Union (Boxford) PD4 Pillar Drill

Laying a a scrapheap, I chanced upon a Union PD4 floor standing pillar drill. Remarking that it looked too good to go to scrap I was told 'yours if you want it'. Needless to say I did not need telling twice! I dismantled it to transport home and have conducted, thus far, a very cursory inspection and checked the details on lathes.co.uk. The machine is reasonably complete, the electrics have been butchered (possibly when converted from 3-phase) and has remarkably little 'drill rash' on the table which makes me think it has not hard a hard life or the main fault I found precluded it being used much in its former life and worthy of a little restoration work. It appears to be the two-speed model, at least that is indicated on the speed information plate, and the fault seems to be that the spindle will engage with the pulley wheel only when the gear lever is in one position which makes me think there is stripped gear somewhere in the head.

So, the question is this: does anyone have any information on this machine, other than what is on the 'lathes' site and an exploded parts diagram they could let me have? I would, of course, cover all photocopying and postage costs if the information is not in an electronic format. And, has anyone dealt with type of fault in this model of drill, if so what was their solution?

I am guessing that if you have a gear lever for high and low ratio's, then it will be PD8 like mine.

Are you aware that Boxford have some exploded views and spares lists on their website, there is one showing a fibre gear which could be a contender for having some stripped teeth.

http://www.boxford-software.com/spares/menudrill.html

http://www.boxford-software.com/spares/DrillFibreGear.html

Phil

Phil,

That's is very helpful, thank you. I am in almost total ignorance at the moment as to this machine's inner workings and how to go about resurrecting it, but everything yields to analysis and observation I have found. I will check out the information you have supplied, thanks again.

Phil,

The penny has just dropped. PD4 = 4 speed, PD8 = 8 speed, i.e. geared. Sorry, I haven't been stupid very long!

Just an aside, sorry, but that Boxford site always throws up a Trojan warning on my PC - I can explicitly allow access, but I just wonder what exactly it thinks is the problem?

Rob

.

No idea, Rob … my iPad seems quite content with it.

Just in case Chris feels uncomfortable about it … I have grabbed the illustration of the fibre gear assembly.

MichaelG.

.

Edited By Michael Gilligan on 06/01/2023 18:15:48

I am very grateful for the help and advice offered, thus far. Having found the Tufnol gear spindle (Part PD4-137) lying in the cavity of the drill head I am now convinced the problem is either a stripped or missing gear or someone has had this assembly apart before and failed to put it back together properly. It seems that very little detail was ever published about these machines and probably no complete exploded parts diagram ever existed. So, before I 'poke and hope' has anyone ever stripped one of the machine's heads and did they take any photographs or make any sketches that they could give me sight of?

You say the spindle and gear assembly were lying loose in the head cavity. Surely that is the cause of your problem, not a stripped gear. Put it back together again and all should be well, I don't see the difficulty really, it can't be that difficult to see where it should go having found it.

Regards Brian

Regrettably, I have not found the whole assembly as indicated in the diagram, merely what looks like to be the gear spindle. There is nothing obvious as to how to the remove the main spindle and dismantle any internal assembly. I have no fear as to what may lay inside, but I thought it may save some time and trouble if someone could 'prime' me as what to expect and an exploded diagram or photograph of the whole assembly would make everything obvious. It seems, as far as I can currently ascertain, that no such diagram was ever published by the manufacturer but I stand to be corrected and live in hope.

My apologies, I read what I expected to see! If you are not able to get any information I may be able to help you by making a new fibre gear, but I will need the gear spindle to fit it to and a tooth count and diameter for the drive pinion to establish the DP value. I imagine it will be 14.5 degree pressure angle, based on the period these drills were made. You might be able to figure out the gear thickness, but as a first guess it looks pretty close to the shaft diameter.

A centre to centre distance between pinion shaft and fibre gear shaft will help to establish the tooth count of the absent fibre gear. From the picture Michael Gilligan thoughtfully posted it looks to be 40T or more probably 41T

Regards Brian

Brian,

Thank you for your kind offer of making a gear for me but I can make a new gear myself if necessary, that is not an issue. My 'problem' is that, from observation, there is no obvious way into the mechanism from outside of the drilling-head casting so I am assuming that when I start to 'excavate' the complete spindle/quill will come out of the head, either from the top or bottom, and that the gear change will be some sort of in-line sun and planet arrangement, but I really have no idea at this stage. I have the machine in pieces for a good cosmetic cleaning at the moment, replacing missing plastic knobs etc., and I think I should re-assemble the drill-head on to the pillar to work on it. I just thought that if I could obtain a photo or a sketch of the complete spindle/quill, because the information on lathes.co.uk appears to indicate that no 'official' exploded diagram was ever published, it would make things a bit more obvious. The Boxford parts drawings are useful but unfortunately are not telling the whole story. Having found the gear spindle lying in the head casting where the start-stop buttons and NVR once lived I am assuming that at some time in the past the spindle drive has failed and somebody has done a 'bodge' job on it to get it up and running again. It was usable with the gear lever in the upward position when I obtained the machine but obviously only four speeds were available from the stepped pulley and I like things to be 'right'.

Hello Chris,

Well, at least we have kept the topic open and someone else may spot the exchanges who is able to help you in your quest for information.

I hope it all goes well for you with a happy outcome

Regards Brian

Chris, if you post a few photos of what you have, someone may be able to suggest how to proceed, or at least try.

Hopper,

Yes, I will try to post some photo's as soon as I get the drill-head back on the pillar which I think will make dis-assembly easier. At the moment I am still cleaning off 50years of dirt and rust and replacing some ugly and not very spherical steel ball handles which someone has either brazed or glued on to the clamp screws. The easy jobs first!

I have taken some photographs of the drill-head I have titled them and put a note on them to try to explain my difficulty. At this stage I am still in complete ignorance as to how to remove the quill/spindle as there does not appear to be any other way than to withdraw it from either the top or bottom of the casting. Whether this will just slide out when I have found a way of removing the pinion shaft or whether it will need to be forced out by some means remains to be seen. I am assuming that the slot in the front of the head and the provision of what appear to be two clamping bolts is to hold assembly in position, but one is missing and the other is slack at the moment with no apparent movement of the spindle, possibly because the pinion is still engaged in the rack or the bearings are held tight in the head elsewhere. There is a bushed hole parallel to the spindle in the upper part of the casting with no apparent function, so if anyone can tell me what it is for I would appreciate the advice as I have no idea at this stage.

The gear change appears to be effected by sliding an inner sleeve up or down with an eccentric a spigot on the end of the gear-change lever which seems to confirm my initial thought that the gear-change is effected by some sort of epicyclic arrangement within the spindle, but again I have no idea what is in there at this stage. The component in the same photograph as the gear-change lever was found loose in the head casting and appears to the Tufnol gear spindle shown in the Boxford diagram.

I stand to be corrected, contradicted and educated on all this by anyone who can provide any guidance or suggestions as to how to go about stripping this head down for repair because, unless I am missing something obvious, there appears to be no way into the mechanism to me at the moment. Clearly, there will be a way of getting in there and all will be revealed, it's just that I don't know what it is at the moment and would appreciate some advice before I go attacking it with all guns blazing, if you know what I mean.

Edited By Chris Crew on 16/01/2023 13:45:02

Edited By Chris Crew on 16/01/2023 13:48:54

Chris,

I don't know this model but I am pretty sure extracting the spindle/quill assembly will be very similar to what is done on other makes of drill.

You need to extract the pinion shaft that racks that part up and down. There will probably be a clock spring attached to the shaft on the left hand side as you look at the machine, fitted into a housing of some kind that can be wound up and then locked to vary the degree of spring return as you crank the operating capstan on the right hand side. Often there is then nothing to prevent the innards from dropping out of the bottom of the drill housing, so be prepared for that. At the top end the spindle will have a splined section that engages with internally cut splined in the drive pulley

Once you have that out you may be able to see how the speed shift gearing works. The pinch bolts, you are correct, one is missing, that close up the central split in the casting may either adjust the grip on the quill to take out any slop or act as a locking feature

Refitting is a case of inserting the quill again, making sure the pulley splines engage and holding it in place with a prop of some sort so that you can refit the pinion shaft. You will need to work on the spring return to reset that to a tension that will raise the spindle again without it being too enthusiastic

I hope these notes help   Brian

I should have added that the short shaft with a pin in your last picture engages the pin into the slot at the bottom of the hole it is next to raise and lowered that slug to alter the gearing. Beyond that you may well find out what it does when it operated once you have an internal view  Brian 

Edited By Brian Wood on 16/01/2023 17:25:11

It turns out that my assumption was completely incorrect. The gear change is not effected by some in-line epicyclic arrangement on the spindle. What I took to be a blanking plate on the top of the head casting was actually concealing the Tufnol gear assembly, minus its shaft which had dropped out and that which I found in the lower casting void. This shaft is clearly meant to run in the two bushes parallel to the main spindle, which is obvious to me now, and had originally been retained by two circlips judging by the grooves at each end of the shaft. The Tufnol gear and its accompanying steel gear on the same shaft act as sort of lathe back-gear arrangement. When the top speeds are in use the drive from the pulley is direct by the engagement of dogs on the split spindle with the steel gear being dis-engaged. When the lower speed is in use the gear assembly on the on the main spindle is moved down, disengaging the dogs and engaging a larger gear mounted on the gear-change sleeve with the smaller steel gear on the Tufnol gear shaft, which I should now really call a layshaft. The driving key for this larger gear was displaced and gear was just running free around its spigot. So there were actually two faults with the mechanism both of which are now just simple repair jobs.

Which fault caused the drive failure first is hard to say, the layshaft bushes in the casting appear to be quite worn so will need replacing, although the gears rotate freely on the layshaft which could actually stay stationary. I don't know what the original intention would have been. The large gear is running a little too free on its spigot so I will have to possibly bore it out a little and fit a bush so it doesn't rattle its key out again. But in any event I will have a machine which will well outlast me, I think. I will take some more photographs of the arrangement in case someone else encounters the same, or a similar fault, with this type of machine.

Edited By Chris Crew on 17/01/2023 13:49:41

A good outcome by the sound of it, nothing too difficult to source or repair. A good find for you at the dump! You should get a lot of satisfactory use from it

Brian

Well, I have got the drill re-assembled for a test run but then I noticed a discrepancy. The machine, as recovered from the scrapheap has 3-step pulleys on both the motor and drill head, not the 4-step as indicated on the speed plate. I guess that makes it either a PD3 or PD6? So, may I ask if anyone has the PD8 model could they kindly measure the diameters of the pulleys on both the motor and drill head end and let me know so that I can try and source the correct pulleys from somewhere and if anyone can tell me where these pulleys may be available (I don't expect them to be OEM parts), so much the better.