I have an aged (~15 yrs) nova chuck. It's 4" in diameter and has a 1" x 8tpi thread pattern. One of the locations where you put in a screw to attach one of the jaws has become stripped. I contacted Technatool and they sent me a replacement, but it is not for this older chuck. When I let them know that the replacement doesn't work they said the chuck is so old they don't make it anymore and would not have any parts. I'm looking for some ideas to resurrect this still very viable chuck. Do you suppose someone has a similar situation and would have parts? I could take it to a machine shop and have the stripped hole filled and retapped? Could be somewhat costly but compared to a new chuck purchase might be worthwhile.
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Nova chuck question
- Thread starter Finn Posner
- Start date
You could repair the threads yourself with a product called heli-coil. The kit will have the tap, and I think the drill bit also. The stripped hole is drilled out then threaded for the insert, which is a wire coil, like a spring. An install tool (supplied) lets you thread the insert in. You can trim for depth and you’re all set. Doesn’t require special tools and is a great permanent repair.
Thanks Marc I'll have to look that up
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Yup, what Marc said - Helicoil - If you do not want to buy the kit (which typically includes the tap, an installation tool, and a dozen inserts, but no drill bit) , you can also check around at local auto repair shops and small engine repair shops. When I was in the business full time, I had a kit for just about every size in standard and metric that we commonly came across, including 14mm spark plug repair kits (10,8,6,5,4 mm kits and 1/2, 7/16, 3/8, 5/16, 1/4, 10-24, 10-32, 8-32 Imperial sizes) Most well equipped chainsaw shops probably have heli coil kits on hand (or the techs have them in their toolboxes) - stripping threads in aluminum parts was not at all uncommon thing...
+1 for the heli-coil. They work great, and the material that Teknatool uses for the slides will machine very easily.
I would tap it out for the next biggest screw size and use a bigger screw. Even though the bigger screw may not fit flush to the top of the jaw you should never have the piece you're turning touching the bottom anyway.
2 good approaches to deal with the problem. My approach would be in steps - I think the helicoil requires a larger hole vs the next larger screw (lookup hole sizes). Try the next larger screw, if not satisfied then go the helicoil route. Also research what it will cost to get a few larger screws (always want spares for the disappearing screws), they may end up costing as much as the helicoil kit by the time shipping is paid.
Food for thought. Drilling and trapping might be the most convenient and least aggravating route today. Then tomorrow you will have two sizes of screws to contend with and possibly two sizes of wrenches. Your aggravation level might go up exponentially. Just a thought ,good luck
Was the screw and the hole both striped? It might be possible to chase the female threads enough to make them work with a good threaded screw but you would have to find the proper metric tap to do it.
That was my only reservation with the drill and re-tap option, but if in a hurry to get the current job done and no heli-coil kit is readily available then needs must. Most local hardware shops at least carry taps.
Did you try to simply rethread the hole. M3 or m4 tap