Restoration and modifications to a Tom Senior light vertical mill

Hi Miles, Ian

Thanks ever so much for your time and encouragement - Ian if you can easily take a photo or two that would be brilliant but please don't go to too much trouble as I think I can see what has happened (what has not happened) here. That second photo (Ian's post at 18:18) and Miles 9 inch measurement explain everything.

I'm out on the road tomorrow, but there's a sudden attack of enthusiasm on the horizon, as I think I see the answer to something which has been piquing my curiosity for years. It never made sense to me that nearly half the table was out of bounds, and now I think I understand why - and even better what to do about it,

I'll whip the table off tomorrow when I get back and see what it reveals. Keep you posted!

Best regards Simon

Well, nothing venture nothing gained, so I have stripped the table off the cross slide, and suddenly all becomes crystal clear.

Somebody had a major crash (tip over?) and broke the lead nut out of its casting. Somebody else devised a simple fix - put the lead nut in the other hole. What I have been seeing is the consequence of moving the lead nut 7 inches or so to the right.

Here's a closer view of the site of the break.

Which strikes me as relatively easily fixed, though I do need another milling machine to make a flat area each side of the original bore for the nut. I can then make a half clamp and clamp the half nut back where it belongs. I'm toying with whether I can do this with my horizontal mill, don't see why not with a bit of patience.

However the interesting part of the riddle remains, as I believe all the parts are original. There is a number 14 stamped on the main column above the s/no, and the same number is on all of the bits of the knee, including the table and the gib strip. So I'm lead to think that all the bits are there, but not necessarily in the right order.

Keep you posted!

Regards to all

Simon

Simon.

That's very interesting !

Here are some photos of the lead screw nut on mine.Bit late as you have found the problem.Difficult to understand how that damage could occur.

I have about 017" of back lash on my nut.If you ever find a source of new bronze nuts let me know.

Edited By ian j on 03/01/2019 22:04:01

Hi Ian, yes I think your pictures just about seal the diagnosis. You're right though, I can't imagine how someone managed to do this much damage without wrecking at least something major, so I'm scratching my head a bit. I see no evidence of dings or bruises elsewhere, suppose I should be grateful it has survived this well.

I guess it doesn't matter too much, I've just got to get past that and find an honourable fix, even if I have to get someone locally to make the necessary mod's to this casting. I'll keep you posted.

And thanks to Miles for letting me hijack his thread.

Best rgds Simon

Simon,

Crikey! That's pretty definitive! What is left of the riddle? With the nut in its original position, everything is the same as it is on Ian's mill and mine. Isn't it?

Miles

Missed your last post.... Maybe something collided with the end of the table? With the mill bolted down.... No sign of damage on the leadscrew support brackets?

No problem at all. I'm grateful to you for raising this as it led to me discovering the issue with the reduction of travel on my machine!

Miles

Edited By Miles Hellon on 03/01/2019 22:31:40

Edited By Miles Hellon on 03/01/2019 22:43:36

Could it have been caused by a massive "dig in" by someone not understanding the meaning of Light vertical milling machine

On both my milling machine and lathe I have the belts set so they slip rather than stall the motor.

Hi Ian,

Mine is a metric machine. The leadscrews are 19mm dia. x 5mm pitch.

Miles

One hell of a dig in to do that much damage! I know it's a light vertical, but I've had some serious work out of mine table travel notwithstanding. So I guess we'll never know.

So do please keep the updates a-coming, it's always interesting to see how other folks are getting on with machinery you recognise.

My best regards to you both

Simon

Regarding a source for leadscrew nuts **LINK**

Yes mine is a metric machine as well X , Y and knee (quill is imperial) I have a DRO fitted so I very rarely look at the dials. I've seen that seller on ebay his nuts are brass if I did replace mine I would prefer them to be bronze.

When you remove yours Simon I would be interested to see a photo of it, If its just a threaded cylinder held in the casting with grub screws (like mine) or like the E type with a spigot.

Any way good luck with your repair.

Edited By ian j on 04/01/2019 10:28:25

Tonight's update:

Pulled the half nut out of the casting. It was a moderate press fit, came out with a bit of help from a piece of M12 studding. Could have used 1/2 whit, but it is a metric machine....

And here it is fitted in it's proper position.

There, that was an easy fix (if only).

Set up and machining tomorrow, after I've got the wood burner going well.

Rgds to all

While it's in your hand Simon can you confirm it's dimensions as 1 1/4" os diam by 2" long.

I know we can only surmise but I wonder if the damage happened when a new nut was been inserted?

Edited By ian j on 04/01/2019 19:27:50

Ian -

Bush measures 1.243 OD (mostly) by 1.960 long overall. Material is visually bronze, not brass it's not yellow its pink. (phosphor bronze?)

I like the suggestion of having broken the casting by over-enthusiastic bush fitting, that's a simpler and more plausible suggestion than somehow it fell over leaving no other visible marks. The only thing is, that bush is a slack sloppy fit in the remnant of the proper location. The socket left is about 200 degrees of a circle so it's pretty easy to gauge the diameter, and although it's significantly scored it's pretty much round albeit oversize. I wonder if someone failed to realise there was a grubscrew locating the bush axially and radially, wound happily on some kind of extractor and only stopped when it was too late. Ping!

Best rgds Simon

Good afternoon all.

Spent my weekend worshipping the god of swarf, so here is the preparation for my repair to the broken leadscrew mounting casting:

And here it is assembled

xxx

And just to prove that it clears the channel in the bottom of the table casting (if only just):

The orientation of this photo is a bit odd, only so I could get the camera near enough. "Up" is about 10 o'clock.

So bung it all back together and it all fits and lines up and slides and wotnot. X travel now measures 18-3/16, which is a result I'm very pleased with.

Thank you gents for your help in determining that it needed surgery, hope your restoration s equally satisfactory.

Best rgds and a Happy New Year.

Simon

Simon that's  an excellent solution and work, better than original in my opinion. I'm sure you are very happy with the end result not to mention the extra table travel !

Now we need to see how Miles is progressing?

best Regards

ian

Edited By ian j on 06/01/2019 16:22:24

Good work Simon. That looks pretty bombproof!

No progress at all here, I'm afraid. I've been working hard at getting my new workshop ready. That is the priority, at the moment. I've given myself a deadline of the end of Jan.

Any luck with the feednut Ian? Maybe you could ask the guy in Cardiff if he would do one in bronze? There are short lengths of bronze bar available on Ebay. I would order one too, if it makes it more worthwhile. I presume that the cross slide nut is the same dimension? That is the one with excessive back lash on mine...

ATB

Miles

Miles.

You must have read my mind as I did contact the ebay chap.I think he would have been prepared to make one but he must screw cut the thread and then finish with a tap. But he only has a LH 3/4" by 5mm pitch tap.OK for the Y axis but the X is RH.

The Y AXIS nut is not just a cylinder, see photo.

If you join the yahoo Tom Senior group , in the files section there is a file showing how to modify the nut to compensate the back lash..

Ian.

Oh, that's a pity...

I'll check out that file. Thanks for the info.

Miles

I realise that this is an old thread, but I couldn't resist a few comments.

Regarding the X axis nut being in the wrong position, I would have first tried turning the leadscrew the other way round, so the handle was on the left. I removed one of these nuts the other day and came close to breaking the casting as yours was. I removed the grubscrew and started drifting the nut out, to no avail. Looking closer and cleaning the grease off of the outer end, a round mark appeared. It turned out to be an axial threaded hole centred on the bronze/cast iron joint line with a 2BA x 1/2" long grubscrew in it.

I have to make a 3/4" X 5 acme nut, and have ordered a tap from Tracey Tools, they also sell trapezoidal taps.