Cleaning up a Hobbymat MD65 lathe

Hi guys,
I picked up a Hobbymat MD65 mini-lathe the other week, old and paint- chipped but otherwise in reasonably good nick. Zero play on the headstock
spindle, and it works pretty nicely but for a few things...
* The handwheel on the compound slide is incredibly stiff. They move, but not particularly easily. Basically, it's a total pig to move towards/ away from the workpiece, or horizontally side-to-side. Can these be loosened a little?
* Same goes for the leadscrew handwheel -- engaging the motor drive for the leadscrew works fine, but trying to make that thing turn by hand is a nice easy way to make one's wrists and palms quite sore!
* The graduated dials tend to stick, making it difficult to move e.g. the compound a specific distance.
* While I've got the basic parts (chuck keys, thread cutting gears) I'm missing a few of the other accessories: - Chuck jaws (I've got the ones which are highest at the centre of the chuck -- externals? -- but not the others) - Chuck guard - Machine vice (but I have the angle plate to mount it)
I'm thinking most of this is down to dried oil and grease in the workings and possibly loose nuts on the handwheels, but I suspect some of the stiffness is down to badly adjusted tensioning components. I get the impression that while the lathe has been fairly well taken care of, it's been left sitting for a while and I get the impression it could do with a good clean/lubricate/adjustment session.
Also, a lot of the set-screws seem to have gotten quite black and mucky, as has most of the bed and the compound (there's a section of bright metal where the rotating section of the compound sits). Is this a cause for concern? It doesn't look like rust, more like staining.
Has anyone done any maintenance on an MD65 (which is apparently similar to a Prazimat)? Is there anything I should be especially careful with, or shouldn't even attempt to repair?
Do I need to use specific types of oil or grease to lubricate the various moving parts, or will normal 3-in-1 oil and grease suffice? (I have some Comma lubricating grease in the shed, amber coloured and a consistency slightly thicker than green Swarfega -- the 3in1 is the usual "comes in a white plastic bottle" stuff that looks like.. well.. oil)
I did note with some amusement that the manual suggests petrol as a cleaning solvent and warns against its use on "painted or bright metal parts". Is this still the best stuff to use, or should I use a different solvent instead?
Thanks, Phil.
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Hi Phil, I have had a MD 65 since new must be 30 years.
On 04/08/2011 11:48, Philip Pemberton wrote:

The compound handle is just too small, I replaced the cross slide handle will a made one out of 75mm aluminium, and put the cross slide handle on the compound I also fitted a crank handle to the leadscrew handle giving about 60mm rad.

The dials are fitted with flat springs, sounds like they needs a good clean.

Those are the internal jaws. Spares are available from Essell Eng. http://www.esselengineering.co.uk

Sounds like it ;)

The screws started off black, the bed ect. should be bright or at least matt, try wire wool with the solvent of your choice.

The electrical switches can be a bit delicate but everything else can be treated like any other metal item.

I use Castrol X on mine but that's because that's what is in my oil can ;}

What ever you would normally use for degreasing have should be fine.
Regards Colin Docherty
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On Thu, 04 Aug 2011 14:46:40 +0100, Colin Docherty wrote:

Well, I've just finished tearing it apart and giving it a good clean. The main bearings came apart fairly easily after the two (completely round!) locking nuts for the main shaft were "persuaded" with a set of mole- grips. I did notice there three holes drilled into the round section; is there a dedicated tool for removing/reinstalling these?
I also noted that there was no "chuck retaining ring" -- the chuck was instead held into the flange with three bolts (permanently mounted in the chuck) and matching nuts and washers on the back of the flange... Slight deviation from the manual but nothing major.
What does concern me is the carriage handle (the one which moves the carriage left and right). I can get the nut off the threaded end of the leadscrew, but the handle itself won't budge. Nothing I've tried seems to loosen it...
Problem is I at least need to tighten the handle to get rid of the 1cm gap (and ensuing play), and ideally remove the handle to clean all the thick black gunge out of the graduated wheel. Is there some secret to doing this? The manual is rather... unclear as to how this is done.
Thanks, Phil.
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Yup, you're definitely a beginner! :-)
We must be thankful that you're not a medical doctor!
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On Mon, 08 Aug 2011 07:57:07 +0100, anon and off wrote:

Indeed.
But only after I exhausted all other avenues -- basically everything in the Haynes manual I had to hand. Penetrating oil, WD40, light heat from a blowtorch (I figured it would make the metal expand, thus loosening the joint).
So what is the proper tool to use for removing Hobbymat driveshaft locking nuts?
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Philip,
I have not seen the Hobbymat headstock, but I'd bet a substantial sum that the 3 holes you mention are made for use with a special tool. You don't mention whether the holes are on the face or circumference of the nut. If they are on the circumference, a C spanner (or hook spanner) is the thing to use, one of these:
http://www.wixroyd.com/en/catalog/standard-parts/hand-tools/hook-spanners /95450
If they are on the face, you need a tool that looks a bit like a catapult with pins on the ends. However, there would more likely be 2 holes at 180 degrees for use with these, so I guess the former is more likely.
What I'm sure is not intended, at least by the maker, is to use a Mole Wrench (Vise-grip for US readers, IIRC). This will cause cosmetic damage to the outside, and worse might distort the nut.
David
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David Littlewood

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David Littlewood wrote:

The holes are on the circumference, and the C spanner type shown (with a pin nose) is the correct tool to use.
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Venlig hilsen/Best regards
Erik Olsen
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On Mon, 08 Aug 2011 19:26:06 +0200, Erik Olsen wrote:

Specifically, a 30 to 32mm C-spanner ("hook spanner") with a 4mm pin.
My order from Thanet Tool Supplies arrived this afternoon -- a set of letter and number punches, the aforementioned C spanners, a Zeus Precision data chart booklet and some other bits and pieces.
For anyone else working on a Hobbymat, they're made by Gedore. Thanet's part number is GED40Z030032 -- "30 to 32mm C. Spanner / Hook Spanner With Pin".
After a little more work I've managed to get the lock nuts tightened (and they can be loosened too -- que surprise!). I think I've got them swapped over or one is the wrong way round; they don't quite meet in the middle, there's a small gap between the nuts.
The leadscrew handle is still refusing to come off the thread, even with the auto-feed engaged. Blah. I might try a few different change gears to find one which provides a bit more resistance. If all else fails the "plan of last resort" is to buy a replacement, hacksaw most of the way through the handle, then split it in two by driving a chisel into the gap... I *really* don't want to do this, though.
So I'm almost there... key word: "almost".
Once I get this sorted, I'll probably look into fitting a quick-change toolpost and (maybe) a 4-jaw chuck... assuming I can find one of each which will fit the Hobbymat.
All adds to the fun, I guess...!
Cheers, Phil.
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Are you sure it doesn't have a pin in it?
David
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On Fri, 12 Aug 2011 01:29:56 +0100, David Littlewood wrote:

Absolutely sure. There isn't one on the outer circumference, and there isn't one called out in the parts diagram.
I'm bringing the lathe into the house ("when SWMBO is away, the geek will play!") so I can have a proper go at taking the handle off...
No, I won't be hacksawing the thing apart....
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Hi Phil,

And your RL job is butcher ????. You will bend the leadscrew before you can split the handle.
Put something, a bit of floorboard, piece of steel plate on the bed between the saddle and the headstock, wind handle and total resistance is achieved. ;) If you cannot get the handle unscrewed by tapping on it,try chain wrench, stilsons with a strip of thin metal to protect handle,drilling a couple of say 6mm holes through the face of the handle fit pins and use a crowbar. NO hacksaw and NO chisel,please.
Regards Colin.
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On Fri, 12 Aug 2011 12:03:02 +0100, Colin Docherty wrote:

Point noted.

*face hits desk*
Yep, that'll do it. And the previous tenants of the house were so kind as to leave a load of thick, heavy steel angle in the back of the garage. I reckon a few pieces of that (padded with offcuts of laminate floor to avoid damaging the lathe) should provide sufficient.. ahem.. "resistance"
This is all pretty new to me... most of my experience is in plastic and wood work. I've done basic sheet metal (cutting with tinsnips and/or a Dremel) but that's about it. Suggestions for good books on metalwork would be much appreciated!

Would a sharp tap with a Wilko 454g rubber mallet be considered excessive force in this situation?
Thanks, Phil.
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The Amateurs Lathe by Lawrence H Sparey was the book recommended but that was published in the 1950tys. Have a look at the Workshop Practice Series , Amazon do them.

No but personally I would use the copper face on a small Thor copper hide mallet. Rubber is fine if it is just grunge you are over coming but copper or steel but be better to shock it loose.
Regards Colin
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Try www.camdenmin.co.uk they usually have them.
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A book worth looking at in the Workshop Practice series is the No. 34 by Harold Hall, 'Lathework A Complete Course'. An all round book is Ian Bradleys 'Amateurs Workshop'.
John H
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Well, it's taken two weekends, but I've finally got the MD65 into a workable condition... Thus far I've:
* Stripped and cleaned everything in the gearbox except the motor (which appears to be quite difficult to remove)
* Disassembled, degreased and re-oiled (or greased where appropriate) all the bearings. I started with the drive shaft and moved on to the leadscrew support bearing (the ball-bearing at the front-left).
* Replaced a sheared taper pin on the cylinder which supports the left leadscrew bearing. Lord only knows how THAT happened... Had to drill the blasted thing out...
* Stripped and cleaned the slide. Covered the table in metal swarf. All checked and realigned. The handle on the saddle (the one with two handle- pins) is a bit stiff though. Might need to put a bigger handle on that...
* Leadscrew handle removed, cleaned, reinstalled, bearings lubricated and adjustments adjusted. It isn't as stiff as it was, and seems to hold its position. The nearly 2-turns of "delay" between changing direction and the carriage moving is now down to virtually zero.
* Filed and sanded (600grit wet-dry paper) some burrs off the shafts and wheels in the power-feed section. The power-feed isn't sticking now, but it's still a pig to switch on (not so bad to switch off though)
Now I just need to replace the two mangled drive-shaft nuts, the leadscrew handle (plating's coming off, handle bent, both springs missing from the measuring gauge) and a few missing screws.
On the shopping list: quick-change toolpost (if I can find one which will fit, will be calling Chronos on my lunch break tomorrow), some better cutting tools (having just had a Clarke one explode into a million pieces), a threading die holder and maybe a knurling tool.
Oh, and a couple of Workshop Practice Series books (time to cash in a few of those credit card points for Amazon vouchers...)
Thanks to everyone for the help, pointing out my stupidity, suggesting better solutions and so on. Your help, comments and suggestions have been most appreciated!
Cheers, Phil.
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Philip,
Just so you know when you come across the term in books and magazines, the "delay" is called backlash.
Unless you are using a DRO which reads directly from a scale on the moving part, you must always approach a setting on the dial from the same direction - even "virtually zero" backlash will cause some error if you don't observe this rule. Best practice is to approach in the direction which is putting on a cut (i.e. normally inwards or towards the headstock). If you turn the handle too far and miss the dial reading you are aiming for, back off until the carriage starts to move back, and then go forward again to the right position.
David
--
David Littlewood

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A 'c' spanner.

That's how mine is.

Engage feed lever,{do not turn lathe on} tap handle gently, it should unscrew. Failing that perhaps mole grips and a stilson wrench ;)

The manual like all such documents assumes that nuts will come undone and that screw heads never break, rust never ever happens.....
Regards Colin Docherty.
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Have you ever used a lathe tool post grinder? when you install it on cutter holder.The lathe tranform into a cylindrical grinder which can grind both internal and extarnal with high precision.
http://www.thorgrinder.com/productshow/?89-18-Lathe-tool-post-grinder.html
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thorgrinder
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tool post grinder is very widely used in my country.
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