Useful tools and techniques

[ekd]

The fingers wedge at the bottom, trapping the tap at both ends.

They are called Walton Tap Extractors. My set of 16 goes from 25mm to 3mm (and fractions between), and they hurt like H when you pay for them. But, not as much as not having them, when you break off a blind hole tap (as always, recessed and presenting a 45deg face) in a blind hole in a part you have 2 days w/OT into...

Happy to help, guys. I've been dead weight to date (but I'm working on that!).

E

[ekd]

A couple more things...

A drill press makes a great tap starter if you:

Unplug it.

Find the largest dia rod (I like drill blanks) that will go all the way into the chuck key holes, and put a small radius on the ends (for quick, repeated insertion). A drill bit, with the shank inserted, works well for this, but you must wear heavy gloves at least until you get a feel for the particular task. Breaking a drill bit while your hand is around it will quickly produce predictable (and quite possibly, crippling) results.

Good blind holes can, and should, be made in two steps. The shape of the first few threads is critical. Always start the process with a regular (tapered) tap, and gently run it to the bottom before switching to the BH tap. The BH is meant only to cut the last few threads.

Finish all tapping by hand, switch over as soon as you have a solid, straight start... Unless you have extractors.

It also helps to simply buy quality cutting lubes designed for the metal involved (I use Tapmatic). The most cost effective machine shops (on this planet) buy the stuff, at real cost to themselves, by the gallon. The reasons will be crystal clear to you upon setting the first screw.

Have fun, take your time, and the results will speak for themselves.

E

[ekd]

Build one of these. I'll be happy to show you how (w/o a machine shop) if desired.

This is a spindle wrench for a mill I'm (still) building, and it makes for quick and effective use of any press (w/a free quill) for any manual operation. Use a rod for the first couple of threads.. Then Rock and Roll!

The tool should be no longer than necessary to apply proper torque to the biggest tap you will be using, for better "feel" and more speed.

A nice setting rod can be made by taking an old drill bit, and making a sleeve handle that exposes only enough of the bit shank to fill the chuck's keyhole. Attach with epoxy, as brazing will apply enough heat to lose the temper.

Hoping this is helping...

E

[rif]

I live in a small NYC apt and don't have room for a drill press. Where can I but one of those drill guides that was shown many posts back?

Or would anyone build one for me? (I would fork over a few $$ of course!)

[Peter Daniel]

You can get them from here: http://www.yardstore.com/tools/drilling.htm

Check item # PN:13070 Plastic Drill Cup Only
Additional bushing required.

BTW, this is a very good ( and pretty cheap) supplier of aircraft tools. I spent $200 there, once

[dice45]

Originally posted by neutron7
I have a small hint for anyone who is cutting or drilling plexiglass or other hard plastic materials.

Dish washing liquid makes excellent cutting oil
I used it to cut a 4" diameter hole in a peice of 1/4 inch plexi with a fly-cutter in my drill press and it worked great!

I picked it up from the Taig minilathe mailing list.

Originally posted by Magura
Plain water does the trick as well....and is a little less messy.

Agreed.
Point is: cool the plexiglas chips enough so they cannot melt and spoil the freshly cut surfaces. I observed our lab mechanic milling plexiglas and perspex parts completely under water (he improvised a water trough on the mill's machine table). Result: the freshly milled surfaces were as smooth and clear as if they had been polished.

[Peter Daniel]

That's an interesting technique. Nice to see you back, Dice.

[Magura]

Since I usually CNC everything, I just use the regular coolant as used for metal. It contains 7% oil. Most CNC mills have huge coolant pumping capability, so you can easily keep it from melting the material. With such i have experienced the same as Dice45 mentioned.

Magura

[fcel]

Dice45,
15 months is a long time to be away. Any interesting stories to tell? If yes, please start a new thread.

[planet10]

Bernhard,

Good to see you back

dave