Problem With PM1340GT Compound Base Lock.

[bretthl]

Could you put the T Nut back in the slot and then make a plug to go into the entry hole? It would do nothing for making the T-Nuts stronger but it would keep them from falling out. It would save taking the cross slide off.

Just a thought

Roger L

Ah! I just saw this and will work it. That will save me time, precious time. Thanks.

 

[bretthl]

Could you put the T Nut back in the slot and then make a plug to go into the entry hole? It would do nothing for making the T-Nuts stronger but it would keep them from falling out. It would save taking the cross slide off.

Just a thought

Roger L

This will get me by, not much T-nut engagement. Thanks.

 

[Stonebriar]

I wonder what the max size T-nut could be made to fit in there is. You are right that is not much holding power

 

[dpb]

You can’t make a meaningfully larger t-nut, and still insert it using the factory entry slot. If you make an entry hole in the back, you solve this problem. Photo shows original, and replacement t-nuts. A replacement nut is shown, installed in the 30° location, with plenty of contact.

 

[Firstgear]

I went to cut an external thread, set the compound at 29.5 degrees and one of the bolts would not tighten. Removed the compound without rotating and low and behold the lock nut is positioned exactly at the insertion point. Any ideas how to fix this? This just happened, I have cut many threads with the compound at this position. It is to the point where I can no longer lock the compound base anywhere near 29.5 +/- 2 degrees.

View attachment 301548

I had a problem with my 1440GS, the lock nut wouldn’t tighten after tightening it up about a dozen times. Turned out that it could easily be stripped because of how it was made. I called PM and got exactly the same parts that the machine came with. I ended up making my own locknut, now all is good.

 

[Stonebriar]

This looks like a project for my list of upgrades to my PM1440GT.

 

[petertha]

I have a Taiwan 14x40 lathe with a similar T-nut retention system. It has some additional irritating attributes. 1) A nut can partially get bridged in the casting hole 2) the nuts can get themselves out alignment relative to the compound bolt holes & then you spend 5 minutes playing hide & seek. I made these makeshift spacers out of wood just to see if it would work. 10 years later they are still there, just a bit oilier

 

[bretthl]

Slight improvement to the access hole plug. Seems to work better. Careful to ensure plug dimensions were exact.

 

[dpb]

Slight improvement to the access hole plug. Seems to work better. Careful to ensure plug dimensions were exact.

Out of curiosity, how did you make that plug? I can think of a couple ways, but they don’t seem to match the tool marks I see.

 

[bretthl]

Out of curiosity, how did you make that plug? I can think of a couple ways, but they don’t seem to match the tool marks I see.

It is pretty rough but I was moving fast to get it done. I used a super spacer on the mill and a 1/2" end mill. With a 1" 1018 round mounted horizontal in the chuck I cut the key coming in from the end of the round. Then I rotated the chuck and removed the remainder of the material down to 0.740" OD with the 1/2" end mill then switched to 1/4" closer to the key. Parted off with the lathe and faced the end oposite the key to final length. Thanks for the plug idea!