Perhaps this will help someone.
Of all the Nova chucks and inserts I have, one one didn't run true when checked with a dial indicator, even after the normal procedure to check for burrs or debris on the insert and the chuck. The "wobble" was very slight and might be acceptable for some but not for me. This was tested with a new SN2 chuck. I mounted that chuck on a different insert and it was fine. Put the bad insert on the shelf and forgot about until I bought another new SN2 chuck a couple of days ago, this one with no insert.
Instead of returning the bad insert and waiting for a new insert I decided to fix it.
Note there are other ways and reasons to true up steel on the wood lathe using woodturning tools- I once turned down some Nova pin jaws for a special purpose using a woodturning HSS scraper. It wasn't quick or fun but it did the job.
Perhaps this might help someone with a too-wobbly chuck. Or offer it for fire-sale prices and maybe I'll buy, test, fix and donate it to a good cause.
Sorry, I didn't take pictures. A few pics could have clearly showed the process and shortened this long post.
JKJ.
Of all the Nova chucks and inserts I have, one one didn't run true when checked with a dial indicator, even after the normal procedure to check for burrs or debris on the insert and the chuck. The "wobble" was very slight and might be acceptable for some but not for me. This was tested with a new SN2 chuck. I mounted that chuck on a different insert and it was fine. Put the bad insert on the shelf and forgot about until I bought another new SN2 chuck a couple of days ago, this one with no insert.
Message #14 in this thread from a few months ago described the problem, and messge #23 described the next step which I finally got around to.
Instead of returning the bad insert and waiting for a new insert I decided to fix it.
- Testing was on a surface plate with a dial test indicator and by fastening the 1-1/4"x8 insert to the PM forwards and backwards. This proved that both ends of the insert were a tiny bit out of parallel. Further testing showed the surface that seated against the inside of the chuck was the problem.
- I fixed it quickly by truing the non-parallel end with a carbide cutter from my metal lathe. I couldn't do this on the metal lathe since I had no quick means to mount the insert (there are other ways to mount an insert or even the chuck body for machining but are "fiddly" and take some setup time.
- Truing the insert on the wood lathe was quick and easy.
- My triangular carbide insert cutters are mounted in steel bars to fit the tool holder on the metal lathe. Since I didn't have a good way to secure the bar on the PM I put a flat top box rest in the banjo and held the cutter bar flat against the rest by hand. By limiting the cut to just the point of the cutter, I was able to move the cutter by hand and true up the bad end a tiny shaving at a time. (using the flat of the cutter wouldn't work without a rigidly constrained cutter) With the end of the insert and the bevel running true, a diamond hone plate held flat against the end and the bevel smoothed things nicely. Remounted the insert in the chuck and all was well. This chuck now runs true well under 0.001", closer to 0.0005" like my most of my other Nova SN2 chucks.
Note there are other ways and reasons to true up steel on the wood lathe using woodturning tools- I once turned down some Nova pin jaws for a special purpose using a woodturning HSS scraper. It wasn't quick or fun but it did the job.
Perhaps this might help someone with a too-wobbly chuck. Or offer it for fire-sale prices and maybe I'll buy, test, fix and donate it to a good cause.
Sorry, I didn't take pictures. A few pics could have clearly showed the process and shortened this long post.
JKJ.
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