MadModder

Another TWIT moment of course - the bolt shank is 12mm - assuming that the 9.5 mm hole is approximately concentric (it isn't quite) then there will be (12-9.5) / 2 wall thickness left or 1.25 mm which will have very considerably weakened it but it's very  tough steel. I'll have a go with a punch and see if it'll shear off.Very well supported of course as it's snugly sitting in the female countersink.

(a 12 mm Cintride bit is north of 50 UK pounds)

It did occur to me that it possibly could be a left hand thread, but there is no valid reason why it should be as the tool disk is rotated in both directions by the servo with the logic working out which way is quicker from 'current tool' to 'desired tool'

I did however try left handed vigorously with the big ugga-dugga !

Well another try:

I've managed to drill a 6mm  hole 20 mm deep into the back of the hex driving recess using an HSS carbide drill. Went in remarkably easily. Next size up that I have in HSS Carbide is 8mm - total rejection, just polishing the edge of the hole. Tried another brand new HSS carbide in 8 mm with the same result.

I can only assume that the core of the screw has been left relatively soft with the rest at 12.9 hardness.

It seems that 12.9 steel needs to be brought up to 400 Deg C to soften and I'm getting no ware near that with my propane torch. I do have a Mapp gas cylinder but that only burn a few degrees hotter so probably not the solution.

I've a pair of big old Oxy-Acetylene cylinders out side in the safety cage but I dread to think what the state of their hoses is - not been used in a few years. The logistics of getting them near the bench will be challenging.

. . . more cogitation 

Still no joy. took it to just under 300 degrees C and held it there until my finger holding the torch trigger went numb!

Got the hex bit stuck in the hole, eventually freed clamping a Mole Wrench on it and using levers - this is getting silly. I dug out an extended length decent quality Allen Key and whacked it with a big hammer trying to shock it free whilst still pretty hot - no joy.

If I have too drill the head off the bolt it's not the end of the world as after all all I'm trying to do is see how this beast is held together before attacking the 'real' one, and don't intend to use this shaft, but a shame to ruin it.

CHATGPT tells me a counter sink headed bolt with a 25 mm diameter head and an 8 mm drive socket is probably an M12 thread so when it's all cooled down I'll see if it succumbs to drilling.

If it were me, I?d confirm the firing order?if they?re sequential then it?s a matter of lighting the leds to follow the sequence?using the triggering mechanism used for generating the spark for each?.

If this isn?t the case, then I?d need to know how the spark is triggered for each cylinder, using the trigger, this could be used to ?enable ? a transistor to drive? each led?

A bit more info please?.


Typing gremlins have crept in?