Hobbymat MD65 lathe refurb

[Jon FairbanksParticipant @jonfairbanks32181]

feed control lever

[Jon FairbanksParticipant @jonfairbanks32181]

I recently acquired an old (1979 vintage) Hobbymat MD65 lathe. The lathe was still in the Styrofoam packaging, but had some damage to the headstock end.

The power feed coupling was missing but a quick search for the part number 3800-0211 turned up a post by a member on this forum and eventually a drawing of the part. I made the part but now can't figure out how the coupling control lever is supposed to engage the coupling to the change gears.

It looks like the design of the control lever changed over the years. This is what I have:

The control lever is the part with the two pins sticking out of the top. Is this missing some piece? Or am I missing something as to how it pushes the coupling into the change gear?

Newer models appear to have this design (parts 8,9,etc):

Thanks,

Jon

[BazyleParticipant @bazyle]

AH, your vertical cylinder 9 is upside down. The off centre pin fits in a corresponding hole in the section 8 below when the system is out of gear. You lift it up to clear the pin to allow it to be rotated such that the horizontal pin 27 which engages the groove in the dog clutch can move the clutch into engagement. It is spring loaded so it remains engaged only by friction of the vertical pin on the smooth top of part 8 and can be flipped out of gear so the pin drops back into its hole locking it off.

[BazyleParticipant @bazyle]

can't see from the photo but you do have two parts 8 & 9 don't you?

[Jon FairbanksParticipant @jonfairbanks32181]

I only have the one part. The top of the one part is almost to the center line of the lead screw.

The screw that locks the part to the rod coming out of the bed of the lathe is on the side of the part. On the newer versions the screw appears to be on the bottom of the part (#22 in the exploded diagram above).

[AjohnwParticipant @ajohnw51620]

This might help. The pin drive a dog clutch that form memory is under the headstock  lead screw cover. However looking at this image the dog clutch engages the gear on the leadscrew so maybe they have changed.

John

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Edited By Ajohnw on 28/04/2016 00:03:13

Edited By Ajohnw on 28/04/2016 00:04:38

Edited By Ajohnw on 28/04/2016 00:05:20

[LambtonParticipant @lambton]

Jon,

I have sent you a PM which you will find helpful. Please check your inbox on the green line at the top of the home page.. It should be flashing.

Eric

[AjohnwParticipant @ajohnw51620]

I've just received a pm from you Eric. It's not me that needs the details.

However why email some one pictures when they could be put in an album on this site and shown in the thread so if some one else has the same problem in the future all of the information will be there.

The only problem with albums and showing the shots in the thread is that they must be in it before starting a post.

John

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[LambtonParticipant @lambton]

Sorry John I meant to send it to Jon Fairbanks the originator of this post.

Eric

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, the dog drive control on my Hobbymat appears to be the same as Jon's, but alas I don't have the top part of mine either.

There is no hole in it for the pin that engages with the dog drive or for an operating lever.

Regards Nick.

[BazyleParticipant @bazyle]

You can see the line in Ajohnw's photo indicating the two parts 8 & 9. It looks like the design change made the bottom part 8 much shorter. Nick and Jon seem to have a longer post with a central pin ready to be used as a pivot for a lever that engages the slot in the dog clutch. About 10 seconds to design something and ten minutes to make.

[Jon FairbanksParticipant @jonfairbanks32181]

I took the advise from Bazyle and made something to work rather than copy the OEM design.

This is what I came up with:

I pulled out the 4mm and 5mm pins from the original part. The 5mm was tapped for a M6 X 1.0 screw. The 4mm was tapped 10-32 for a spring loaded ball detent. The new top piece has a 6mm axial thru hole and a 4mm cross hole. A 4mm dowel pin was inserted into one side of the cross hole and the other side was tapped for a 10-32 thumbscrew. The final step was to put a small drill point to coincide with the engaged position of the coupling dog.

Works well. The detent acts to keep the dog from disengaging. This vintage MD65 has a hole in the belt cover so the thumbscrew must be removed before the cover can be removed.

[BazyleParticipant @bazyle]

Nice work Jon. Perhaps there are hundreds of the older model out there needing this. I'm a bit surprised though that there is an older model. I got mine in about 1981? at the first ME show it appeared at.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Jon, agree with Bazyle, might get round to doing that to the one I have. Mine didn't have the guard, so I should be able to make one with a slot in like most of them you see.

Regards Nick.

[Jon FairbanksParticipant @jonfairbanks32181]

Judging by the variation of on/off and forward/reverse switches I've seen Hobbymat was willing to make changes to some parts of the lathe. I would imagine that those changes were made as improvements, not just cost reduction. The early control lever design must have been prone to losing pieces as is evident by the lathe I have and the one that Nicholas has.

[AjohnwParticipant @ajohnw51620]

My memory of the Hobbymat dog clutch is pretty fuzzy. I did have to dismantle it a couple of times after screw cutting with it using motor power. Some how the tongue on the clutch would tighten up and need cleaning up with a file. As this involved continuously taking a cut and reversing the lathe it had nothing to do with engaging while the lathe was running but it could have been part down to using power feed and just showed up after screw cutting.

It did good accurate work. One problem did show up for some one. I part exchanged it at Graham Engineering aka Alpine House for another machine. Next time I went in i was accused of selling it with a crack in the top of the compound slide. As far as I know I didn't but do be careful when tightening the screws down on tools in the "toolpost". It had the top hat type that clamps directly onto the top of the slide. Personally I would also be careful with the other type.

Not being entirely happy with my current 2nd lathe I have recently bought another one. Maybe I have got it right this time but if not costs will be low if I decide to sell it on. It did come with the right bits but no collets. I suspect it will need new headstock bearings but part of me likes working on machines just to see what class of work I can get out of them.

John

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Edited By Ajohnw on 02/05/2016 10:21:44

[Skye LeakeParticipant @skyeleake61603]

Hello all,

I am missing the power feed coupling (P/N: 3800-0211) on my Hobbymat MD65. Is the drawing of this part still around so I can create the part? I cannot seem to locate any spec sheet on the part with critical dimensions. Or even better yet, if anyone has found a way to source this part… Any help is greatly appreciated.

Thank you in Advance,

Skye Leake

[BazyleParticipant @bazyle]

There aren't any drawings. I take it you mean the dog with the groove in it that has a keyway to fit the leadscrew shaft end as shown in some of the pictures above. Or do you mean the free running hub the big white gear above is fitted too. Either way I can measure it up tonight if John doesn't this afternoon.

[Skye LeakeParticipant @skyeleake61603]

My apologies, I meant the free running hub with the groove that engages the pin on the control lever and the dog on the lead-screw side.

http://www.model-engineer.co.uk/forums/postings.asp?th=83750

-Skye Leake

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Skye Leake, is this the drawing you are looking for?

Regards Nick.

[Skye LeakeParticipant @skyeleake61603]

Yes Indeed,

Thank you to all that replied!

– Skye Leake

[Steve ColeyParticipant @stevecoley62112]

Hello all…my 1st post and looking for a little help.

Thought i'd tag onto this thread as it is exactly what i'm looking for.

I recently got myself an old MD65 – bits missing and a little refurb has been required but almost there..

I'm now just missing the dog coupling as shown above…can anyone tell me the metal it is made from..if i can't obtain one i'll have to have a go at making it myself..

I'm a complete novice so please be kind….

Thanks,

Steve

[Neil WyattModerator @neilwyatt]

Hello Steve,

Welcome to the forum!

Your post might get overlooked here, if this happens you might want to start a new thread for your question.

Neil

[John HaineParticipant @johnhaine32865]

A bit of mild steel bar should do…

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Steve, EN8 would be better than normal mild steel. Silver steel as supplied should also be OK, but would be a bit costly for that size.

Regards Nick.

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