JET BD-920N Face Plate Mounting Problems

[PeteCronos]

I am having a problem with face plates for my lathe.
I have purchased 3 face plates, two from the same vendor (one of these two fit).
One fits the lathe and the other two will not. The two that will not fit thread about half way on
and then that is as far as they will go. It appears that there is a thread problem.
It doesn't appear to be the lathe spindle since I have a few chucks that came with the lathe
that fit just fine. These are not expensive face plates but do cost a fair amount.
Any suggestions appreciated.
Also I could use a 5" face plate and maybe a smaller one also.
The thread for this lathe is 1 1/2"x 8.

 

[Ulma Doctor]

get a 1-1/2"-8 tpi Tap, and run it through the bore
you could also make a 1-1/2"-8 tap too, if you had the inclination or desire.
since you'll only likely use it a couple times and are going to use it on cast iron, you could get away with softer steels
good luck in either event!

 

[PeteCronos]

The problem is that a USA made tap 1 1/2-8 will move free thru the face plate that is giving problems.
I have 3 other face plates and the tap seems to go thru them the same as the one that will not
mount on the lathe.
The problem face plates screws on and gets tight before it is on completely. Just like the thread
has a taper. Not sure what the problem is.

 

[pdentrem]

Is there an unthreaded section just before the face on the spindle? Just thinking that the threads stop early and there is no clearance on the face plate to allow full engagement. I know that on my Jet BDB-1340 clone the threads on the spindle stop before the face. The back plates that I made, had to have a unthreaded area at the rear. Check the picture in my post that shows the spindle plug that I made to qualify the threads on the two plates. It shows the area that is not threaded.

http://www.hobby-machinist.com/thre...ed-spindle-backing-plates-for-my-lathe.19802/

Pierre