Carbide Scraper-Deburr Tool

These are directions for how to build a simple Carbide Deburring Knife...
 I did this build at The TechShop in San Jose California...
http://techshop.ws/
 Gabriel Aceves

Step 1 Materials...

Ok we are going to need, 6inch length of 1/4 alluminum rod,
 1/8 inch carbide shank ( I used a
 broken .125 endmill), .120 inch drill, .124 inch reamer,
Grinder capable of grinding carbide

Comments

[ironsmiter]

Since you have the vice already... use it to PRESS in the press fit carbide piece.

provided it can open up far enough


Or, even better, since you used the lathe...
put the carbide in the drill chuck of the tail stock, the handle in the headstock chuck. and use the tailstock advance wheel to press the piece in.

One advantage is, you don't actually need to remove the handle after it's drilling operation. Once drilling is done, you can either ream in place, or, if your drill happens to be sharpened a little off, it probably drilled a bit over sized.
As long as you are close to .0005 under sized, you should be able to make the press fit without trouble.
Even if you end up drilling .001 or .002 under size, there is a trick that doesn't require a reamer.
Heat the snot out of the aluminum handle with a propane torch. You can actually do this right in the 3-jaw chuck. If you're careful, and don't have oil all over the work/chuck/lathe.
The expansion from the heat will open that hole right up a couple ten thousandths. As long as you're quick with removing the heat, and pressing the carbide. I suggest a second set of hands, and a "Three. Two. One. GO!"

For the math fanatics... Aluminum is right near 13 microinch/(in*degreeF).
That makes close to .0005 extra clearance with a "safe" 350F temperature change. You could push as high as 1000F(1.5 thou expansion). but that'd be getting pretty near melting temperature.You'd be just as likely to before your handle, as get a good press fit.

And here come the shocker of all that mumbo jumbo.

Given how soft aluminum is, and a good rigid lathe like you have(no desktop models for THIS job)... you should be able to do the press without even reaming.
I've done .125 steel dowels into .120 holes quite a few times in brass, aluminum, and even silver. A good straight lineup, and a chamfered edge on the piece being pressed in is essential. Other than that, it's just a little muscle. And best to press it all the way in one turn of the wheel.

Sure, .005 is a LOT tighter than .0005, but you're not going to be taking this apart anytime soon, right? :-)

[ironsmiter]

oops. forgot to say how I did it...

Drill press, and a clamped vise.
Once the hole is drilled and cleaned, I put a TINY chamfer(.005? just "a kiss") on it using a center-drill.
then switch the drill out for the thing to be pressed.
Crank down on the handle, and press fit in no-time flat.

[Bongmaster]

neat :)

tho its 'until' not intell ;)