Taper reaming

[Bernard LaycockParticipant @bernardlaycock66604]

Could anyone please help me by describing the process of making and using taper reamers?

[Bernard LaycockParticipant @bernardlaycock66604]

[Ian ParkinParticipant @ianparkin39383]

Not sure about the process of making one but to use ….you use one by hand turning clockwise with a tap wrench untill your taper pin fits the hole smoothly after drilling a hole to the smaller diameter of your preffered pin

[Speedy Builder5Participant @speedybuilder5]

[Speedy Builder5Participant @speedybuilder5]

LBSC describes making taper reamers for injectors similar to a ‘D’ bit. Ie:- turn piece of silver steel to the taper required, then file away half the diameter (along the length of the taper) then harden and temper it. Stone the cutting edge such that it is ‘sharp’.

 

Usualy these are short and used on bronze material.

[KWILParticipant @kwil]

If you are seriously interested in making these reamers, which must be at a very accurate angle, then I suggest you buy D A G Brown’s recent book Miniature Injectors inside and out (TEE Publishing) an excellent and complete approach to all of this, including the reamers. Usual disclaimer

[“Bill Hancox”Participant @billhancox]

Hello all. The method I use is to drill the pilot hole using a slightly under size step drill that best matches the size of the taper reamer that you wish to use. I buy my step drills and my reamers from a New York firm.

Cheers

[Sam StonesParticipant @samstones42903]

 

To add to Ian’s comment about turning the reamer in a clock-wise direction. As with any (fluted) reamer, never reverse the direction of rotation of a reamer as you do when tapping a hole.

 

Also, having turned several sprue bushes for plastics injection moulds, keeping the reamer in line via the tailstock was automatic. However, if you are hand reaming, you may need some form of steady or pilot to ensure proper reamer alignment.

 

Back in the 50’s, we made our own HSS taper reamers. The taper was often an odd angle, as a result of the non-standard mould geometry. On one particular occasion, it was my job to make the initial turned blank. This was then fluted by one of the milling machine operators before it was hardened and finally ground to size.

 

The trouble emerged when it was discovered that the milling machine operator had cut the flutes in reverse. There wasn’t enough time to make a new blank, and eventually, I had the job of reaming the (one-off) sprue bush with the lathe running backwards.

 

You may think that it would have been an easy task, except for the fact that I was still an apprentice working on a much neglected lathe, and, the lathe was driven from an overhead counter-shaft, via flat pulleys, ie. NO REVERSE.

 

The solution was that we crossed the secondary belt, while keeping a very close eye on the possibility that the lathe chuck could unscrew at any moment.

 

Fun days!!!

 

Sam

Edited By Sam Stones on 02/03/2011 06:10:56

Edited By Sam Stones on 02/03/2011 06:13:42

[Gordon WParticipant @gordonw]

I’ve only ever made one taper reamer ,for a one off job.Easy way to get the taper accurate is to make the reamer, and the bit that fits the hole, at the same top-slide setting. Then carry on as above.

[Bernard LaycockParticipant @bernardlaycock66604]

Thanks for you comments, guys.

Sam, I never realised taper reaming could be so exciting!

KWIL, I followed up your recommendation with TEE publishing, but could not find any reference to it in their list – can you help with a location?

Regards

Bernard

[KWILParticipant @kwil]

Bernard, go to Tee Publishing website and under “operation, valve gear and injectors” you will find the said book, I have a copy and it is very good.

 

K

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