Cleaning up a Hobbymat MD65 lathe
Philip Pemberton
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.
Colin Docherty
I have had a MD 65 since new must be 30 years.
On 04/08/2011 11:48, Philip Pemberton wrote:
> 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?
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.
>
> * 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.
The dials are fitted with flat springs, sounds like they needs a good clean.
>
> * 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)
Those are the internal jaws. Spares are available from Essell Eng.
http://www.esselengineering.co.uk
>
> 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.
Sounds like it ;)
>
> 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.
The screws started off black, the bed ect. should be bright or at least
matt, try wire wool with the solvent of your choice.
>
> 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?
The electrical switches can be a bit delicate but everything else can be
treated like any other metal item.
>
> 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 use Castrol X on mine but that's because that's what is in my oil can ;}
>
> 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?
What ever you would normally use for degreasing have should be fine.
Regards Colin Docherty
Philip Pemberton
>> 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.
>
> Sounds like it ;)
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.
anon and off
news:4e3f0be6$0$2699$c3e8da3$33a0...@news.astraweb.com...
> 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.
Yup, you're definitely a beginner! :-)
We must be thankful that you're not a medical doctor!
Philip Pemberton
>> round!) locking nuts for the main shaft were "persuaded" with a set of
>> mole- grips.
>
> Yup, you're definitely a beginner! :-)
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?
David Littlewood
Pemberton <usen...@philpem.me.uk> writes
>
>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?
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
--
David Littlewood
Colin Docherty
>
> 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?
A 'c' spanner.
>
> 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.
That's how mine is.
>
> 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...
Engage feed lever,{do not turn lathe on} tap handle gently, it should
unscrew. Failing that perhaps mole grips and a stilson wrench ;)
>
> 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.
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.
Erik Olsen
> 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
The holes are on the circumference, and the C spanner type shown (with a
pin nose) is the correct tool to use.
--
Venlig hilsen/Best regards
Erik Olsen
Philip Pemberton
> The holes are on the circumference, and the C spanner type shown (with a
> pin nose) is the correct tool to use.
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.
David Littlewood
Pemberton <usen...@philpem.me.uk> writes
>
>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.
>
David
--
David Littlewood
Colin Docherty
> 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.
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.
Philip Pemberton
> Are you sure it doesn't have a pin in it?
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....
Philip Pemberton
> You will bend the leadscrew before you
> can split the handle.
Point noted.
> 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. ;)
*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!
> If you cannot get the handle unscrewed by tapping on
> it,
Would a sharp tap with a Wilko 454g rubber mallet be considered excessive
force in this situation?
Thanks,
Phil.
Colin Docherty
>
> 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!
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.
>
>> If you cannot get the handle unscrewed by tapping on
>> it,
>
> Would a sharp tap with a Wilko 454g rubber mallet be considered excessive
> force in this situation?
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
anon and off
news:8Rs1q.126679$T85.1...@newsfe19.ams2...
>> 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!
>
> 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.
Try www.camdenmin.co.uk they usually have them.
John H
> >> 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!
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
Philip Pemberton
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.
David Littlewood
Pemberton <usen...@philpem.me.uk> writes
>
>* 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.
>
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
thorgrinder
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
--
thorgrinder
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thorgrinder
tool post grinder is very widely used in my country.