Denford Software & Machines

Hi. Has anybody taken a Senior Quill Head apart? Mine needs a new top bearing but I cannot find any way of removing the spindle pulley. There are 2 socket grub screws in the same hole in the pulley, but removing them makes no difference. The pulley stays put! It does jiggle up and down about 1mm with a solid clunk at each end of the jiggle as if it is a key hitting each end of a keyway. Anyone got any ideas?

Have no personal experience but, if its a "Senior" and not a "Senior 3C", you may glean something from the drawings in the Senior Manual which Denford have kindly placed in the download section.

Would be interested how you get on - haven't had to service mine yet (a Senior 3C).

Dave

Hi Dave. I've got a manual but the drawings are 'primative' and don't give clear detail. Ideally I need to look at the GA but Denford tell me it would take weeks to find it in the archives. My mill is a Denford Senior Universal. The Quill head is the one that clamps to the vertical dovetail. If I find out how to do it I'll let you know. Regards, Bob.

Can you post a pic of the head so that we know just what you need - I have drawings numbers / copies for various Denford Senior bits, but the machine naming seemed to be a bit random around that period.

Andy

Hi Andy.
Hope these help. Any assistance will be greatfully received. If you have any relevant drawings I will gladly pay for copies and any associoated costs.
Kind regards, Bob.

Andy B wrote:Can you post a pic of the head so that we know just what you need - I have drawings numbers / copies for various Denford Senior bits, but the machine naming seemed to be a bit random around that period.

Andy

Looks like a standard Senior quill head (just wanted to check as the base machine is a Denford Senior) - I replaced the bearings on mine a few months back.
The cross-section shown in the manual is misleading, as it shows the later type with double bearings top & bottom on the main spindle, and ball bearings for the pulley spindle.

I expect that inside yours is a single pair of taper roller bearings for the main spindle and a plain bronze bush for the pulley spindle.

What I can't recall off hand is exactly what I had to do to remove that pulley - I'll have a look over the weekend and get back to you.
If you're in the East Midlands, you're welcome to borrow the peg spanners I made to do the job.

I decided to replace both bearings as they are fairly cheap. To fit the lower bearing onto the spindle, I put the spindle in a plastic bag then stuck it in the freezer for an hour or so. Then wrapped the bearing in cooking foil and put it in a moderate oven for about 10 minutes.
The bearing then just dropped straight onto its locating shoulder, and was held fast within 30 seconds or so - no press, mallet, tubes or anything else needed.
All with full domestic approval!!

For many people the next question usually relates to setting the bearing pre-load. My experience (also posted on the Yahoo Tom Senior group) is:
"Without special tools and the designers setting instructions, general wisdom seems to be to rely on the running temperature. I gave my adjuster nut about 1/12th of a turn extra once the axial play was just
removed, then once re-assembled ran it for 5-10 minutes at each speed starting with the slowest. The spindle got warm, but I could comfortably hold my finger inside the taper (when stationary!)."

Andy

Just had a further think...
There is a picture under S-Spindle-1.zip on the Yahoo Tom Senior page - this shows an earlier arrangement than yours (quill lock is a screw on the front, not a split clamp) but shows essentially what you should find inside.

From what I remember now, the pulley is a close fit on its spindle and the grub screws that retain the pulley tend to throw up a burr when they are tightened. Consequently, it is very tight to remove and the pulley bore inevitably gets a bit scored.
When you jiggle the pulley, is the pulley spindle moving with it? If so, I suspect that the 'clunk' you are hearing is the flanged head of the pulley spindle contacting the housing. They seem to be assembled with a fair amount of axial clearance!!
So the first time you remove the pulley, it needs a bit of faith to get a lever as far under the pulley as possible and gently prise it up. Once it is off, you can file a small flat on the spindle so that subsequent burrs when you re-assemble with the grubscrews won't affect any future dismantling.

I wanted to minimise the axial float when re-assembling, and it becomes a bit of a game to hold the pulley spindle up whilst pushing the pulley down - so a small wedge (a thin flat screwdriver) down the main spindle keyway helps to lock the main splindle and pulley spindle together whilst adjusting the pully position.

Andy

Hi Andy. Thats very helpful. Sorry I'm late getting back to you but had to go away unexpectedly. The pulley jiggles on the shaft. I shall take your advice and use a bearing puller for the pulley, and hope like hell that nothing breaks!!
Thanks for your help. I may have to come back to you for more advice if that is OK? Bob.

Andy B wrote:Just had a further think...
There is a picture under S-Spindle-1.zip on the Yahoo Tom Senior page - this shows an earlier arrangement than yours (quill lock is a screw on the front, not a split clamp) but shows essentially what you should find inside.

From what I remember now, the pulley is a close fit on its spindle and the grub screws that retain the pulley tend to throw up a burr when they are tightened. Consequently, it is very tight to remove and the pulley bore inevitably gets a bit scored.
When you jiggle the pulley, is the pulley spindle moving with it? If so, I suspect that the 'clunk' you are hearing is the flanged head of the pulley spindle contacting the housing. They seem to be assembled with a fair amount of axial clearance!!
So the first time you remove the pulley, it needs a bit of faith to get a lever as far under the pulley as possible and gently prise it up. Once it is off, you can file a small flat on the spindle so that subsequent burrs when you re-assemble with the grubscrews won't affect any future dismantling.

I wanted to minimise the axial float when re-assembling, and it becomes a bit of a game to hold the pulley spindle up whilst pushing the pulley down - so a small wedge (a thin flat screwdriver) down the main spindle keyway helps to lock the main splindle and pulley spindle together whilst adjusting the pully position.

Andy

Hi Andy.
Just klicked on the S-Spindle-1.zip and it won't let me do anything because I'm not signed up to Yahoo. Bob

phoenix wrote:Hi Andy. Thats very helpful. Sorry I'm late getting back to you but had to go away unexpectedly. The pulley jiggles on the shaft. I shall take your advice and use a bearing puller for the pulley, and hope like hell that nothing breaks!!
Thanks for your help. I may have to come back to you for more advice if that is OK? Bob.

Andy B wrote:Just had a further think...
There is a picture under S-Spindle-1.zip on the Yahoo Tom Senior page - this shows an earlier arrangement than yours (quill lock is a screw on the front, not a split clamp) but shows essentially what you should find inside.

From what I remember now, the pulley is a close fit on its spindle and the grub screws that retain the pulley tend to throw up a burr when they are tightened. Consequently, it is very tight to remove and the pulley bore inevitably gets a bit scored.
When you jiggle the pulley, is the pulley spindle moving with it? If so, I suspect that the 'clunk' you are hearing is the flanged head of the pulley spindle contacting the housing. They seem to be assembled with a fair amount of axial clearance!!
So the first time you remove the pulley, it needs a bit of faith to get a lever as far under the pulley as possible and gently prise it up. Once it is off, you can file a small flat on the spindle so that subsequent burrs when you re-assemble with the grubscrews won't affect any future dismantling.

I wanted to minimise the axial float when re-assembling, and it becomes a bit of a game to hold the pulley spindle up whilst pushing the pulley down - so a small wedge (a thin flat screwdriver) down the main spindle keyway helps to lock the main splindle and pulley spindle together whilst adjusting the pully position.

Andy

PM me your email address & I'll send you a copy of the drawing.

Andy

P.S. I'd be very wary of using a puller unless you can get it right inder the pulley - the edges break off easily, as I learnt to my cost when I had to remove my motor pulley (the previous owner had used a loctite-type adhesive, which wasn't obvious until I got it off)

Another little bit of advice - don't use too thick an oil when re-assembling the quill - if my machine is cold and not used for a while, the quill locks up and takes some persuasion to free it again the first time it is used again. This is accompanied by a very audible 'whoosh' of air, so there is not much wear in it after 25 years of use!
I must get round to taking it out again, cleaning the 'sticky' oil off, etc.

For completeness I've attached the drawing in question, from the Tom Senior site... hope no-one minds!

Don't Denford own the IP rights for Tom Senior?
So it's yours to do as you wish in terms of publication.....

Don't Denford own the IP rights for Tom Senior?

You'd know better than I would !

Either way, I thought it'd be ok, and it would save anyone else having to create a yahoo account, join the group and wait for approval etc...

btw, that article on DST was interesting - I was just a bit confused about the Harrison connection in the early 50's - ie, what did they take, what did they leave ?
Funnily enough I have just heard a rumour about a 600 Lathes name change....