Bore Reducer

HI all,

I have recently purchased a Fobco star and am giving it a clean and light restorations. **LINK**

On inspection I noticed the motor pulley wasnt spinning centrally and on removing found it had a 1/2 inch motor shaft and a 5/8 pully with a home made aluminium adapter which is at least 1mm too small.

I found the below on ebay, but its in the US and seems a little steep to pay £20

**LINK**

Any suggestions on where I could get a similar product?

Thanks

James

In the US our big box home improvement stores and many hardware stores carry them. They probably will not have the cross hole. You might try similar sources in the UK. Another lead would be vendors selling power transmission components.

My tidy brain finds reducers like that a bodge anyway (no criticism of you, you bought it that way), why not just swop the pulley for one with the correct bore, such as below?

http://www.ebay.co.uk/itm/172382644885?_trksid=p2055119.m1438.l2649&var=471209915903&ssPageName=STRK%3AMEBIDX%3AIT

Note: I know that is 5/8 and you want 1/2", and you may not want the same diameter/number of pulleys, it just happened to be the one I selected, and they will bore you a blank to 1/2" of the size pulley block you choose.

In a week of what seems to be posting coincidences on here, I bought a Progress no 12 drill off the bay yesterday, and I have to replace both pulleys on that, so came across that supplier last evening!

Edited By David Standing 1 on 08/11/2016 16:49:07

Edited By David Standing 1 on 08/11/2016 16:51:04

Hello James,

​If you have a lathe or access to one, it would be much more satisfactory to make your own and get a truly snug, centralised fitting. Slit it longitudinally with a hacksaw and fit it so that the grub screw in the pulley can squeeze it closed across the slit to get a really good grip on the motor shaft.

​Failing that, I'll knock one up for you if you will tell me the length you need down the pulley and post it down to you.

Regards
Brian.

Thanks all for the replies.

I think I would change the old motor before the pulley as its a nice heavy cast iron one and I would like to keep the drill as original as possible, whereas the motor is an aftermarket one and looks to be quite a few years old.

No lathe Im afraid - I have ordered the tubing below. The spindle is 50mm and so 200mm should give me the opportunity to make a couple of mistakes.

**LINK**

it is 1/2 in diameter (which I have just thought after ordering I hope it means internal) with 1.6mm walls which would give me 15.9. 5/8 equals 15.875mm and so I hope I can get it to work.

Will need to cut the slot. The motor spindle is ground flat on one side and so would a hole be advisable?

Thanks

James

Hello James,

​I rather fear you have ordered 1/2 inch O/D tubing, the O/D is usually quoted as the reference dimension.

​A hole, presumably for the grub screw, will not be as secure as the collapsing sleeve I described. I inherited just such a fitting on my horizontal mill on purchase, it was a constant pain with the screw working loose to leave the pulley rattling until I changed it. The slot should be aligned with the flat on the motor shaft in this case.

​My offer still stands as I don't think you can expect correct sizing without lathe adjustment. In any case, a steel sleeve will be much more durable. Send me a PM with your address if you want to take it up and make a contribution to the poppy fund instead of payment.

​Regards Brian

As Brian says - with tube, diameter is normally external, bore is internal.

Also as he says, if the sleeve isn't near on an inteference fit (on both pulley and shaft), the grub screw (which should bear on the sleeve, as Brian says again, not through a hole to the shaft) will push the sleeve to one side, and put the pulley out of balance, inevitably causing vibration.

Edited By David Standing 1 on 08/11/2016 18:09:43

Edited By David Standing 1 on 08/11/2016 18:12:13

do not get rid of the Fobco excellent cast iron pulleys,they really grip the belts and run true and last for years,mine are fifty years and still running like they were new.

And to add, if you are going to change the motor, I would get that first, and make the sleeve to fit the new motor shaft/pulley bore. Don't assume if a motor is advertised with a 1/2" shaft, that is exactly what it will have!

This reminds me of a Hilka polisher I bought off the bay a couple of years ago.

It is based on a double ended bench grinder, and you take the grinding wheels of and slip an adaptor on the shaft with stepped tapered ends to take the polishing wheels.

The adaptor is secured with a grub screw, but the adaptor isn't an inteference fit, so the grub screw pushes it to one side. When you have two polishing mops turning at near on 3000rpm, it literally violently throws itself off the bench, it is so out of balance. I'm not suggesting you will have the same problem, but you will get my point, I am sure.

Ironically your nice Fobco cast iron pulleys will exaggerate any out of centre malarkey, as their extra mass over lightweight alloy ones will exacerbate any imbalance.

Totally agree with the advice to turn one's own, close fitting sleeve. You can measure the shaft and pulley bore and so turn the sleeve to be really snug fit to both. Once slit, the grub screw will ensure a good grip, and then you are in business. It is likely that the cast iron pulleys will last longer than contemporary light alloy ones., and will maintain the "original" appearance, as well as behaviour. (Current pulleys may well be metric, and will still need boring or sleeving to fit the motor shaft, so you will have spent money to be doing what you need to do with what you have at present)

Howard

Pipe is specified by bore, tubing by O/D ... most of the time!

Neil

So when exactly does a pipe become a tube?

Thanks all for the responses

Sounds like the tubing/pipe will be assigned to the "it will be useful one day" cupboard.

Many thanks Brian for the kind offer, I will PM you. I assume I will need more accurate measurements of the shafts and internal dims of the pulley rather then a best guess from a steel rule?

Im happy to purchase some more accurate measuring equipment. I have some spring calipers, but would assume I need a micrometer or vernier calipers? This company is 10 min from work and seem reasonable on price so could pop their at lunch - **LINK**

The drill was working well on purchase, but the weight of the thing and it being on the lowest speed is probably why. Will keep the existing motor for now as still working and seems quiet, but will look to:

• upgrade the switch (unfortunately it doesnt seem you can buy the original switch any more)
• Redo the wiring
• remount the switch near to the original location, the current set up is a little Heath Robinson, and get in the way of some the the drills functions

Hello James,

​Motor shaft and pulley bore sizes are pretty well standardized so your ruler measurements are probably correct, but to make this to size as the sleeve needs to be, better measurements are needed really.

​I bought my Moore and Wright digital calipers from Allendale at one of the Harrogate exhibitions some 4 years ago, they cost me £25 at the time and I have had excellent service and reliability from them, so as your link happens to be for the same company I would endorse your choice. I think they have an offer on M&W at the moment as well.

​I would rewire the machine and fit a proper no-volt release DOL starter switch to it while doing so. If you choose the rating appropriately, its operating range might well encompass an upgrade of motor for the future. I have an old 1/2 inch chuck capacity New Progress bench drill which will do all I ask of it using a 1/2 HP motor

Regards Brian

​

​

Edited By Brian Wood on 09/11/2016 10:04:24

It already is a tube, they are synonymous. 

Michael W

Edited By Michael Walters on 09/11/2016 11:10:38

Thanks Brian,

I now have this new piece of kit **LINK**

I will take the measurements tonight (new baby permitting) and PM you.

The plan is to fit a NVR switch as suggested. Need to work out which one would be most suitable for function, looks and connectivity.

Hello James,

​I don't think you will be disappointed with it, the next one down the line is Mitutoyo at considerably more cost.

I look forward to your PM, Don't forget an address to post it to you

Regards
Brian

In my interpretation, a tube is normally structural in some way, and not intended to carry any substance.

A pipe carries a substance - liquid, gas, air etc.

They are identical when they are a piece of pipe/tube of identical dimensions before they are put into use, they change definition according to their end use.

After I said the sleeves are easy to find, I had a difficult time finding them. Search on e-bay fr shaft adapter.

http://www.ebay.com/sch/Shaft-Adapters-Bore-Reducers/181781/i.html?_nkw=reducing+sleeves

So i guess a tube of paint/toothpaste/gel/smarties is just using the term out of context? The word tubular describes a shape, i.e tube-like it doesn't covey a purpose. A pipe can be described to be tubular for example. Therefore they must be one and the same thing.

This is just like asking when a painting becomes a drawing. You're essentially doing the same thing with both, just using different mediums but they could be described as either. E.g surely an ink blot "drawing" has brush strokes painted onto it? Or Lucian Freud's life "drawings" are actually paintings? The only reasonable conclusion is they can be both.  

Michael W

Edited By Michael Walters on 10/11/2016 01:10:05