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Injector Manufacture

Small taper reamers?

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David Haynes27/10/2012 08:39:23
168 forum posts
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I must first say that I am not currently making this and I know many will say to go and just go and buy one! In LBSCs account of the Mona injector, for the divided combing cone, he talks about using a 7/32" dia brass rod, drilling it with a No. 72 drill and then opening it out with a 3/4 in tapered reamer. My query is, firstly 3/4in is too large for a No72 (0.026"  hole and I don't see any small reamers advertised anywhere.

I would be grateful for your thoughts.



Edited By David Haynes on 27/10/2012 08:50:44

Edited By David Haynes on 27/10/2012 08:51:19

Edited By David Haynes on 27/10/2012 08:51:41

JasonB27/10/2012 08:53:08
22751 forum posts
2653 photos
1 articles

Does he mean a taper of 3/4" per foot?


Stub Mandrel27/10/2012 18:45:02
4315 forum posts
291 photos
1 articles

I've seen an article somewhere with injector reamers ground as profiles in bits of hacksaw blade. Feasible as they only have to cut brass/gunmetal.


Oops that's "profiles" not "proles" - I don't want to be mistaken for the Chief Whip!

Edited By Stub Mandrel on 27/10/2012 18:46:04

AndyP27/10/2012 21:08:00
189 forum posts
30 photos

In Shop, Shed and Road Curly gives instructions for making the taper reamers for injectors from 5/32 silver steel and refers to one as a 3/4" which is made by setting the topslide over about 6degrees to cut a taper 3/4" long on that diameter stock. Another one is 1 1/8" of taper by setting over 4 degrees. He later refers to the first one as a 3/4" reamer when making the combining cone.

Makes it sound so easy doesn't he ?


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