Taper pins and taper reamers?

Ian_C

Western Thunderer
Thinking of having a go at telescopic split axles in 7mm, so 3/16" diameter. Been looking at taper pins to fix gauge and quartering. There seem to be 'engineering' taper pins to DIN and BS that go down to about 1/16" in size, and you can buy specific taper reamers to match. Below that in size there are hordes of horological taper pins. They don't seem to have any info on taper and I've found no matching reamers. So...are there standards for horological taper pins? How do clock folk make the matching tapered holes?
 

Neill

Active Member
I'd suggest using a small cutting broach, you can get them from Squires and others. They come in small sizes and are tapered. I don't know whether you can get matching taper reamers.
 

richard carr

Western Thunderer
Ian

for 3/16th axles I would use one of the engineering taper reamers and matching pins. I use an imperial 1/16th of an inch taper reamer that has a 1 in 48 taper on it. If you do a search on the web you should be able to find the matching pins, you might need to buy a lifetimes supply for say £50 but it will last you a lifetime, I think I have about 5 lifetimes supply at the moment.
There is a metric equivalent taper reamer that has a 1 in 50 taper.

They are not cheap but you will only need to buy it once.

Richard
 

Ian@StEnochs

Western Thunderer
Before I obtained a tapered reamer I had some success using just a piece of brass wire as the pin. I drilled the hole through the axles with a 0.9mm drill and tapered the end of the wire until it slid through. A tap with a hammer while the axle was supported on a hollow stake fixed the wire in place but still easily removed by a tap from the other side. The two locos so treated are still running.

As to supply of a proper 1 in 48 taper reamer, new ones are very expensive, try 2nd hand tool stalls at traction engine or tractor shows. Last time I was rooting around I found a box of assorted reamers, including tapered ones, most in quite useable shape for £7 after a wee bit if a haggle! I also picked up a bundle of 3 pin chucks for another £5.

Ian.
 

Martin Shaw

Western Thunderer
Ian
Tracy Tools have both metric and imperial taper reamers. The smallest metric is 1.5mm and cost £20, the smallest imperial is 1/16" and costs £10.
Martin
 

Locomodels

Western Thunderer
As you only have to buy this item once, at such a good price, I would snap one up.
Keep it well greased/oiled as rust will kill it.

Paul.
 

Ian@StEnochs

Western Thunderer
Ian
Tracy Tools have both metric and imperial taper reamers. The smallest metric is 1.5mm and cost £20, the smallest imperial is 1/16" and costs £10.
Martin

Thanks Martin.

I had forgotten about Tracy Tools. I used them a lot when I was involved in larger scale model engineering. I still have my set of ME taps and dies which I got from them in the early 80s when they were considerably less expensive than a similar set from one of major model engineering suppliers.

Ian.
 
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