Absolute beginner, just bought a cheap lathe

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Absolute beginner, just bought a cheap lathe

This topic has 25 replies, 15 voices, and was last updated 25 September 2021 at 10:51 by Chris Drew.

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19 September 2021 at 16:43 #10965
Chris Drew
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@chrisdrew10685
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19 September 2021 at 16:43 #563456
Chris Drew
Participant
@chrisdrew10685
Hi All,

completely new to engineering of any kind but always wanted to have a go so I recently bought a Hobbymat MD65 lathe just to have a play and see what I could make. Unfortunately being new and the seller not being up front I have just found out that the cross slide is broken, the captive nuts holding the tool post have pulled out rendering the lathe pretty useless. I want to try and fix this as my first job and was wondering if anyone else uses this kind of lathe and has had a similar problem? If so are there any fixes other than trying to find a replacement? Thanks for any suggestions!
19 September 2021 at 20:03 #563487
Chris Evans 6
Participant
@chrisevans6
I know nothing about your model of lathe but an approximate location my help, there my be a forum member close by.
19 September 2021 at 20:43 #563490
Grotto
Participant
@grotto
Hi Chris,

There seem to be a few owners of MD65's on here so I'm sure you'll get some help. If you add a photo of the offending part(s) it would be good.

I’m just wondering if it's the cross slide which is faulty or the top slide (which is what tool post bolts to). I may have my terminology mixed up as I no expert.

If it is the top slide, you could just remove it and mount the tool post on the cross slide.

I've done that with my lathe, I just have a spacer under the tool post. I only ever use the top slide for cutting tapers and threads larger then about 1.5mm pitch.
19 September 2021 at 21:06 #563492
Chris Drew
Participant
@chrisdrew10685
See, I said I was a complete novice, of course you are correct it’s the top slide which is broken! I had heard of just removing it but then I couldn’t see how the tool post would mount as it uses 2 m8 bolts to attach to the top slide and of course there aren’t any mounting points on the cross slide. BTW i am located just outside Scunthorpe in North Lincolnshire…. The height of the tool post also relies on the top slide so without it the tools would be very low and there isn’t enough adjustment to raise them. I had thought of drilling and tapping the other end of the top slide and just reversing it which I can’t see why it wouldn’t work…
19 September 2021 at 21:33 #563495
DiogenesII
Participant
@diogenesii
Hi Chris,

..if you mean the topslide, I don't think it's unheard of for that to happen – mine had had exactly the same problem when I bought it, the previous owner had driiled through, counterbored the underneath, and fitted flanged bushes with threaded holes to anchor the toolpost.

HOWEVER I might be inclined to fit a Helicoil-type thread repair if I was to do the job – it's simpler and results in a repair that is at least as strong as the original fitment – the thread insert may need to be dressed back with a small grinding wheel (Dremel?) after fitting, as the slide is a bit on the thin side.

I'll post some picks of the repairs to mine in the morning.

They are good little lathes, they have a few quirks but are capable of doing very respectable work – although they are well built, they are susceptible to damage if mistreated – it's definitely worth buying a manual, and having a look through previous threads using the 'search' box at the top of this page..
19 September 2021 at 21:55 #563498
Bazyle
Participant
@bazyle
The original round toolpost is a bit odd anyway. People do try to do the tool clamping bolts too tight so can damage stuff. Plus the slide is quite thin and flexible so if you overdo it the casting bends and jams.
20 September 2021 at 06:20 #563518
Pete Rimmer
Participant
@peterimmer30576
I would go with the above solution and helicoil the stripped holes. First though I would put a straight edge across the slide top and make sure it isn't bowed out slightly from whatever abuse caused the stripped threads.
20 September 2021 at 08:00 #563523
Grotto
Participant
@grotto
Hi Chris,

I made a packing block out of a lump of cast iron.

His attaches to the cross slide the same way as the top slide did, and is drilled & tapped to allow me to bolt my tool post to it.

I'm surprised at the improvement in rigidity with the top slide gone. It was only meant to be a temporary set up, but it’s become fairly permanent.
20 September 2021 at 08:06 #563524
DiogenesII
Participant
@diogenesii
Posted by Chris Drew on 19/09/2021 21:06:02:

…I had thought of drilling and tapping the other end of the top slide and just reversing it which I can’t see why it wouldn’t work…

If you do that, it'll put the gib on the 'thrust' side of the slide and the forces of cutting will be concentrated on the points of the adjustment screws that bear on the gib strip..

For the record, here are photos of an ugly repair that had been carried out by a previous owner of mine – the bolts securing the tool holder are M10, which suggests to me that it probably wasn't his first attempt..

FWIW having slept on it, I stand by the Helicoil suggestion..
20 September 2021 at 09:33 #563528
Ady1
Participant
@ady1
I bought a total dog as my first lathe too and it took me a long time to sort it out

You'll get there in the end but it will hold you back in some respects

On the other hand it will teach you whether you want to keep going with this hobby, even with decent gear it's quite a long hard and winding road

GL
20 September 2021 at 10:17 #563536
Chris Drew
Participant
@chrisdrew10685
I suspect this is beyond saving – when I got it the captive nuts had been welded in but the weld had lifted so the tools could not be mounted securely. Tried re-welding but it's not the easiest material to weld and although it looked OK obviously had not penetrated the material as just lifted again. I do have a similar thickness plate of steel from my hydraulic press which I am thinking I could modify to make a fixed mount for the tool post.
20 September 2021 at 10:22 #563537
John Hinkley
Participant
@johnhinkley26699
Chris,

I can't help with the Helicoil, which I venture to suggest is your best solution, but once you've decided on a course of action and if you need further assistance, I'm not too far away from you just east of Doncaster. If you require any help, drop me a PM with your contact details and I'm sure we can arrange something.

John

OOH! Just posted and seen your photo! Now that HAS been butchered, hasn't it? I think you'll find that the topslide is cast iron – so difficult to weld. You might get away with a brazed repair, but it won't be pretty. If I was you, I'd look around for a replacement in better condition.

Offer still stands, though.

Edited By John Hinkley on 20/09/2021 10:27:36
20 September 2021 at 10:45 #563540
Phil P
Participant
@philp
Just thinking aloud here……but is it possible to reverse it and fix the toolpost at the good end ?

Phil
20 September 2021 at 10:47 #563542
Ady1
Participant
@ady1
That's a mess, a replacement could be hard to find as well

Gasless mig can sort cast iron but you need to get going asap or you'll lose interest

Dump that top slide to one side and make a toolpost for the cross slide which will do 90% of your work anyway

This is an early version I did for myself
20 September 2021 at 11:50 #563557
Nicholas Farr
Participant
@nicholasfarr14254
Posted by Chris Drew on 19/09/2021 21:06:02:

See, I said I was a complete novice, of course you are correct it’s the top slide which is broken! I had heard of just removing it but then I couldn’t see how the tool post would mount as it uses 2 m8 bolts to attach to the top slide and of course there aren’t any mounting points on the cross slide. BTW i am located just outside Scunthorpe in North Lincolnshire…. The height of the tool post also relies on the top slide so without it the tools would be very low and there isn’t enough adjustment to raise them. I had thought of drilling and tapping the other end of the top slide and just reversing it which I can’t see why it wouldn’t work…

Hi Chris, at a last resort you could reverse the top slide and drill and tap the other dove tail to keep the gib strip in the correct side, the downside is the the single hole ((at least on mine) is in the wrong place to get the two holes for the tool post in the same position and you would have to be a bit precise for the little hole for the gib strip pin. The single hole could be used for one of the holes for the tool post but that will mean it will be a little further back and as a result the top slide may engage with the rotating chuck before the tool that you would be using reaches the point that you need to take a cut too, but you could cut the top slide a little shorter, which would be about 6mm to come off, but of course you would loose 6mm of travel of the top slide as well. You can always glue or screw a piece of sheet metal over or those wrecked holes or even use body filler or similar, to stop swarf etc. getting all over the winding thread and filling the cavity.

Regards Nick.
20 September 2021 at 12:58 #563566
Dave Halford
Participant
@davehalford22513
I would cover the hole with a 4mm steel plate held down with four off m6 counter sunk screws into the good iron avoiding previously welded surface as it may be too hard, not too near the dovetails. Then drill two holes in the plate m10 clearance, welding two m10 nuts underneath the plate.

You need sufficiently flat surfaces for this to work properly or you end up over tightening so check the plate for warps before continuing.

My experience with cast iron and welding – you lay some weld on cast and hear a tinkling sound – thats the weld breaking.

You use cheap 90% nickel rods with iron (FE) in them , they weld OK but the weld is too hard for HSS tools. Use expensive 99% nickel rods and everything is good to go.
20 September 2021 at 13:26 #563568
Chris Drew
Participant
@chrisdrew10685
Thanks Dave, my limited knowledge would suggest that now the tool post would be too high and I wouldn't be able to lower the tool enough to centre. I have found a piece of 15mm plate of the correct dimensions and I think for now I will modify this to act as a fixed top slide. I can then look around for another top slide but having read a little more it seems this is a common fault with this machine.

I don't want to take too long to get up and running as otherwise I may get bored and just give up! I'm certain I will have a load more questions!
20 September 2021 at 14:29 #563572
pgk pgk
Participant
@pgkpgk17461
Depending on how it looks like underneath (for room) and how large the base of the toolpost is.. Would it be possible to mill out a neat rectangle that removes all the nasty holes and a rebate around it underneath, then make up a plate the same thickness with shoulders the depth of the rebate, drilled and threaded and mount the toolpost on that? Locktite it in so it doesn't fall of if you remove the toolpost bolts completely.

pgk
20 September 2021 at 14:42 #563576
Howard Lewis
Participant
@howardlewis46836
If you contact, and preferably join, your local Model Engineering Club, someone there will probably be able to help you.

It may either be possible to machine away the damaged ares and insert new material, or even to make a complete new Top Slide.

Find out where and when they meet and go and visit.

You will like minds there who will be willing to help and advise you, not just on this problem, but others that you will encounter non journey into Model Engineering.

If you give your location, there may be someone on the Forum who would be able and willing to help you.

Howard
20 September 2021 at 14:50 #563578
Nicholas Farr
Participant
@nicholasfarr14254
Hi pgk, that would have most likely worked, but if you look at DiogenesII's first photo, you will see that the tools and any shims required sit on top of the slide and the way Chris's one has been attacked with a grinder, won't produce a very good surface for them without a significant overhang.

Just had another look at mine and you wouldn't get a piece wide enough between the dove tails for it to have any surface for the tool to sit on width wise and you would more than likely to have to have it right to the front end for any tool to sit on in that position.

Helicoils or the "Ugly repair" DiogenesII has shown, would have maybe, been the best solution if done in the first instance.

Regards Nick.

Edited By Nicholas Farr on 20/09/2021 15:08:38
20 September 2021 at 18:27 #563603
DiogenesII
Participant
@diogenesii
OOooer.. ..well, a faint ray of hope occurs to me – one of the peculiarities of the Hobbymat is that the topslide and crosslide dovetails share the same dimensions, so a cross slide 'body' will fit on the topslide 'base' – in fact, the topslide body is just a sawn-off cross slide body with different holes drilled in the top of it, and reversed (even the gib-screw holes line up correctly).. ..if you set one on top of the other so that the gib-holes line up you will see what I mean…

Tony Griffiths seems to have some cross-slides, but will charge you…

Lathes.co.uk. Hobbymat Prazimat Topslide Casting…

Heritage Lathes will charge you a bit less for this one from his Ebay shop.. (I've dealt with him, seems a reasonable human being for an Ebay vendor)

Heritage Lathes Ebay Imperial cross slide

..hope the link works.. ..I don't think you need to worry about the Imperial feedscrew, but I guess you might want to check the slide dimensions with him just to be sure..

You'll still have to do some drilling and milling, but I see you have an offer of help..
20 September 2021 at 21:07 #563620
Neil Wyatt
Moderator
@neilwyatt
Best bodge?

Reverse the top slide and drill/tap two new holes in it.

Won't be pretty, but gives you a lathe until you can get a new topslide or fabricate one.

Neil
20 September 2021 at 21:22 #563627
Chris Drew
Participant
@chrisdrew10685
Thanks to all for your suggestions. I have bought a 25mm block of steel which is the correct height for the top slide and am in the process of making a 'block' for the tool post to sit on I've mocked it up with a 20mm piece of steel which I had lying around from my press and this would work other than the tools sitting too low but I may either use the 25mm piece or make up a filler to vive me a better surface finish as I don't have a mill. Either way I hope to up and running this week. Have some new cutting tools arriving and I will try and get hold of some alloy bar to practice / mess about with. I do need to turn a spacer for an engine mount for a Laverda I am rebuilding so that may well be my first project – nice and simple !
21 September 2021 at 23:06 #563801
Chris Crew
Participant
@chriscrew66644
Chris, we almost share the same name! If you are in Scunthorpe I am only a few miles from you just outside Market Rasen. If you want to come over to my workshop sometime I would be willing to help you all I can and repair or re-manufacture the parts for your lathe to get you up and running. Drop me a private message and we can set up a meeting if you wanted.
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