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By sunnybob
#1186777
Hello, I'm new here... :shock: :lol:
I've just acquired a hobbymat universal MD65 lathe.
Its somewhere around 20 years old but has not worked all that hard. Checking it over I found that the headstock bearings needed greasing. the book says 1500 hours, but as I have no idea how many hours the lathe has run, and i dont actually know exactly how old it is, i thought I would like to.

Then i found this lathe needs 2 x C spanners to remove the locking nuts. So heres where you all come in.

Where do i get the spanners from?
do I actually need them?
What direction of thread are they? No thread is visible so I cant just force them with pipe grips.
I'm not precious about the finish if pipe grips will work, just need to know which direction to push in.

Also I would be interested if any body has the angle plate that turns the slide sideways for milling if any one has one.
User avatar
By Harbo
#1186802
Can’t help with the Hobbymat, but ArcEurotrade, Chronos and RGD Tools are places I look for lathe accessories.

Rod
By AES
#1186912
I also can't help with this lathe, but try the Lathes web site (see sticky at the top of this section); and +1 for the comments re suppliers mentioned above (also all in the sticky).

No idea which way those nuts turn, but at a guess I'd say normal RH thread direction, but ONLY a guess ('cos you say there's 2 nuts - probably locking each other). That lathes web site will probably tell you.

Don't know if you can see the nuts at all, but if well enough to measure the dia with a caliper, then it's easy enough to knock up a pair of C spanners out of say, eighth inch steel plate. Proper tools (or tools from the lathe manufacturer, if available) are not likely to be cheap, and are needed seldom.

HTH (just a little bit anyway)!

AES
By sunnybob
#1186932
There doesnt appear to be a factory website for this one. I have found a couple of mentions, even one who made his own C spanners.
What amazes me is that the manufacturers dont seem to have made or offered for sale these spanners. the handbook gives step by step detailed instructions for removing the spindle, right up to "undo the locking rings". How helpful is that?

I have reasonable access to the collars, they are 32 mm diameter with a 4.5 mm pin. I'm just annoyed that I will have to spend so much time making TWO of them because 1 wont work. But even then, I dont know which way to turn them. I have already tried two pipe grips and got no movement at all.

I have some stainless steel rod that I have turned down to fit. I shall have to go beg some steel today.
By AES
#1186950
Sorry to hear all that sunnybob. I can just imagine your frustration!

The only other suggestion I can offer before you start making C spanners (sounds like they're "peg spanners" BTW) is to ask your Qs on the Model Engineer/Model Engineer Workshop web site. Again, see sticky at the top of this section.

There's bound to be at least one member on there who knows your lathe. I feel doubtful about offering any more "advice" as I just don't know your lathe - and from the looks of things, neither does anyone else on here.

Best of luck.

AES
By J-G
#1186961
sunnybob wrote:I have reasonable access to the collars, they are 32 mm diameter with a 4.5 mm pin. I'm just annoyed that I will have to spend so much time making TWO of them because 1 won't work.

I have made my own in the past but not from 3mm sheet, I turned a ring and cut that in half, adding a handle and a pin but that was for a totally non standard collet chuck I built.

Cromwell offer a range of 'Standard' C-Hook Spanners one of which would suit your 32mm Dia. :
https://www.cromwell.co.uk/shop/fastene ... EN5805300K

At less than £22 the pair, that might be the cheapest option. Certainly cheaper (and better) than buying 3mm sheet steel and spending a day fettling!

EDIT --- On second thoughts, why do you need two? Surely there is some way to 'lock' the spindle and then just one C-spanner should unlock the first lock-nut and once that is released the second would unscrew. You would only need a second c-spanner to hold the spindle steady and you would also need another pair of hands to hold that!!
By sunnybob
#1186962
interesting, but they are in the UK and I'm not.
Also they look like square ended pegs and these collars have 4/5 mm circular holes. The americans call them "pin spanners"

Luckily I have a large metal fabricator in my village and I often scrounge offcuts from him. And its my hobby time, so not such a disaster, even though I would rather be making other stuff.
By AES
#1186976
It's purely a guess on my part, but I GUESS the reason he needs 2 spanners is because the outer nut is acting as a lock nut for the inner. In which case, if assembled properly at the factory, the best way to loosen would be to TIGHTEN the inner a smidgen first (while holding the outer still).

But as sunnybob says he doesn't know which hand the thread is, IMO anyway, he'd be better off finding out which hand that thread is before he starts making or buying tools.

I agree that making spanners out of sheet/plate steel is a bit of a faff, a ring would be better, but as it seems now that they're peg spanners and not C spanners, there MAY be a quicker way (e.g. 2 long-ish silver steel bars of the correct dia). BUT that depends on access, AND those pegs are going to have to fit the holes in the nuts pretty nicely (to avoid graunching the nut holes up).

Perhaps a pic or 2 would help our guessing sunnybob, but I still reckon you need some advice from someone who knows that particular lathe before you go much further.

AES

Edit for another thought: A lot of angle grinders use peg spanners to tighten the nut against the disc. have you got an angle grinder? Does your peg spanner fit by any chance? :D
By J-G
#1187012
I know we are all guessing - and I certainly made the assumption that the lock nut was the type A in my attached drawing (even though sunnybob said 4.5mm dia!!!).

An angle grinder 'PIN' spanner will have two holes as type C and is unlikely to be used when two nuts are locked together.

I now suspect that Sunnybob has type B.

I also consider that left hand threads are unlikely since the whole point is that TWO nuts are locked together and it's not a matter of potential 'unscrewing' in operation, just a matter of maintaining a location.
Attachments
Lock Nuts.png
By sunnybob
#1187047
JG... yes they are type B in your diagram.
Diameter 32 mm with three evenly spaced circular holes of 4.5 mm.
Each collar is about 25 mm thick.

They are a bearing pressure adjusting nut and a lock nut.
Obviously there is only one thread on the shaft, but none of it is visible. They did not respond to a fair bit of pressure exerted with pipe grips (in both directions). i have surfed the web and found a couple of "i didnt have the spanners so didnt bother", and one that said he made his own spanners but did not describe direction of turn,so not very helpful.

I've since found out the lathe is even older than I thought, apparently that model was stopped in 1990.
The lathes overall condition is very good but as those bearings havent seen grease for 30 years or more, and there is a very slight rubbing, I want this done.
By J-G
#1187068
I've just 'Googled' HobbyMat Lathe and found a manual
http://www.bazmonaut.com/wp-content/upl ... nual-b.pdf

Page 20 describes how to adjust the main spindle and says "Unscrew rear nut by turning it in a counter-clockwise direction;"

This confirms (to me) that it is a right-hand thread.
By AES
#1187074
Again, IF it's any help, I agree with JG - my own guess was that since lathes are supposed to happily run in either direction, the chances are high that the headstock thread is a normal RH thread. Especially so since we now see that the nuts are type B (where did you find that diag JG, it's a good'un?).

There MAY even be 3 nuts, which would indicate a pair of bearings, probably ball, maybe even roller type, or taper roller type, pre-loaded (a certain torque setting) then the whole caboosh retained in the head hosing by means of torque loading the outer (3rd) nut. But this is getting complicated, and sounds more like a high-grade industrial machine, whereas I THINK your machine is aimed at the hobby market bob.

All this guess work is NOT good IMO, you really do need advice from an owner of the same lathe, or even better, a Manual for it. Did you try that Lathes web site? Apparently a fount of good lathe info.

Can really only suggest you carry on googling to get the right info, rather than "maybes".

Sorry, can't help more, good luck mate.

AES
By AES
#1187076
Well found JG! JUST what the Dr ordered!

AES