Cracks in mill-to-lathe attachment Hobbymat MD65/BFE65

[Peter Andersson 1Participant @peterandersson1]

[Peter Andersson 1Participant @peterandersson1]

Hi everyone – first post here!

I have acquired a Hobbymat MD65/BFE65 lathe/mill. On closer inspection, I found that the attachment bracket for the mill onot the lathe has 2 cracks in it. The material is aluminium, and I'm now wondering what can be done to establish stability and rigidity as far asconnecting the mill to the lathe please?

Any advice is greatly appreciated.

Edited By David Clark 1 on 17/04/2012 17:02:31

[Ady1Participant @ady1]

Make a new one on your lathe

No. I'm not joking, this is EXACTLY what they are for

Make a standard replacement, then make an improved replacement to improve the machine

[Peter Andersson 1Participant @peterandersson1]

Hi Ady1,

I see your point,but this attachment actually is a cast block of aluminium, approx 7"x5"x3.5". I'm not knowledgeable enough to be able to procuce this size & shape. I was thinking along the lines of whether there's a possibility to repair (weld?) these cracks, or if I could have a steel backing plate made to support the "wings" of this block (i.e.the parts of the attachment bracket with the holes and bolts in it)?

Edited By David Clark 1 on 17/04/2012 17:03:23

[Russell EberhardtParticipant @russelleberhardt48058]

I'd make a replacement one in steel to give it a bit more strength. I presume that it is attached to the lathe by bolts through the two holes on the left. If that is the case the damage was almost certainly done by over tightening the bolts.

You should be able to set the block up in the four-jaw chuck to face it and bore all the holes.

Russell.

O.K. just seen your second post, not quite so straightforward.  How about making a thick steel plate so that the broken part is sadwiched between the lathe bed and the plate?

 

Edited By Russell Eberhardt on 17/04/2012 16:42:28

[Robert DoddsParticipant @robertdodds43397]

Peter,

I think your two tone yellow might confuse some into thinking its just a little boss thing.

It's part of the main casting however, that bolts to the lathe bed and will need some reinforcing.

I'm not sure of the detail of the casting on the underside but my starting point would be to see if a 12mm strap of steel could be permanently bolted accross the whole mounting face replicating the mounting holes and then cut off this weakened lug.

You could always try for a 2nd hand one from a site like this. Amazing what comes out from under the bench

 

Regards Bob D

I too see the new posts with photo detail. How many of those bolts are attachment bolts? Are some just used to jack off and align the base to set it up square. It might suggest that the whole thing has been a bit brutally tightened at some time.

The basic repair principal is still valid.

Bob

Edited By Robert Dodds on 17/04/2012 16:56:46

[David Clark 13Participant @davidclark13]

Hi There

I would get a couple of bits of angle iron and bolt one to each side face and the sides of the mounting lug.

Could square up the sides of the casting with a file.

regards David

[KMPParticipant @kmp]

Hi Peter,

A common problem with these excellent little machines, see Lathes.co.uk on the Hobbymat page – last paragraph before the pictures. Simple steel block or "L" machined (filed) to match casting angle, in front of the broken one and thick enough (long enough L leg) to tap for a couple of bolts to attach through the hollow casting. Back this up with a strap inside the casting to spread the load. Many variations as already suggested.

While the original is a nice lightweight casting there is no reason why a steel block of less refined shape would not work much better when you have got the hang of milling. If you fancy trying for a spare try these people :

http://www.mattharvey.com/esselengineering/

They do stock some spares for the Hobbymat and you won't be the first person to ask.

As an aluminium casting it could certainly be welded with care and the right kit but I would still strengthen it with some type of strapping and be very careful with the adjusting screws. For more information on the Hobbymat, try this group:

http://groups.yahoo.com/group/Prazi_mill_lathe/

Regards

Keith

[Peter Andersson 1Participant @peterandersson1]

Posted by Robert Dodds on 17/04/2012 16:45:21:

I too see the new posts with photo detail. How many of those bolts are attachment bolts? Are some just used to jack off and align the base to set it up square. It might suggest that the whole thing has been a bit brutally tightened at some time.

The basic repair principal is still valid.

Bob

Edited By Robert Dodds on 17/04/2012 16:56:46

Hello Bob, Russell and David, and thanks; 2 bolts on each side of the main part, (where the mill column slides in) are connecting bolts, the other 2 (1 on each side) is for levelling. The 2 connecting bolts (on one side) can be seen in my first picture, as well as the fracture lines in the aluminium next to both of them. Definitely a case of overzealous tightening. I was thinking along the lines of a steel strap too and/or angle irons to try to offload the fractured bit and prevent the other side to go too.

Cheers /Peter

[Peter Andersson 1Participant @peterandersson1]

Thanks KMPand everyone else who replied – so much good input and so fast

I've made a mistake in my info…the two bolts with the fracture lines next to them are actually alignment bolts too. The actual fastening bolts ae not visible in that picture, since I removed them.

Here's a picture showing those with the corresponding little plate that goes on the inside of the lathe bed. Apologies for that. At the same time, with this design and the aluminium, it's not that hard to see how this might eventually happen.

Edited By David Clark 1 on 17/04/2012 18:32:36

[Mike RoseParticipant @mikerose73833]

Peter I have one of those unused (by me). I will check it is undamaged tomorrow . If you are interested you can have it for£5 plus postage.

Mike

[Ady1Participant @ady1]

I would get a couple of bits of angle iron and bolt one to each side face and the sides of the mounting lug.

lol.

I thought it was a wee square of metal

Davids idea sounds like the best to me.

Try and beef things up by sandwiching the stress points between angle iron and flat steel plate to spread the load around the aluminium

[Peter Andersson 1Participant @peterandersson1]

Posted by Mike Rose on 17/04/2012 23:28:39:

Peter I have one of those unused (by me). I will check it is undamaged tomorrow . If you are interested you can have it for£5 plus postage.

Mike

Hello Mike!

That was fantastic news!!! Thank you very much!

/Peter

[SpringbokParticipant @springbok]

Now there Peter is a model engineering friend indeed.

Bob

[Russell EberhardtParticipant @russelleberhardt48058]

Just make sure you don't overtighten the new one

Russell.

[Mike RoseParticipant @mikerose73833]

Peter

I have sent a PM to you

[Peter Andersson 1Participant @peterandersson1]

Hi Mike,

I've replied by sending you a PM – and MANY THANKS again!!!

/Peter

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