Restoration and modifications to a Tom Senior light vertical mill

[Miles HellonParticipant @mileshellon]

I've just sketched out my initial thoughts:

[Miles HellonParticipant @mileshellon]

The idea is to keep everything within the original top cover, which will have a couple of slots added to access the new controls.

[Miles HellonParticipant @mileshellon]

Maybe something like this?

[Simon Williams 3Participant @simonwilliams3]

Hello one and all, and best wishes for a Happy New Year.

I've got one of these little beauties, and I have moved the ram probably twice in the last ten or fifteen years. But it all depends on the size of work you want to get at.

A more significant restriction to me is that the X leadscrew isn't fully threaded. As a consequence there is an area about 12 inches wide at the right hand side of the table I can't traverse under the head. Is this the case with yours?

I've been considering remaking the lead screw to improve this, but it's a lot of work and I haven't yet summoned up the courage to cut my first ever square thread. And it's metric, my lathe has got an imperial leadscrew.

However I'm really curious to know how many speeds your mill has got. Tony Griffiths' archive says these had 5 later six speeds, I reckon mine is a fairly late model but it only has four speeds selectable by moving the drive belt within the head.

The modification I did carry out after a lot of thought was to change the bearing supporting the driven pulley atop the quill to needle rollers. The original bronze bearing was pretty poorly so I needed to do something with it and decided to go for gold. There are pictures in my album of the results.

All the best Simon

[Miles HellonParticipant @mileshellon]

Hi Simon,

Pic of the RH end of my leadscrew below. It's threaded up to 150mm from the collar. I get 15" of travel, which is the spec. given in the earliest catalogue for the 25" table…. The later machines, like ours, with the 28" table should have 17" of travel…. Hmmmm…

Mine has four speeds.

It's interesting that some of the catalogues give needle roller bearings for the tail end of the S head spindle and some give Bronze bearings, and not in the order you'd expect…

What is the serial No. on yours? Mine is V3967

From the table posted on the Yahoo group:

1975 ……………….. 3627

1976 ……………….. 3727

1977 ……………….. 3806

1978 ……………….. 3896

1979 ……………….. 4008

1980 ……………….. 4113

1981 ……………….. 4165

1982 ……………….. 4238

1983 ……………….. 4290

[Simon Williams 3Participant @simonwilliams3]

Hi Miles, well I can confirm that mine has the 28 inch table, and the view of the screw looks exactly the same. But where is the serial number?

Best rgds Simon

[Miles HellonParticipant @mileshellon]

Hi Simon,

Serial number should be stamped into the front face of the slideway at the top right of the main column.

So, you have 15" of travel?

Limit of travel at the RH end is the leadscrew support casting hitting the face of the lower section of the slideway. The first rib of the casting is 2.5" from the face. Not sure what's limiting travel at the LH end yet….

Kind regards,

Miles

[Miles HellonParticipant @mileshellon]

Ha! Loosening the screws on the LH leadscrew support and lifting it as far as the screw hole allows gives just enough clearance for it to pass the face of the lower section. This gains the lost 2"!

As far as gaining more movement at the RH end, the face of the leadscrew nut is 225mm in. So, lack of thread can't be the problem. The leadscrew collar would hit the rib at 30mm beyond the present limit…. Anyway, there is 30mm to be gained there with more radical action…..

Kind regards,

Miles

Edited By Miles Hellon on 03/01/2019 16:02:25

Edited By Miles Hellon on 03/01/2019 16:04:23

[ianjParticipant @ians]

Just measured the table travel, on my 1975 machine fitted with a 28" table, as 17.3"

Limit of travel at the LH end is the leadscrew support casting hitting the feednut/housing

Ian

Edited By ian j on 03/01/2019 16:09:16

[Miles HellonParticipant @mileshellon]

Thanks Ian.

Is your limit at the RH end when the leadscrew support casting hits the face of the lower section?

Kind regards,

Miles

[Simon Williams 3Participant @simonwilliams3]

Hello Miles, thanks for that. I've completely changed my theory that mine is a late model, as the serial number is V3485, which puts it off the scale into prehistory. I'd assumed given the 28 inch table that it was later rather than earlier, but who knows, maybe that isn't the original table!

The other revelation is that the table movement is 13 inches (12-7/8 actually) not 15, let alone any more. The stop going towards the right is the leadscrew tail bracket contacting the knee, the stop going left is the leadscrew running out of thread. Travel going right isn't the issue for me, the cutter is just about over the left end of the table by the time the movement stops anyway, but I don't understand why the right hand area of the table is out of limits, for the sake of cutting a thread the full length of the lead screw.. But your leadscrew appears to be the same so I'm assuming that's how Mr Senior meant it to be. Odd or what!

Oh, and I tried your trick with lifting the left hand supporting bracket, it's already high enough it isn't the problem as it passes the first recess anyway.

Best rgds Simon

[Miles HellonParticipant @mileshellon]

Hi Simon,

I just posted an extract from the table so:

1970 ……………….. 3033

1971 ……………….. 3131

1972 ……………….. 3240

1973 ……………….. 3363

1974 ……………….. 3492

So, your leadnut is in a different position than on Ian's and mine then? Perhaps, as you said, the table has been replaced?

Kind regards,

Miles

[Simon Williams 3Participant @simonwilliams3]

Hi again Miles, thanks for the additional info. My leadnut certainly looks like it belongs where it is! But there is certainly something odd going on here., and I'm starting to wonder if the thing to do is to remove the table and take a photo of the knee. I still think the basic problem is that the leadscrew should be threaded for its full length, which is where I started. and maybe that's something to do with fitting the long table on the original design of knee. With my knees (now there's another story) sorry knee the lead nut is inside the right hand side of the casting by 2-1/2 inches. I'm guessing that the knee for the longer table has the nut well to the left to give the extra travel and I'm beginning to see this as an easier mod' to do than making a complete new lead screw. I feel a project coming on.

If you do take yours off during the course of your refurb' please take a picture and maybe we can compare notes.

Best rgds and thanks again for your help.

Simon

[Miles HellonParticipant @mileshellon]

Hi Simon,

Right, that explains it. On mine, the lead nut is almost 9 inches inside the righthand side.

It does seem like there's a mismatch somewhere……

Sure, I'll take lots of pics when I take things apart.

Regards

Miles

[ianjParticipant @ians]

Yes Miles the limit at the RH end is when the leadscrew support casting hits the face of the lower section.

First photo shows this while the second photo shows the table approaching.

 

 

 

 

 

Simon. The feedscrew nut on mine is as you think, to the left,The photo below shows the feed screw casting coming into contact with it. I thought I had photo's of the table removed, but no!

 I can take a photo tomorrow if you like as it's only a matter of taking the feed screw support casting off and winding the feed screw out and pulling the table to the right far enough to show the feed nut.

 

 

 

Edited By ian j on 03/01/2019 18:21:23

Edited By ian j on 03/01/2019 18:30:23

[Miles HellonParticipant @mileshellon]

Thanks a lot Ian.

I can confirm that, after tweaking the LH support bracket position to clear the face of the lower section, I've now got 16-13/16 inches of travel. Close enough!

Miles

[Simon Williams 3Participant @simonwilliams3]

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

[Simon Williams 3Participant @simonwilliams3]

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

[ianjParticipant @ians]

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

[Simon Williams 3Participant @simonwilliams3]

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

[Miles HellonParticipant @mileshellon]

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

[Miles HellonParticipant @mileshellon]

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

[ianjParticipant @ians]

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.

[Miles HellonParticipant @mileshellon]

Posted by ian j on 03/01/2019 21:56:27:

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

Hi Ian,

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

Miles

[Simon Williams 3Participant @simonwilliams3]

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

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