PM 3520B Index Holes

[Mike Goetzke]

I've had this lathe little over a year now and just noticed the 3 or 4 threaded index holes on the head stock are open and not plugged when not needed. Seems like over time debris could accumulate in this cavity? Anyone see the need to cover these up?

Thanks

[Roger Chandler]

No......not necessary. I know numerous 3520b owners, and none of them have the holes covered on their lathes.

[Jon Nuckles]

I have wondered about that myself, but have never covered mine and have never had a problem. I rarely use the index holes, but I do blow them out with compressed air if I notice anything stuck inside.

[Mike Goetzke]

Thanks - I'll just leave them alone.

Mike

[Joe Kaufman]

I immediately installed set screws to keep debris out of the bearing area. The two bearings at the spindle nose are shielded not sealed.
I don't used compressed air for the same reason. In spite of the effort, I still had one bearing that developed a noise after a year and a half.

Joe

[Jeffrey J Smith]

In spite of the effort, I still had one bearing that developed a noise after a year and a half. Joe
Joe - I've only rarely heard of a 3520B having bearing problems after 18 months - could it have been because of the effort? ;>)

[Thomas Canfield]

No......not necessary. I know numerous 3520b owners, and none of them have the holes covered on their lathes.

I have installed some socket head drive screws (low head profile) in mine and furnished to other club members to plug the holes. I purposely avoided set screws without a head to prevent possibility of screw working into the lock position and damaging the shaft.

[Mike Goetzke]

I have installed some socket head drive screws (low head profile) in mine and furnished to other club members to plug the holes. I purposely avoided set screws without a head to prevent possibility of screw working into the lock position and damaging the shaft.

Happen to know thread size?

Thanks

[Joe Kaufman]

The thread size is 5/16-18. I used 3/8 long Stainless Steel set screws. There is enough resistance that the don't move by themselves.
You could lightly deform a thread if they move.
I suspect one of the original bearings had a problem as I started noticing a slight noise after a couple of months use. It progressed to a point where it was an annoyance to me. PM sent new bearings that were made in China. The original were Taiwan and had a nicer external finish than the China ones. I purchased bearings for replacement.

[Doug W Swanson]

I got tired of cleaning out the holes so I just cut up an old motorcycle tube and use that to keep the gunk out. Works great!

[Alan Heffernan]

I got tired of cleaning out the holes so I just cut up an old motorcycle tube and use that to keep the gunk out. Works great!

Nice solution that I will replicate! I have some motorcycle tube in the stash for such things.

[John K Jordan]

My jet lathes have the same holes and have never clogged.

The only time I use them is to lock the spindle while carving. I found them such a pain to use I bought a good indexing wheel instead.

JKJ

[Phil Warnement]

I just put a piece of tape over them.