We start to wind up field work for the year, make a start on fixing the poly tunnel door, and on Wednesday, for my sins, I help to fit a new vinyl roof to an aircraft hangar! Nobody died so that was a good outcome! The 2cv tractor is rescued from the healing weeds, and soon its back to the nice warm workshop! video goes live at 4-00pm BST.
I got one of these recently. Wifi camera that fits into @5mm holes, with built-in led light, works with your phone and only a tenner or so. I'm not stupid enough to use it for its alleged purpose but it's ideal for examining deep, narrow bores like yours.
The bolts arrived at last: First task reduce t he last few threads as suggested by Mike, but how to hold them. Normally I'd take a suitable nut and saw cut to make it into a split collet - but no 7/16 UNF nuts. Ah but I do have a 7/16 UNF Die - naughty but it'll work:
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Now we need 'pushers' as the hole is deeper than the bolt thread:
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So screw them in and see if they work - answer YES!! though I have to make progressively longer pushers.
We have lift off:
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That's enough excitement for one day - I have to go to Heathfield and buy some sheep wormer !
« Last post by smiffy on November 06, 2026, 06:01:05 AM »
Before using the bolts it might pay to reduce the last couple of threads to the root diameter in case when tightening the bolts the last threads are damaged and expand into the taped hole making them difficult to remove. I speak with experience of this happening . Mike
« Last post by awemawson on November 06, 2026, 05:52:40 AM »
Still waiting for some 12.9 grade bolts to use as potential extractors, but in the mean time I've tapped those two 9.9 mm holes out to 7/16 20 TPI. 15 threads so 3/4" deep should give enough thread engagement I hope.
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There seems to be a distinct ridge in the hole about 25 mm down as though the front disk in the centre of the tool disk is a separate part - perfectly possible that the bolts trap it against a flange I suppose. Can't get a decent picture down the tapped hole but it's more visible removing one of the holding bolts.
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If the bolts arrive tomorrow all should be revealed
« Last post by awemawson on November 04, 2026, 09:12:51 AM »
Curiously the larger of those holes in the rows of three is precisely 9.9 mm and shows no sign of ever having been threaded. It does as far as I can tell go all the way through to the flange - this is assuming that there is a slight locating recess in the back of the tool disk, which the drawing does seem to confirm.
So what thread has a tapping size of 9.9 mm ? Chat GPT tells me 7/16 UNF 20 tpi so if this is true I shall tap those holes and see what happens ! Obviously can't tap right to the bottom UNLESS i CAN PRODUCE A 7/16TH UNF tap with a 90 degree end which should be possible if I have enough standard taps to sacrifice one.