Thread: Taps & Dies

Originally Posted by Woodlee

Don't know about chucking them out when the cutting edges get dull ,they are easily sharpened .I have sharpened taps and dies with a die grinderand a small cylindrical stone or mounted point quite sucessfully.You could use a dremel even..

Dremel with Diamond impregnated cylinder bit works great!

Broken taps and milling cutter make good cutting tips don't thy expressly for boring bars

I've even used a broken 1/4" drill sharpened like an end mill to mill a slot in aluminium.
Just ground on the bench grinder by hand .
The top drawer in my machinists tool box has a collection of broken taps and drills amoung a whole lot of other bits and pieces.The drawer is only an 1" deep but it holds a wonderful collection of stuff collected over many years.
Never know when you'll need a small piece of tool steel.


Kev.

If a tap is simply blunt on the cutting edges it can be restored by grinding in the flute. This may or may not be completely successful as the flutes have a specific rake angle and the rake angle must also be restored. If the tap is rusty on the threads it is a chucker in my shop. Rusty threads will bind, especially in tough steels and aluminium. A tap that binds is far more likely to break especially if tapping brass.

Using broken taps reshaped for use in a boring bar is a great idea. Unfortunately, this only works if the tap is made from High Speed Steel. The "normal" high carbon tap is only good for a few minutes, even less time than it took to make it. A broken drill, hand ground for an endmill replacement, also works but its only a tool to get you out of trouble when really stuck, been there, done that and its hardly worth it.

The very best taps are made from HSS and are Tin coated. These are what I used exclusively when I ran my gunsmithing business. For tapping aluminium, a Tin coated tap that swaged the thread was far superior to anything else. For tapping steel and other similar metals, a "gun" tap is wonderful to use. A gun tap pushes the swarf (chips) ahead of itself and the flutes stay clear of chips. If you have never used one of these, get one and try it out.

Searching for tapping tables can often be a pain in the neck if you dont have the tables book in your pocket. I can determine the drill size for UNC and UNF threads before you can find the book or walk to the chart on the wall. I have a program in my programable calculator to determine all UNC and UNF tapping sizes. The calculator makes it very easy and quick but only if it can be programed to suit. More on this later.
Kody

Personally ,I can't see the benefit of a calculator to work some thing out that's already been done ,why re-invent the wheel ?

I've had my Sutton booklet since I started my apprenticeship ( got it free from Sutton rep ),it has never let me down ,doesn't need batteries or isn't solar powered,won't fly to pieces if it gets dropped and is close at hand in a drawer in my machinists' tool box, right next to my lathe.
It not only has tapping charts ,but drill size equivalents , speeds and feeds for drilling different materials and sharpening angles for same .Hints on tapping different materials and what lubricants to use.Then as you move through the pages ,there is information on milling cutters and speeds and feeds for them.
That's just the Sutton Cutting Tools booklet ,,, then I have the Engineers' Black Book , the Moore and Wright booklet and the Zeus publication , these all compliment the Machinerys' Handbook which I won as a prize for my efforts during my apprenticeship.

Rust can be removed from tools using cleaning vinegar ,citric acid or electrolysis ,with out damage to the tool , clean up with hot soapy water and a soft brass brush then spray with CRC or equivalent .
I even sharpen my files with cleaning vinegar .

I have a ton of end mills and slot drills ,some high speed steel and some solid carbide ,but that day I didnt have a 1/4" endmill so improvisation was the game.
Sharpening broken a drill to use as a milling cutter,,,, well ,it was worth it to me ,took only a few minutes and it got the job done .
On occasion , when in need ,I have made a tap or two , to restore wierd threads I have come across during the restoration of old tools and machines.

I don't have the luxury of running down the street to buy a new cutter , the closest engineering supply is 320klms away.
Some times we just have to make do with what we have.

I don't work in my trade any more , and the metal working is just a hobby for me . Soon I will have a bigger lathe and also a large milling machine ,just to make it more pleasurable.
You wont find a calculator in my workshop , I use my soggy brain for any stuff that I need to calculate , keeps the grey matter in tune.
E=MC/sq

Kev.

What a wealth of information

Broken taps I've had a few top brands to they are often harder to remove where chink ones crumble at the sign of removal tools.

I have taps left over from my apprenticeship days still cut fine for my needs at this stage, not long ago I bought a cheap cheap set of Metric & UNF for some simple jobs real light work they are ok.


What gets my goat is the devices for holding such as taps and die's for hand held use crap the lot of them T handles that bend, snap the eye's they go through break, jaws/collets that are rounded before use and wont tighten onto anything


I have scored some 2nd hand stuff over the years and have found that most are great and have been cared for by the previous user.

Lots of good stuff here - just getting into taps and dies - thanks fellas !