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7 mm grub screws
Posted: Wed Sep 20, 2006 3:11 am
by KingDom
I have removed the aluminium plugs from my 2.0 litre crankshaft and put a tap through to make a 7mm thread. (I broke 3 taps doing this process!).
I now require 7 mm grub screws.
Does anyone know where I can get these? Preferably in Australia.
I could use bolts sawed off after tightend in position but prefer socket headed grub screws for ease of removal.
Thanks,
Dom
Posted: Wed Sep 20, 2006 8:06 am
by Mats
M7 grub screws? And I thought it was difficult enough to find regular M7 screws...
Posted: Wed Sep 20, 2006 8:28 am
by sh0rtlife
try a local bolt shop..and id be suprised if they couldnt order it for you
Posted: Wed Sep 20, 2006 10:16 am
by Barry
I had a terrible time finding M7 grubbs....
Took a masonary drill bit,ground the tungsten tip to 6.8mm wide,drilled the crank and then tapped it m8...
V6`s I fit m14 pipe plugs...
Posted: Wed Sep 20, 2006 4:57 pm
by x-rad
I got 8mm plugs, seeled them, and peened them in with a hardened chisel.
Posted: Wed Sep 20, 2006 11:25 pm
by Mats
One thing I don't get in this crank business...
Why is it so fricken hard to drill the holes? The depth of the hardened bit should not be very large?
Posted: Fri Sep 22, 2006 6:07 am
by TS_turbo
those cranks are forged hardened steel..very dificult to dril or tap
.. i broke 3 taps and 2 dril bits in single nord crank
second dril bit broke deep.. then i sealed oil holes of 2nd main jouurnal and driled direct oil way trought main oil galery to 2 and 4 main bearings
7mm grub screw
Posted: Fri Sep 22, 2006 4:36 pm
by KingDom
looks like I will be inserting 7 mm bolts tightend into position then saw off flush to the crank web.
TS_TURBO is it necessary to plug the main crank journals of 2 & 4 after drilling in the block for additional oil supply to the bearings 2 & 4
Posted: Sun Sep 24, 2006 7:00 am
by TS_turbo
no its no need, i just blocked oil feed to 2 and 4 main bearing when i broke drill bits inside
Posted: Sun Sep 24, 2006 8:25 am
by Barry
If you guys use a masonary drill bit with the tungsten tip,it will drill the nitrided crank like mild steel.Slowish speed and gentle pressure.
Like a hot knife through butter..
I dont know why you guys battle with this.
Posted: Sun Sep 24, 2006 10:54 am
by MR2 Zig
As Barry said, or, you can go to the local industrial supply house and get an appropriatly sized carbide bit. Also, don't drill your holes using the regular drill chart that uses 75% thread engagement, use a drill size that has 60% engagement and you'll not be breaking your taps.
As your steel gets harder/tougher you will need to slow your drill speed (rpm). Alignment is critical as the carbide bits, while very hard, are brittle and won't take a side load.
HTH,
Scott