Missing thread- tap + die procedures.

[Dan_F]

There used to be a thread in this forum (before the move) which specified hole size for tapping (7/16" ?) and size to turn tenon before threading with the die (no idea). Can anyone provide those measurements again? Thanks.

Dan

 

[DCBluesman]

Credit to Bruce Robbins.

The CAP
I drill the cap with a 7/16" drill for the male tap which I hold in a "Tee" handle and hand tap the threads. I tried putting it in a Jacobs chuck in the tailstock and hand turning the headstock but couldn't get the proper "forward thrust VS turn" down pat and ruined several threads. I squirt a little WD-40 on the tap and it cuts into the acrylics nicely. I simply look down and align the tap with a straight line on the lathe bed. If you find a better way be sure and share your success.

The bottom
I found that turning the blank down to .466 gives me a nice diameter to run the die up on, again being hand held in a die holder and a squirt of WD-40 allows for fine shavings to curl away. Once arriving at .466" and finding that it worked, I haven't experimented since so there could easily be a better diameter for the threads. Again, if you find a better way be sure and share your success.

I drill with a "Q" bit then tap the inside threads with a 10mm X 1mm tap first then screw in a dummy threaded rod I made from maple to strengthen and support the inner nib threads while threading the larger outer cap threads. The nib threads are sloppy but not any sloppier than the kit threads.

 

[LEAP]

http://www.penturners.org/forum/showthread.php?t=6700&highlight=thread+diameter&page=2

 

[LEAP]

Oh and Bruce if you read this try the tap in the drill chuck but with the tail stock free on the ways. A light pressure on the tailstock body as you turn the head stock and the tap walks itself right in.

 

[BRobbins629]

Oh and Bruce if you read this try the tap in the drill chuck but with the tail stock free on the ways. A light pressure on the tailstock body as you turn the head stock and the tap walks itself right in.

That's exactly what I do. Also have a die holder that fits the chuck.

 

[Dan_F]

Thanks so much guys!! I remember the thread that leap linked to, but thought that the older threads hadn't made it over yet, as there was no page count for this forum on the new server. Hope to have something to show before too long.

Lou---interesting procedure that is with the maple supporting the barrel while using the die.

Dan

 

[ldb2000]

Dan , also try using Pam cooking spray as a lubricant instead of the WD 40 , several people here have found that it does a better job of lubricating the tap and die and gives a cleaner thread .

 

[Dan_F]

Dan , also try using Pam cooking spray as a lubricant instead of the WD 40 , several people here have found that it does a better job of lubricating the tap and die and gives a cleaner thread .

I'll try that, only had time so far to do some practice inner threads, using WD 40 they look kind of rough.

Dan