a stepper motor onto some gears so I can remotely turn the head in any direction. Kidding, that was for @Susquatch

 

[PeterT]

So the manual infers 2 Vee slots, at least as drawn on the chuck side. But your picture shows a Vee slot on operator side & rectangular clearance slot on other side? Does that rectangle run right across the headstock? Do you have a pic of the lathe area where HS is bolted to?

 

[PeterT]

If the HS were to be remedially rotated slightly so the spindle was corrected parallel to ways, is there any metal to metal drive train connection to gears below? Or is it just a rubber belt from those up to the spindle? (ie. wondering about secondary misalignment once HS is shifted).

 

[opensourcefan]

If the HS were to be remedially rotated slightly so the spindle was corrected parallel to ways, is there any metal to metal drive train connection to gears below? Or is it just a rubber belt from those up to the spindle? (ie. wondering about secondary misalignment once HS is shifted).

Just a belt to the spindle pulley. The gear train is on it's own arm (seen hanging off to the right) which can be rotated and adjusted to suite. No worries after the fact.

 

[opensourcefan]

So the manual infers 2 Vee slots, at least as drawn on the chuck side. But your picture shows a Vee slot on operator side & rectangular clearance slot on other side?

Oh the manuals for these lathes can't be trusted. The clearance slot goes all the way, only a single V as a seat. No pic of the bed sans headstock yet.

 

[PeterT]

Is this red stuff some kind of adhesive or just primer poking through?

 

[opensourcefan]

Just the décor from the previously painted stripes on the bed channels before the manufacturer covered over them in their own green.