Any ideas how to fix this?

This topic has 17 replies, 10 voices, and was last updated 8 April 2013 at 07:02 by Scott.

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6 April 2013 at 09:12 #116190
Scott
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@scott
Morning all

I've dug out the raraley/never (?) used milling slide for my inherited mini lathe and oh deary me!!! The main body of the thing seems to be reasonably well made and ground all over but the slide/carrier/whatever-you'd-call-it is appalling! Apart from the ugly voids in the casting that won't affect its operation it looks like it has been finished on a linisher. There isn't one flat face on it and not one face is 90 deg to any other. What I would consider to be the most useful reference face is like a banana.

I figure there's not much to lose with the thing and I really need to get an engineering company to mill it all square (I don't have a mill) but I can't find one locally in sticksville, France at the moment so I'd like to try to do something with it myself in the meantime until I can get back to UK.

I ran a milling cutter across it but the cross slide travel is insufficient to traverse the thing completely (see photo). I consdered drilling extra holes in the cross slide to mount the milling slide further over but the cross slide leadscrew nut is in the way. I tried turning the cross slide round but again, not enough travel to get a full pass over the casting.

Have any of you experienced bods any ideas for how I might square this up with the limited facilities I have because I'm a bit stumped?

Thanks

Scott
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6 April 2013 at 09:12 #12110
Scott
Participant
@scott
Mini lathe milling slide
6 April 2013 at 09:41 #116192
I.M. OUTAHERE
Participant
@i-m-outahere
Hi Scott,

Maybe a few more pics of the mounting would help as there may be a few options .

It seens as it is mounted to one side and not utilizing the full travel of the cros slide or maybe not designed for this machine .

I would think that you would want it to center up at about half way of your cross slide travel so you have equal travel on both sides .

You could maybe make a spreader plate to mount it up so the mounting bolts arer away from the cross feed nut etc .

Ian
6 April 2013 at 09:43 #116193
MICHAEL WILLIAMS
Participant
@michaelwilliams41215
H Scott ,

You could with difficulty hand file it all true but probably not worth the effort .

This is what I would do :

(1) Saw off the top and bottom shelf parts and face the remaining plain rectangular surface true .

(2) Depending on thickness of remaining material either bolt on a plain rectangular plate with an arrangement of tapped holes in it which would allow a standard small machine vice to be fitted or tap the holes directly in the parent block .

Regards ,

Michael Williams .
6 April 2013 at 09:46 #116194
Thor 🇳🇴
Participant
@thor
Hi Scott,

I agree with Ian and Michael's advice. If you have – or can make – a flycutter you will be able to face a larger area.

Thor
6 April 2013 at 09:55 #116195
GaryM
Participant
@garym
Hi Scott,

Some ideas here:

**LINK**

Andy posts on here and might have some ideas.

Gary
6 April 2013 at 13:08 #116208
Clive Foster
Participant
@clivefoster55965
Quick'n dirty flycutter is a short holder sticking straight out of the faceplate carrying a short length of round tool steel. Slightly longer solid piece opposite for balance. Tool holds better if you double bore the hole by putting a small hole parallel to the main bore offset by the main bore radius. This gives two line contact opposite the clamp screw instead of the single line you get with a simple round bore. Small hole around 1/4 of main bore diameter seems to be the rule.

If you haven't got the faceplate use a stout bar in he four jaw to carry the tool holder. Flywheel mass is always helpful for getting a good finish on clunk, clunk, clunk interrupted cut jobs. Especially on a mini lathe or anything else which is lightly built.

Clive
6 April 2013 at 13:20 #116209
Sub Mandrel
Participant
@submandrel
Scott,

If you round the end of the cross-slide feed nut and recess the end of the cross slide so it can 'overlap' the back of the index dial you can get 1/2" extra travel.

If the mounting point is too far out from the centre line, you can always fit the cross slide on back to front (I upset Mike Chrisp by suggesting this, but it worked for me).

Neil
6 April 2013 at 13:48 #116212
MICHAEL WILLIAMS
Participant
@michaelwilliams41215
Depending on the actual centre height of your lathe it may be possible to face the block off as a turning operation with block on face plate .
6 April 2013 at 20:42 #116242
Andyf
Participant
@andyf
Posted by Gary Marland on 06/04/2013 09:55:27:

…. Andy posts on here and might have some ideas

Andy chipping in:

The inward travel of the cross-slide can be extended by fitting it with a longer feedscrew. Mike (another contributor on here) did it the proper way, by making an entirely new feedscrew.

I did it the quick and dirty way by threading a bit of rod M10 x 1 LH, and bolting it on the end of the existing feedscrew like this. Not for purists, perhaps, but it seems to work fine. There's no reason why it shouldn't, really.

Of course, you need to check how much overlap will be left between the slide and its base when the slide is as far in as you want it to go, and that you aren’t left with all the gib screws except one in the overhanging part of the slide.

Andy
6 April 2013 at 20:59 #116244
Sub Mandrel
Participant
@submandrel
…or make a custom table for the lathe:

Neil
7 April 2013 at 11:43 #116286
Scott
Participant
@scott
Morning all

Many thanks for all the very helpful replies. I suspect trying to alter the cross slide travel is a lot of work for not much return in terms of extra travel and, as Andy has suggested, the gib screws land up hanging out in thin air.

I hadn't considerd the drastic option of sawing the "Shelves" off but it does seem like a very simple way to to get a true surface. Once I have the ability to mill squarely I can reinstate anything I have sawed off if I find the need later so I think I'll go with this option in the meantime (thanks Michael!) and in the longer term make an adapter as Gray suggested to improve the versatility.

Interesting links Gary and Andy. Cheers for that.

Neil, your boing table looks the business but I suspect I need milling facilities to make one! I'll certainly be doing it in the future though.

Cheers

Scott
7 April 2013 at 11:56 #116289
Russell Eberhardt
Participant
@russelleberhardt48058
Posted by Scott on 06/04/2013 09:12:10:I figure there's not much to lose with the thing and I really need to get an engineering company to mill it all square (I don't have a mill) but I can't find one locally in sticksville, France at the moment so I'd like to try to do something with it myself in the meantime until I can get back to UK.

If you are anywhere near dept 66 PM me.

Machine shops are listed in the "Pages Jaunes" under "Rectification, usinage, fraisage" – hope that helps.

Russell (also in sticksville, France)

Edited By Russell Eberhardt on 07/04/2013 11:57:16
7 April 2013 at 12:22 #116293
Sub Mandrel
Participant
@submandrel
Scott,

I milled the table in the lathe, by clamping it to a 'Peatol' vertical slide which is a lot smaller than yours!

I had to cut the dovetails in two sections, usinga bit of kitchen worktop as a jig to keep the setting. The first one came out perfect, I just couldn't get the second one not to have a detectable join – fortunately that was the gib side where it doesn't matter.

I squared the blank up on the faceplate – this was before I understood the limitations of my lathe!

Neil
7 April 2013 at 19:10 #116311
Scott
Participant
@scott
Ooh 'eck Neil! That looks like it's exploring the limits of the machine right enough! Is it steel or CI?

Russell, I'm in 01-land. 74-land also a possibility but I really hate to admit defeat and give it to someone else unless i'm forced to so I think I'll have a go with the hacksaw and flycutter

Scott
7 April 2013 at 22:27 #116319
Trevor Drabble 1
Participant
@trevordrabble1
Scott, Appreciate I may have got the wrong end of the stick here, but my understanding is that you need to generate some long flat and parallel faces here. How feasable is it therefore to use a sharp tool in a very substantial bar mounted similar to say a boring bar, but with the chuck prevented from rotating. The offending milling slide is then mounted securely on the cross slide, with small cuts being applied to one face at a time as the saddle is wound back and forth, so in effect using the lathe as an old fashioned hand planer. In this way length of cut will not be a problem and , assuming the lathe is already set up correctly, the results should be reasonable enough for your purposes. Trevor.
7 April 2013 at 23:42 #116320
Andyf
Participant
@andyf
Scott, going back to your original plea for help. you said "There isn't one flat face on it and not one face is 90 deg to any other. What I would consider to be the most useful reference face is like a banana."

Which face was that? To me, it looks like the most important faces will be the angled faces of the male and female dovetails, and the flat surfaces either side of them. If those are OK in the sense that each flat surface is (a) co-planar with its fellow on the other side of the dovetail and (b) sits at 90° to the lathe bed when viewed side on, and the angled faces are OK, there isn't too much to worry about. I suppose it would be as well to check that the shelf on which your workpiece will sit is parallel with the lathe bed so that if you put a piece of square bar on it, the front face of the bar is vertical and not leaning backwards or forwards.

Whatever other work you do on the part that slides up or down, every time you fasten the contraption down to the swivel disc in your cross slide you will need to check with a clock that the work is at 90° (or some other desired angle) to the lathe bed as viewed from above, and swivel the disc around until the workpiece is dead on.

None of this helps with the problem of getting the cross slide back far enough, of course.

Andy

Edited By Andyf on 07/04/2013 23:52:42
8 April 2013 at 07:02 #116327
Scott
Participant
@scott
Hello Trevor. Interesting thought. I might try that to see if it's feasible before I saw the lugs off. The lathe is a tad "flexible" though so I'm not sure if it'll like being used as a shaper

Andy, I wasn't very clear there, sorry. I meant reference face for mounting something on the slide. I realise the slide needs clocked perpendicular to the lathe axis every time it is mounted but the upper face of the lower "shelf" seems to me to be the most useful surface and it's not flat which is why I was trying to mill it in the lathe itself to ensure decent alignment. At the moment there is a hump in the middle which means that anything mounted on that surface rocks dependent on which screw is tightened.

Scott
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