Ultra-Small Boring Head

[Bill Gruby]

I was close, rough count is 405 parts.

"Billy G"

[stevec]

Wow!

[claudef]

Nice work Bill.. I love these small projects.
Building 18 cyl. Radial however is a real challenge, both in skills and time.
I’ve been following your build and studying the design, your gib Det.3 is held in place with 2, 4-40 SHCS, then you have a 6-32 Set screw that will lock the boring head after adjustment. Is this set screw supposed to bow the gib in the middle and clamp the moving part of the head. I realize that this is a light duty head but there are better ways. Your pictures are great keep them coming.
Am I missing something here. Claude

[Bill Gruby]

Claude;

The two outside cap screws are never overtightened. They keep just enough pressure on the gib to make a lite friction movement. The center set screw will bind without over pressure to bow the gib because of the lite screw pressure. The center set screw is what actually keeps the gib tight.

"Billy G"

[Highpower]

(01-25-2013, 08:34 AM)claudef Wrote: ....Is this set screw supposed to bow the gib in the middle and clamp the moving part of the head. I realize that this is a light duty head but there are better ways.

I thought that was pretty much the standard way of doing it?
My Criterion head even has wax plugs over the outer screws to keep you from fiddling with them, and the center screw is marked "LOCK".

2 inch boring heads:

[Bill Gruby]

Yes Highpower, most all heads are this way. You don't think about it till you build one then it seems strange. Actually all the outside screws do is hold the gib from falling out. They are only threaded into the gib. They pass freely thru the body.

"Billy G"

[Bill Gruby]

FAITH --- The ability to go forward with no guarantees.

Almost there. I will finish up the slide except for the Dovetail this afternoon. Then all that is left is the Dial (5) and keeper (7) . They should be done today also. UPS say Dovetail Cutter will be here tomorrow.

"Billy G"

[claudef]

Agreed that most boring heads have these screws but the gib is normally part of the head and is rigid, in this case the gib is loose and held in place by the threads of the SHCS and the pressure of the set screw. I would think that under pressure this gib would have tendency to lift and cause chatter.
Now if you had two other screws holding the gib down to the head after adjustment that would surely help. I presume you will have the boring tool pointed towards the adjustment dial, that way the cutting pressure will be against the solid dovetail side.
Anxious to the next steps, specially when mounted to work on the radial.

[Bill Gruby]

It wont be a problem when it is finished. OK -- The boring tool holes were bores with a .370 Carbide Endmill and reamed to .375. It's ready for the set screws and will be done at that point waiting on UPS tomorrow.
Think I'call it a day after drilling and tapping these three holes. The flu is still hanging on and I'm tired.

"Billy G"

[Bill Gruby]

Days end for me. The three tool holder setscrews are done.

"Billy G"