[Mitsui Seiki]

Was the bushing used with the spade drill or the boring tool?

[AMCjeepCJ]

Was the bushing used with the spade drill or the boring tool?

The boring tool!! Just look at the pics... He's being ridiculous...

[Mitsui Seiki]

The boring tool!! Just look at the pics... He's being ridiculous...

I know it's for the boring tool.

[AMCjeepCJ]

I know it's for the boring tool.

lol, sorry, I knew you knew, I was still wound up when I wrote it... I kind of wonder why I even care but it bugs me he keeps insinuating everyone is a liar because he can't do what we can... lol and we can do it on crappy ass equipment if need be~

[dapoling]

lol, sorry, I knew you knew, I was still wound up when I wrote it... I kind of wonder why I even care but it bugs me he keeps insinuating everyone is a liar because he can't do what we can... lol and we can do it on crappy ass equipment if need be~

A typical statement by those uninformed, I bet you can drill a hole smaller then the drill size being used.

[AMCjeepCJ]

I quit, you win......but just so you know, it is possible for a common twist drill to drill an undersized hole in metal... I'm looking for the technical write up on it but until I find it, let's just chalk it up to fantasy...


Until then, I just wrote a poem for you...using your zone name:


Damn..........I'm super-duper smart,
And Geof, you didn't build those parts!
Please tell me I'm the best,
Only ignore that I'm a pest...
Lies are what I find
In the posts you leave behind
Now bow before my throne,
God...........why am I alone??

L8R T8R

[Geof]

I quit, you win......but just so you know, it is possible for a common twist drill to drill an undersized hole in metal... I'm looking for the technical write up on it but until I find it, let's just chalk it up to fantasy...


Until then, I just wrote a poem for you...using your zone name:


Damn..........I'm super-duper smart,
And Geof, you didn't build those parts!
Please tell me I'm the best,
Only ignore that I'm a pest...
Lies are what I find
In the posts you leave behind
Now bow before my throne,
God...........why am I alone??

L8R T8R

Very good!!!!!!!!!!

Although nit-picky me is going to pick you up on something. Your drill doing an hole under the drill size: Is it a round hole or is it what I have seen called a constant diameter hole? I have seen these, I have done these: They are kinda multi-lobed holes and one cutting edge of the drill kinda goes out into a lobe so the opposite cutting edge is cutting below the drills nominal diameter; the drill sort of wobbles its way down the hole. But because the drill has a helix the lobes are not parallel withn the axis of the hole they follow the helix. The net result is that, provided you are not dealing with a big drill, the wobbles are very small and not really noticeable among the rought surface normally left by a drill so the drill appears to have drilled an undersize hole.

And how come I claim to have seen and done this? I made a fixture once that was intended to clamp some 5/16 material in a hole about 1-1/2" long. The two halves were faced nicely and tightly bolted together and the hole dilled carefully down the joint line; first using a 17/64" pilot hole. The 5/16" hole came out 'undersize' and when the two parts where separated it was possible to see the helical pattern on the walls of the hole.

So I figured it was because I had the joint line causing some deflection, and made both halves too thick, drilled the holes under the same conditions but this time in solid metal and then faced off the excess to expose half a hole in each side.....virtually identical!!!

But the fixture worked.

I'am not retired, yet; what's my excuse for spending time here? It is fun even if some people are irritating beyond comprehension, and anyway most times my machine(s) is (are) doing something. That is the TL2 and SuperMiniMill I have in a workshop behind my house for developing prototypes and building tooling. I work here for peace and quiet and because the production machines are pretty well tied up all the time.

[Mitsui Seiki]

A typical statement by those uninformed, I bet you can drill a hole smaller then the drill size being used.

I shouldn't be saying this but ,yes. A hole drilled with 7mm drill measured 6.983.In Stellite.Engine mounts for Airbus.Actually several holes.

[Geof]

I shouldn't be saying this but ,yes. A hole drilled with 7mm drill measured 6.983.In Stellite.Engine mounts for Airbus.Actually several holes.

Stellite? Kinda like a hard bronze? Or should I not be saying this.

Actually a very hard bronze to be picky I think. Do they actually make the entire engine mount in Stellite?