Author Topic: Impatient but RAF to the rescue  (Read 676 times)

Offline DaveS

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Impatient but RAF to the rescue
« on: February 21, 2017, 06:06:41 PM »
Partway through making a rear toolpost I had finished some of the milling and  next day decided to turn the holding down bolts 2 off 75 mm long 10mm dia. Before starting I thought better check I've got 10mm die, no, after searching through several drawers. Obvious choice is turning but with the abortion of the change gear set up banjo it can become a lengthy process. (I'm also in the middle of making revamped version)
As the thread type wasn't that important I'll go with 3/8 BSF. Check BSF tap draw, yes but only 3, check for 3/8 die, yes safe to go ahead. Bolts made and back to the mill to drill and tap the base. I hadn't really looked at the taps except to make sure they were the correct size. 2 nackered 1 st taps and a plug. First taper tap managed to put a chamfer at the top of drilled hole nothing more. Onto the next tap which did at least make a couple of turns, used the plug tap another 2 turns. Alternating between these two the holes were finally finished. How long did it take? I don't know my brain went numb.
Where do the RAF come in well hopefully the photo will show the tap clearly but was Air Ministry supplied in 1939.

Impatient   Dave

Offline DaveS

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Re: Impatient but RAF to the rescue
« Reply #1 on: February 21, 2017, 06:15:21 PM »
Before anyone asks if I brought it new, no I didn't have enough coupons

Offline John Stevenson

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Re: Impatient but RAF to the rescue
« Reply #2 on: February 21, 2017, 07:08:25 PM »
Amazing really because everyone build drill grinders, lathe tool grinders etc as they get blunt but they expect taps and dies to go on for ever.

Got these off me great granddad and he got them off George Stephenson.

End of the day they are a cutting tool and like ALL cutting tools they wear out.

CNC shop up the road from me a while ago had a big box, shoe box size of M6 spiral point taps on the side where all the rubbish goes. I asked what they were for and told they program then to cut so many holes and swap tools. When you look at them the tips were shiny. Told I could take a few if I wanted so wandered off with about 20 or so.

Got back, drilled a 5mm hole in a bit of steel and tried it out. very hard to turn for a M6 tap so yes they were blunt. Nothing to loose so tried a bit harder and snap, broken tap.
John Stevenson

Offline awemawson

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Re: Impatient but RAF to the rescue
« Reply #3 on: February 22, 2017, 02:41:14 AM »
I suppose if hand tapping in a home workshop using good quality hss taps they should last a lifetime. But if in a repair workshop where they perhaps are not used under ideal conditions, or in a production environment where usage is heavier then they must be considered expendable.

I think in other than a production environment the biggest killer of taps is the way that they are stored. I'm guilty of poor storage as although I have proper boxes with inserts for most ranges of taps and dies, I also have open boxes where they are just piled in rubbing together. Not good for sharp cutting edges.
Andrew Mawson
East Sussex

Online mattinker

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Re: Impatient but RAF to the rescue
« Reply #4 on: February 22, 2017, 06:24:31 AM »
At a pinch, you can sharpen taps, at a real pinch, I've done it with an angle grinder! It can get you out of trouble!!

Regards, Matthew.