TBC Questions

[mgoetzke]

I purchased a PSI TBC system. I've turned maybe 8 pens now. I noticed the headstock end is usually pretty well centered but now that I'm more observant I can see the tail stock side in some cases is not perfectly centered (some turned blanks are perfectly centered and some are not).

Ha - then I made the mistake of measuring things. The headstock has zero runout. The rotating center is 0.002" to 0.003" out, the ID of the bushing is about 0.004" smaller than the mandrel OD, and the tube ID is about 0.004" larger than the bushing. Worse case I could be 0.011" off!

Do others try to adjust the runout on the tailstock end first?

I also see some actually just turn between centers without bushings and measure the ends - is this the best solution?

Thanks
Mike

 

[rherrell]

"Ha - then I made the mistake of measuring things." NEVER a bad idea!!!

IMO .004" difference between the bushing and the tube is excessive. There are folks on this forum that sell bushings so I'm sure someone will let you know who they are. I would start there , with new bushings.

I've never used the PSI system but if your numbers are correct it's not a quality item. Like I said, buy AMERICAN from one of the bushing vendors on this forum.

 

[RichAldrich]

Same for me. No run out on the headstock piece. Tail stock piece is junk. Using my 60 degree live center on the tail stock.

I purchased tbc bushings from Exotic Blanks for the JR. Gents. They work with a 60 dead center and 60 live center. Not sure what all models they offer. Easy to deal with and the M&M's are great.

 

[mmayo]

IMO - junk the PSI system, eat the cost.

Now buy REAL TBC bushings from Nikitas. Everything will be perfect if your lathe is true. To check, install two dead centers and see if they touch perfectly. Adjust until they do.

Never look back.