Comet timing chest

[greg brillus]

Good advice from vince998, only other thing i would check is the original hole that you had trouble with.....sounds as though it may have picked up on the way in and broached the hole, possibly the spindle was a bit crooked as it went in....not too sure on that one without seeing it, but at any rate i would carefully clean up the hole which is a tough ask as a fixed 3/8 reamer will open the hole too large...others on the forum may have an idea or two but maybe use a long 1/4 bolt with the head cut off and cut a slot down one end, then fead a piece of emery tape into the slot with the tape wrapped around the bolt a couple of times and spin it in a hand drill. You can then a little at a time ease away the high spots down the hole, try keeping the tape from removing alloy at the mouth of the hole to prevent it bell mouthing too much......good luck....Greg.

 

[vince998]

Or buy a dremel!!
I have pictures of the cases wanging around the room held onto the drill with a slotted headless bolt and emery cloth!!
I made up a set of scrapers from some needle files for jobs like this. Takes a bit of time and patience, but you can see what your´re doing, and only remove what you want to.

Good advice from vince998, only other thing i would check is the original hole that you had trouble with.....sounds as though it may have picked up on the way in and broached the hole, possibly the spindle was a bit crooked as it went in....not too sure on that one without seeing it, but at any rate i would carefully clean up the hole which is a tough ask as a fixed 3/8 reamer will open the hole too large...others on the forum may have an idea or two but maybe use a long 1/4 bolt with the head cut off and cut a slot down one end, then fead a piece of emery tape into the slot with the tape wrapped around the bolt a couple of times and spin it in a hand drill. You can then a little at a time ease away the high spots down the hole, try keeping the tape from removing alloy at the mouth of the hole to prevent it bell mouthing too much......good luck....Greg.

 

[Grash]

Thanks guys, very good info. Vince998, I shall try your method for depth setting once I have scraped out the holes. In my first attempt ( I imagined they would just drop into place, duh), I had them both attached to the steady plate, with ET98/1s, and intended to push the plate down onto the spacers ET162, to set them at correct depth. Some misalignment may then have startd them at the wrong angle. Perhaps I should leave in the oven for longer too. I tried measuring the change in dims for the spindles having left them in the freezer overnight, but hardly detect any change. Looked up the temperature coefficient for steel (16 x 10^-6) and this would give a change of 0.2 thou if the freezer is at -10 deg C. Not much change but I guess it must slow down the temp rise as it's going in, which should help.
Off to bodge a scraper or I may try your micro sander, Greg. Watch out!
Thanks again, it really is comforting knowing there's someone up there listening!

Grash