My Morse taper gave out when drilling  brass  on my CC lathe. The
drill digs into the brass and then the taper slips. It took me hours
to drill a 2 inch hole in the 3/4 thick aluminum bar shown keeping
the taper chuck from rotating. It holds when drilling  aluminum or
steel.

The reason for the brass interior part was because aluminum would
generate yellow snot when flowing methanol.

These injector holders are high precision. The adjustable 3 jaw chuck
on my CC lathe was under a 1/2 thou run out. This design would not be
possible with out that.

Basically it is built around 37 degree flare fitting AN-6  to 1/4
inch pipe steel adapter from McMaster Carr. Under $3 each. And 5/8
diameter brass rod insert. That had to be machined down as the
diameter tolerance was all over the lot.

In terms of hours of engineering, design and machining at $50 an
hour they are worth well over $500 each :-)

The tiny drilled head SS 6-32 screws are also from MacMaster. This
was a precision operation as well as the hole depth for the screws
was limited to exactly .2 inches or one would have a 150 psi leak.
There are only about 6 threads in the hole. Once they are safety
wired they just act as retaining pins. The mechanic better go easy
with the screw driver :-)

The .040 aluminum straps holding the whole works together are not
shown. They will be tig welded to the large intake tubes.

This 200 pound 2 rotor engine is generating  650 HP with only four
injectors. PAC in Oz used eight for some strange reason. Maybe they
have not heard about the Bosch 2000 injectors :-) Maybe that was for
a 4 rotor.

Paul Lamar

It's probably not the Morse taper that was the problem - More likely
you were using a drill ground for steel - For brass you need slightly
different angles on the drill point and that problem goes away

Roland  Friestad

I did not know that Roland, Thanks for the tip.
I at first thought it was the 13 mm drill bit I paid $40 for.
Then I bought a 39/64th for $40 and that was only a bit better.
I never saw a brass drill for sale.

Is there any way to fix the male taper on my taper chuck? It is scared
up pretty bad. Must I buy a new one. Hopefully the taper will be harder.

Paul Lamar


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