Certainly some Sherwood products have never been near the forest so you may just be paying for the name.

I use CT90, but 3in1 would be better than dry. CT90 is probably intended for steel pipe threads in plumbing.

The bigger the hole you drill, the larger diameter part of the reamer you will be using and therefore it will be stronger.

So you can measure up your pin and decide which part of it you want to use and drill to the diameter of the smallest part of the pin you wish to contact the hole, allowing a few thou for fitting. So your intuitive mid-point diameter was probably about right. If it works, go with it!

Yes, I have an ancient tin of Trefolex too, sourced from a garage sale, and seems to be an endless supply. Its good stuff for tapping and reaming.

Edited By Hopper on 28/11/2020 06:34:30

Where I was trained it was practice to drive small taper reamers by hand with a tap wrench,and used a similar tallow based lubricant similar to Trefolex, step drilling does help on all sizes of taper reamers,After apprenticeship days I did not use taper reamers until the 1970s when I started restoring stationary engines,I now have a collection of reamers,a mixture of straight and spiral flutes,I tend to use spiral flute type in the drilling machine as it clears the swarf easier,care has to be taken when reaming a hole through a cast iron boss fitted to a steel shaft,the mix of swarf tends to jam the reamer,another good lubricant is liquid Rocol.

I've always used taper reamers by hand and dry, which means no mess to clean up. I set the hole size to drill by measuring the diameter of the pin a bit up from the small end where I think it will actually exit the hole. i agree that the key is light axial pressure and frequent withdrawals. Towards the end the reamer is cutting over nearly the full length. One can "feel" the reamer cutting or shaving really. The steel swarf I got was very fine,almost like a powder. Don't forget to check with the pin at frequent intervals. It's easy to make a turn or two too many with the result that the pin will stick through too far. If anything stop early. In use the pin will be tapped home and so will go in further than quick check by hand would suggest.

Andrew

I've been watching this thread with some interest.

I have some 'clock' taper pins (1 – 1.5mm) in my stock box which I think would be quite useful in some of my smaller modelling projects.

I gather clock makers use cutting broaches (rather than reamers) to fit these? A set of twelve Bergeon cutting broaches covering this size (and more) would cost about £30 – and an unbranded broach set about a third of that. So it seems to me that this is a much better option for me where small tapers are concerned – rather than buying small reamers (assuming I could get a metric tapered one this small) – or when I need to fit larger taper pin.

So, am I missing fundamental something here? I see the word "taper" and do tend to think "reamer" but I suspect a clock maker would instead think "broach".

Am I correct in this assumption or am I missing some basic difference between the two tools?

Regards,

IanT

With a small reamer, I would rather use a pin vise than a tap wrench. The hole size depends a lot on the size of the shaft if a gear is to be pinned to it. I have seen tapered drills, but not in sizes smaller than 1/8".

Edited By old mart on 28/11/2020 14:30:03