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Threading issue

ohiomuse

Plastic
Joined
Jan 20, 2020
Newbie to the forum. If I've posted this in the wrong place, let me know.

I managed to horse up an adjustable, studed handle on my 20 year old Delta jointer and am attempting to replace/repair it. The stud on the handle threads into a cast iron (I presume, perhaps it's ductile, I'm certainly no machinist)plate. Of course Delta no longer has a replacement part available.

I can work around the problem with a pair of pliers on the stud, but that "just ain't right."

The OEM stud is, by my reconning an M6 X 1 thread (it threads cleanly into an M6 nut, with no noticable slop at all). I first tried a M6 X 1 cap screw thinking that would work, but it snugs up pretty tightly (by hand) about three turns in. Didn't want to force it beyond that point.

So, I figured the threads in the plate may be buggered up a bit (tho' there's reason to think that they are - the OEM stud threads through just fine) and trundled off the the hardware to get an M6 X 1 tap to chase the threads in the cast. Same thing, except this seemed to tighten up just about the time the threads started wanting to cut. With the plate being cast (it's maybe 5/8 in thick and the screw hole is about 3/16th from a corner on the plate,) I didn't want to put any torque other than my hand on it for fear of really making a mess. The hole is through and through.

Soooo. off to McMaster Carr for a replacement adjustable handle in M6 X 1. Same story. Darned nice handle tho - much nicer than the OEM one.

FWIW, yes I've tried Imperial screws in the hole as well - everything's either too small to bite at all, or too large to even start in the hole.

Thoughts? What will I run into / need to look out for if I seriously try to run that tap (it's nothing special - just a run of the mill Irwin tap from Ace Hdwe) into that cast? Obviously I don't want to break the tap in the hole, nor do I want to stress the plate to the point with the tap that it cracks. I haven't pulled the plate off the machine to see if anything will thread through from the other side... it looks like that might introduce a need to do some setup work on the jointer I'd rather avoid.

Any and all comments welcome.
 
It would help if you could tell us which model Delta jointer you have,and where the handle you're referring to is located. Is it the table adjustment lever?
Rick W
 
1/4-28 maybe??? It's awful close to M6x1, mistaking the two would probably cause exactly what you're describing. I would expect an older American woodworking machine to be Imperial. Is everything else on the machine metric?
 
Thanks, fellas.

RE: Jointer model - Delta 37-866X, Type 1, S/N 011016 W3031. The Delta P/N I'm replacing is 1346751. (Shown as part no. 19 on schematics. "Lock Lever Assembly")

RE: 1/4 - 28 - Well, I (perhaps too quickly) dismissed that since the stud didn't mesh well with my thread guage at 28 tpi. And in honesty, I didn't think "fine thread" for a 1/4 stud. I should have but I don't see a lot of fine threads day-to-day and that possibility slipped my (old) mind. Easy enough to check, so off to the hardware to get a fine threaded 1/4 inch bolt to check against. FWIW, the machine is China made... so, well, my head just didn't come back around to Imperial right away.

RE: High performance tap... I've read a little bit about the differences, and you've helped there too. Firms up some of what I've read about tapping iron. From what I'm reading it looks like hand tapping would be pretty difficult especially with the plate mounted. If I end up going that route, I'm probably get someone who has some idea of what they're doing take care of it for me.

Thanks again - I'll let y'all know how this turns out. My hope right now is that it's a quarter-inch fine threaded stud.
 
I'll keep this short. After trying a fine thread 1/4 bolt in the plate and a 28tpi tap, that still didn't get me there, I decided I was getting close to the point I might have to have the plate tapped by a pro, so I pulled the plate from the base.

The M6-1 stud spun right into the plate from the back and only got a bit snug on the last couple of threads (which were on the face of the plate). I was able to hand spin through those threads, chasing them out cleanly with a SS bolt.

And, I don't believe I'm going to have any setup issues with the infeed table either.

So, at least on my Delta P/N 1346751, the stud is an M6-1 thread.

Thanks again, everyone!
 
If you need to replace the "lock lever assembly", those are available from a number of sources such as McMaster, Enco, Essentra, etc. Look for a "Locking Lever" or "Adjustable Handle" with the proper size stud.
Rick W
 








 
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