removing a tailstock taper

[Andy T]

(05-20-2017, 05:14 AM)Mayhem Wrote: Thanks for the pics Andy - for me that has confirmed my thoughts and I think the best option would be to have someone drill a hole through the bore from the blind end.

Thanks for the reply Mayhem, the overall length of the quill is 13" ( 1 1/8" OD ) with the blind taper hole at aprox 3" deep, so a 10" hole to drill.
I have some 10mm long reach drills but can only drill to a depth of 8" with them, If I do the job myself I'll put my ER32 collet chuck in the 3 jaw lathe chuck and the 10mm drill in the collett chuck but would have to drill from both ends of the tailstock quill.
Got to get the lathe powered first though and have some parts arriving next week to start making the layshaft, I'll keep you all posted on the progress.
Thanks to all for the responce so far

[awemawson]

Twist drills are easily extended by silver soldering an extension on the end. Turn the gripping end of the drill down to a suitable diameter to be an easy slide fit into the end of your extension. Pop a bit of flux and silver solder in the hole followed by the drill spigot and gently bring up to heat. (If the fit is too tight the drill will pop out of the hole when you heat !) The non drilling end of twist drills is left soft in manufacture.

[TomG]

That's a new one on me as well. Never seen a quill without a through hole for the screw.

Tom

[Mayhem]

If you move the tailstock to the chuck side of the carriage, you can drill the hole using the power feed (i.e. use the carriage to push the tailstock toward the drill. Depending upon the alignment of your tailstock to the ways, you may be able to flip it around and drill from both sides. It will depend on the configuration of the ways and whether they are symmetrical.

[Andy T]

(05-20-2017, 09:35 AM)Mayhem Wrote: If you move the tailstock to the chuck side of the carriage, you can drill the hole using the power feed (i.e. use the carriage to push the tailstock toward the drill.  Depending upon the alignment of your tailstock to the ways, you may be able to flip it around and drill from both sides.  It will depend on the configuration of the ways and whether they are symmetrical.

An excellent idea, I'll need to get or make some change gears first though.
I spent a fair bit of time the last few days back engineering the 1 change gear I have to find the diametral pitch and found it is 16, then used the information on the name plate to work out all the gear size blanks I need. Looks like an easy set up to cut the gears on the lathe with the gear cutter on a mandrel between centers. Just need to get my head around pressure angles to make sure I have that part right.
Reading up on information on the web it seems all kinds of materials can be used to make the gears and for practice and possible use I might make the first few from solid polycarbonate. I've worked in the plastics industry machining this material before so it should be ok.

[awemawson]

There is an easy way to check a gears pressure angle:

Pressure angle is the flank angle of the rack that the gear engages with so we need a rack to measure - take some child's Plasticine or modelling clay - form a long flat surface and roll the gear on it to make a nice impression. With a very sharp knife and ruler cut the clay along the formed rack so that you can look at it's profile sideways. With a school transparent protractor you can easily see the difference between 20 PA and 14.5 PA