Mick

It may be a stupid question but why a taper pin? I would have thought that unless the taper ran through the clapper box and clapper (tool holder) then the clapper wouldn't be supported properly. If the taper was continuos then any sideways movement in the pin or clapper could cause the clapper to jam on the shaft ; it may be that I am just being naive !

Would it not be better to ream a parallel hole through the box and clapper and fit something like a ground silver steel rod to act as the bearing spindle. This could be secured using screws tapped into the clapper box and fixing against flats on the silver steel rod.

Just a few random thoughts with no experience .

Cheers

Martin

Edited By Martin W on 15/09/2012 15:07:26

Hi there, Mick and Martin,

The use of a taper pin as a pivot isn't without precedent – I have here a WW2 RAF morse key that uses one. You do need to confine the position of the moving part but fibre washers aren't bad for that.

I think I even have some taper pins that might approach the size you specify, Mick. The problem would be finding them!!

Best regards,

Swarf, Mostly!

Mick,you are right ,you should use a tapered pin in the clapper box even if you make one yourself. Colin

one lives and learns, a Taper pin it is then.

Clive

Mac

Thanks for the link, once the reasoning is given it makes sense to use a taper pin. As Clive says 'one lives and learns' and at nearly 70 I am certainly still learning and enjoying it.

Thanks

Martin

I too have learnt something today.

My first thought whan I saw the post was, why would anyone want to use a taper spindle? a conventional parallel spindle looks the obvious solution. Having followed the link I now know that a taper spindle is absolutely normal for a clapper box. I can imagine a variation of the idea using shims to change the axial relationship of the two parts to eliminate the need to have a reamer whan adjustment is required.

I would have though that a clapper box bearing arrangement would not be in the least critical. In use any backlash or play would be taken up the moment the cutter tip hits the job. The clapper box will be pushed back against whatever stop it has, and as long as it hits the same stop every cut, the cutter tip will sit in the same place for every stroke.

My curiosity is aroused now ! if a taper pin in tapered hole makes such a good spindle, why isn't the technique in much more common usage?

Ian

The Taper principle is used in another form Ian, in Tapered Roller bearings !

There was a tale about the Americans shipping wheeled vehs. across the US on flat cars and they ended up with wheel bearing problems. It came down to the balls 'Brinelling' the ball bearing rings in one place from being tied down and the weight and motion damaged the bearings. A change of bearings to taper rollerbearings apparently cured the problem.

Clive

Clive

I was really referring to plain shaft and journal (sleeve) type bearings. Rolling bearings are a completely different animal.

Tapered (and parallel) roller bearings are more resistant to Brinelling than ball type purely because of the larger areas in contact. All types can suffer the same problem though.

Ian

Once you have the pin (and unless you have one, a reamer), you will need to turn a 1/2" length on the small end to take a 5/16"/ 8 mm nut, see my previous entry. Ian S C

Are all taper pins the same taper angle? Surely not. It seems in the past every opportunity to be different was taken.