pulley problem for electric motor for grinder.

Hi,

The V belt pulley I need to fit to the electric motor for my grinding machine it the type which has a cone in the bore with an adaptor to fit various motor shafts.

This is tightened up with a small grub allen screw, which has vanished off the bench and I can't find it.

I need to know the thread type. At first I thought it was 1/4'' , but that is a fraction too large . Anyone had similar dealings with these cone adaptors and might know thread type?

Mike.

Assuming you refer to taperlock pulley hubs, the ones on bearingboys.co.uk site are 1/4 inch bsw or 3/8 inch bsw.

I've got one out in the workshop, I think. I'll have a measure up after lunch, unless someone beats me to it.

John

Taperlock, if not 1/4 then the obvious one is 6mm. Noel.

Mike,

Just dug out my hub ( a Drive-flex 1210-20 ) and there were two grub screws in with it. One was 0.370" OD x 15 tpi @ 55°, the other, maybe from a smaller hub, but still 0.350" x 32 tpi, also 55°. So it looks likely mine are 3/8". 6mm does look your better bet, as Noel says. Sorry not to be more help.

John

Threads are BSW and the size depends on the taper lock number, they go from 1/4 in 1008 to 7/8 in 5040.

Hi, if it is a Taper-Lock and the shaft is metric, the screws a likely to be metric thread, imperial Taper-Lock ones are imperial thread, but whichever they are, the ends opposite the hex-key end are always slightly domed as in the photo below, if you use any other shape, it is possible that you won't get the taper to lock correctly and they may very well come loose.

P. S. Actually HowardT is correct, just looked at my data book.

Regards Nick.

Edited By Nicholas Farr on 13/05/2022 16:50:14

Be aware that taper locks use a BSW threaded grub screw with a metric socket be they for metric or imperial shaft

Martin

Hi Martin, but many years ago when I first had anything to do with them, they were all imperial hex sockets, but there weren't many metric shafts used then.

Regards Nick.

Something I should have done before writing the post is to check the TPI of the split hole.

Are the two plain holes for locking pins ? Not conversant with these taper locks. By the way, someone had welded the taper lock to the end of the motor shaft . Took some careful grinding to remove it. Luckily most of the welding was the worst I have ever seen and 50% not penetrated. Good thing is motor is saved. Shaft size is 24mm. Looks like I might have to bore out a new pulley if I can't fix this one.

Mike.

The holes without the screws in are for extraction of the hub. Take out the clamping screws and put them into the other holes to jack the hub off the pulley.

Hi, the the removal holes are shown in an above post of mine, if there are two holes for holding the bush in place, there is only one hole opposite the split to remove it, if the bush has three holding screws, there will be two removal above the two holding screws above the split.

Regards Nick.

Edited By Nicholas Farr on 13/05/2022 18:47:54

There is only one holding screw , or was !! The thread TPI is 20. OD of the missing screw must be just under 0.250. A scan of all the thread charts is now a must.

Mike.

Hi Mike, if there is only one screw holding the tapered bush in, I doubt that it is a "Taper Lock" one. The only 20 TPI thread I can find that is slightly smaller than 1/4 is an ASME 14 / 20 which is 0.242" with a core of 0.177"

Regards Nick.

Edited By Nicholas Farr on 14/05/2022 08:37:49

If all else fails and the bush is not hardened, perhaps best plan would be to open out thread to a normal size such as 20 tpi BSW. The machine is rather interesting and pretty old. (50/60/s ) It is a Janita plano grinder, used for resurfacing cylinder heads/engine blocks or manifolds, of which I do a lot of work with.

Mike.

It now seems that the bush was not made to fit down to the 25mm. motor shaft. Obviously why they welded the thing on !! So I now need a plain pulley around 3.750'' approx diameter with a key-way. The key slot on the motor looks to be wider than 1/4'' so that could be a problem.

Mike.

In your earlier post, you state that the motor shaft is 24mmØ, then above, it's grown to 25mm! I can't find a taper lock bush with a diameter of 25mm, but the Dunlop 1610-24 has a bore diameter of 24mm. The keyway in that bush is 8mm wide and 3.3mm deep.

John

With a bit of luck and patience a keyway can be cut in a pulley with a hacksaw and or files. Good Luck. Noel.

Hi John Hinkley, there are 8 25mm and 7 24mm bore Taper Lock bushes to choose from shown on page 129 (section 6) Taper Lock metric bushes

Mike, if your pulley can meet the parameters shown for one of these adapters, you could bore your pulley out to suite one, to fit a new Taper Lock bush with the adapter shown on page 127 (section 6) Adapters

Regards Nick.

Nick,

I only see one 24mm and one 25mm bush on that page. My search was restricted to the Dunlop version.

John

Hi John, looking in the product code columns to the right of bore size 24 you will see one in each column from 1008 to 2017 which makes seven different 24mm bore types and for 25mm you will see one in each column from 1008 to 3020 which makes eight different types. Looking on Bearingboys Dunlop taper bush series, you can find the same sizes.

Regards Nick.