Broken Taps

[tornitore45]

Just an idea. Since is a through hole, I would cut indentation on the tip of a dowel. As many indentations as the No of flutes and try to drive the tap out from the back. Less risk to bugger the hole.

[Bill Shields]

Excellent advice if you want to burn it out.

Any place that has a WEDM machine will most likely have an EDM drill if you want to go that way.

[tetramachine]

Second the ball end mill. If the tap protrudes at all above the surface, here's the way I have done a few times, 100% success.
Take a piece of steel scrap, drill a hole thru the size of the tap, then drill a hole say 1/4 but not thru, leaving a shoulder at the bottom. Now mig weld the hole full. If all went right, you just unscrew the scrap and out comes the tap. And the AL should be unharmed.

[gwrdriver]

Take a couple of days off (from your current project), build yourself a simple tapping stand, and eliminate 99% of broken taps. I did and it reduced my small tap (#0 to 1/4") hand-tapping breakage to Zero. (I also always use a good tapping fluid.)

[Steamer Al]

I use one of these, and have never broken a tap with it. I use it in the lathe as well for tapping small holes

Im not affiliated with KBC tools, other than having spent a few paycheques there over the years...

https://www.kbctools.ca/itemdetail/1-397-513

Alex

[Wolfgang]

Years back when I had no kids and a lot more free time I thought a flat rate tap removal business would be a cool model. Idea being that the customer ships you part and a return label you burn it out with an EDM tap burner and ship back for a fee. It seemed like quite the little niche side gig. Is there anyone doing this. There's a lot off parts I would happily pay $50 for a tap to be removed over the years.

I offered such a service perhaps 25 years ago by sending a FAX to every business I thought could use my services. Got no takers.

Over the years I have done jobs for friends who broke taps in British model engine castings, or forgot lubrication holes in heat treated 17-4 PH shafts.

Where are you located? I live 1 hour's drive south west of Toronto.

[ToddMiller]

I second the alum method Ironflyer mentions. I used it recently in the same situation, a broken coated tap in a bronze part. I put the alum solution in a double boiler to keep it warm without drying out. I bought my alum from a farm store that sold pickling supplies, it was $9.00 a pound. The spice aisle was $5.00 for a couple tablespoons. I am set for life.

[RET]

Hi,

A long time ago I asked my dentist if I could get a couple of his used diamond burrs. He gave me a few and I've used the cylindrical ones with a Dremel to remove a couple of taps without damaging the hole. They work very well, but its a slow process.

What works even better is to not break the tap in the first place!

For instance, if you want to tap #5-40, then use #4-40 as a pilot tap to remove some of the material first, before going through with the #5-40 tap. Also, since I have taper, plug and bottoming taps for all the common sizes I use including #0-80 (all stored in a hardwood block for easy access), I work back and forth with each one to remove material in stages. Don't forget to use a good tapping compound, it makes a great difference. Varsol works perfectly for aluminum.

For the larger sizes, there is #6-32, #8-32 and #10-32 so you can use the same technique there. I don't use # 6-32 because that size tap is the easiest to break and #5-40 is 1/8" dia. anyway.

I have always used the above techniques, so I don't break very many taps.

Richard Trounce.

[Greg_Lewis]

And buy quality ones and don't hesitate to toss one in the bin if it seems the slightest bit dull.

[Bill Shields]

And buy quality ones and don't hesitate to toss one in the bin if it seems the slightest bit dull.

the trick to not breaking taps is to throw a lot away

have a good friend (now deceased) who had 48 holes to tap 2-56 in his cast iron cylinder castings (this in 1950)

he purchased 48 taps (all carbon steel)

built a guide to be sure they got started

one hole -> one tap -> he got through it driving them with a pin wrench with a rubber band wrapped around the outside for grip

i have a box full of 'slightly used' 2-56 taps that are older than i am....and a very nice looking semi-finished loco