Meddings Dril Tru - What to do?

I picked up a Meddings Dril Tru (SE: DTB03689 cast: 9373/LT/III) last autumn which has not had one careful owner. A few bits are missing: the knob for the switch, handle for the table, cover for return spring and the threaded bar and nut that holds the belt cover.

Do anyone know the thread for the belt cover bar (a non fitting bolt was jammed into the thread on the base but it has only damaged the first thread)?

The quill, bearings and nearly new chuck all seem good.

The main problem is the spindle pulley and axle. The pulley it is off centre on rotation and also not square on the axle when the square pin is tapped in place, when the pin is not in the is a fair bit of play for the pulley to wiggle on the axle. See pictures.

My experience with spline axels and pulleys is limited and they have all been snug fits. Centred and square on the axel by the fit of the bore, easy drop in of the square pin, tighten set screw(s) - all good. So how bad is this? Replace or refurbish with a bush? Note: I don't have a lathe, a milling machine or the skills to do a refurbish.

It sounds like it could be a 16mm pulley on a 5/8 motor shaft. That would be about 4 thou clearance,

Meddings are still in business and can supply spare parts for some models, I dealt with them at work for spare parts and found them very knowledgeable and helpful, there's a wealth of product experience there.

Well worth a call if you are stuck.

Dave

Edited By Dave Wootton on 01/04/2022 12:33:14

As for the pulley look at fitting a taper lock one, easiest solution without machining the shaft.

WILD guess, but the thread for the belt cover stud might be Imperial, ,BSF or BSW, or maybe UNF(Less likely in my view )

Cannot imagine it being Metric.

By the looks of the shaft, the pulley was fitted without a key, so that it has slipped on the shaft and scored it. This may account for the, now, loose fit.

If you had a lathe, I would have suggested boring out the pulley slightly and making a bush to return the bore to the correct size for the shaft (Once it had been deburred )

This would mean having to recut the keyway, in the bush, probably to coincide with the remains of the keyway in the pulley..

Howard

Hi All, thank you for the replys.

I managed to find a bag of old UNC bolts this weekend and a 3/8 fit nicely, so most likely a 3/8 BSW. Easy to get some threaded bar to fix that.

I also did six measurements on the shaft 22.11/15/17/20/24/29, so that is 7/8'' (which is 22.23mm).

Would it be possible to get a resonable fit with a new pulley on the shaft without machining it?

Jon

The 22.24 and 22.29 dimensions, suggest burrs on a nominal 7/8" shaft.

A pulley with an an accurate 7/8" bore would be a slightly loose fit on a 22.11 mm shaft,

But a grubscrew, bearing on the key may prevent any movement , The 0.005" clearance will ,probably cause the pulley to run slightly eccentric.

Howard

Possible yes as pulley is softer than shaft so more likely to have worn out of round, but not guaranteed.

Is the one on the motor end the same? In bodger's corner I might try stoning the damaged shaft to take off the ridges then swapping them over and if it looked promising then perhaps some stud & bearing fit compound.

Good suggestion Adrian, just checked but the motor shaft is smaller, 5/8''.

I've contacted Meddings, but still to get a price on a new pulley.

Another option could be to get 5 step pulley with a 22 mm bore, which seem available, and then trim the axle and adjust the key to fit.

That shaft doesn't look too bad. If the pulley hole is worn / oversize you may be lucky with a shim made from an aluminium Coke can. My wife has a Meddings drill for sale; the cover bar is threaded 3/8 x 20 BSF.

Whereabouts are you? May have some Meddings spares.

Why would you need to "trim the axle"?

My usual fix in these situations is to turn and bore a piece to fit over the existing shaft. Bored slightly undersized, warmed up and tapped into place. Rock solid and no wobble.

Hi AJAX,

Thanks for your reply. I just had another look at the threaded cover bar hole in the cast base: the upper 8-9mm has brute force 3/8 x 16 (UNC or BSW) 'thread' and the rest in finer, so no doubt you are right that originally it was a full 3/8x20 BSF. I tried with the lock handle which is 3/8x20 BSF but that now fits worse than a 3/8 UNC. And still it came with a M10x1.5 jammed into the first thread....arghhh.

My reason for trimming the axle was to make it fit a new 22mm bore pulley and use the key and set screw to hold it in place.

Meddings are very helpfull, but many parts are not available. The spindle pulley is available at £100.75+VAT+Shipping.

I am in Aldridge, West Midlands.

Hi Jon,

That sounds like a very expensive pulley to me. I would have thought it should be possible to find one elsewhere at a much more reasonable price. Shame those threads have not been looked after.

Ebay has generic step pulleys for 25 quid. So does RDG Tools. Should be able to bore out the hole and even cut the keyway in aluminium in the lathe if you have one. You might have to buy a matching pair of pulleys to get constant belt tension on all steps though?

I would try to repair the pulley - and likely to succeed. I would bore it out if/as necessary, sleeve it - and replace the smallest sheave if necessary.

Doesn’t look to be a too difficult job. Broach might be required, but one would, at least, have a tool for future use.

Looking at the pic, it likely needs another keyway cutting on the shaft.

Hi All, thanks for your replies.

I'm not keen to spend ~£130 on a pulley for this 'pig' of a machine (other threads have been misused and the casting for the depth stop has been knocked off). I have been looking at generic 5 step pulleys online. Amazon and ebay have lots available for type A belts (w 13mm / d 8mm) but none for type SPZ (w 10mm / d 8mm) - the slightly larger version used for imperial Vee or 3V belts.

Needless to say this machine came with a type A belt on the Vee groves.

Does anyone know where to get a generic 5 step SPZ pulley?

This is starting to look like a longer term project to either find a used pulley in good nick or bump into someone that can sleeve the original.....or maybe the little common sense voice in my head telling me to sell the good bits and use the stand for the bench grinder wins.

Keep the stand, Sell the drill for spares, and buy another drill t;o go on the stand.

Sad end for a drill. The body is now a heavy and sturdy base for my work light (came on a lousy tripod that was always in the way and easily got knocked over). Stand will be for the bench grinder and other useable parts are being sold.

Thanks for your replies.

Could you not just use the generic Type A pulley/s? Some are so cheap you could convert both pulleys to A belt and still come out ahead. Also, an A belt will run in an SPZ groove, as I do on the motor to countershaft pulleys on my Myford. Seems a shame to trash a good old machine for such a minor issue.