Urgent Q: Tap & Die set?

[shedracer]

I`ve bought a tap and die set, as I need to tap a piece of aluminium ASAP. Question is the set has 2 sets of each size, ie: M4 tap, one is M4x 0.75 and the other is M4x 0.7, whats the difference and what size drill would I need to use?

Waiting with anticipation.

 

[Wizard]

In aluminium, 3.2mm hole should do unless you've got a very good/accurate/straight pillar drill. Turn the tap a wee bit and take it well out, back in another half turn and back out and so on. Use plenty of oil to flush away the swarf and lubricate the tap (assuming you don't have proper machining fluid/water based lubricant).

The 0.7/0.75 difference is the thread pitch (distance between the peaks of the thread). Run the screw alongside the tap and see if the threads match if the kit didn't come with a pitch gauge (looks like feeler gauges but has one serated edge on each leaf)

HTH

 

[ianboydsnr]

If what i can remember, the .75 is the thread pitch, so for the .75, you would need a 3.25 drill, not sure about your different pitch as all i have is M4x .70, this uses a 3.3mm drill

 

[Tarka]

Don`t forget that when tapping aluminium,the correct lube is paraffin...


The tapping drill size is the same regardless of the pitch.....I`m just not sure 'off the cuff' what the correct M4 tapping drill is.....and I`m not at home to check it.


I fink it`s 3.2mm.

 

[ELIMINATOR]

tarka, consider yerself slapped

On metric threads, the correct tapping drill size is the tap size minus the pitch. 4 x 0,7 is 3,3


4 x ,75 is 3,25

Admitedly not as relevant on this size thread, but let's get the facts right.

Wizard, unfortunately you've chosen the same name as a crap brand of taps we once used.

 

[Tarka]

tarka, consider yerself slapped

Okay...okay...that`s me slapped



Mind you....it`ll all be irrelevent when the drill`s gone off centre due to the wonky chuck in the knackered battery drill that`s being used

 

[ELIMINATOR]

Not to mention being tapped on the piss by an amateur

 

[Wizard]

There ya go shedracer, that's how NOT to do it. So don't forget to post pics now that we've intimidated the crap out of you the first time you try a fairly tricky piece of fabrication work

 

[(RIP) Kaister]

if you're really good - you'll drill the hole, quickchange to the tap, tap and reverse in one go

all with a rechargeable drill




......and its a blind hole

15 sec tops

 

[shedracer]

Cheers guys, very helpful indeed. Now you might wonder what I was up to, so here's what it was. My gps mount for the 276c on my gsa12.

All sorted now and I tried it out tonight, its just what I wanted. My good friend Trevor Miles, knocked the ally mount up for me yesterday, all I had to do was make a small mod and it was sorted.

I`m really pleased with it, Trev your second to none mate.

 

[Wizard]

My gps mount for the 276c on my gsa12.

Now that's a nice bit of fabrication

 

[(RIP) Kaister]

machining - not fabrication

 

[Tarka]

Looks good

 

[Wizard]

machining - not fabrication

The other guy machined it, he assembled it on the bike. Fabrication
















Yes, I know. Assembly. Pedant.

 

[thornley]

Nought wrong with pedants. Its machined and assembled in situ. Not fabricated

 

[(RIP) Kaister]

The BMW GS1200 is the perfect round the world bike - now THAT'S fabrication.

 

[thornley]

I have 5 kids all 5lb 6oz at birth. thats precision grinding