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Posted: Sun Dec 12, 2010 6:25 pm
by JPG
hfmann wrote:Ok....working on this jig today. I've got the hold drilled for the 1/4" hex head bolt that will mount the dial indicators. I've got the base cut for the magnet. I'm ready to drill holes in the 1/2 " sq tubing, but don't know what size to drill for the #8 wood screws. I don't have a huge asssortment of drill bit sizes available.
Are the metal tubes meant to freely rotate up and down? If so, and I drill the hole too big, won't the metal tubes have too much play to get accurate and consistent measurements on the dial indicator? If the #8 screw fits too tight, the metal tubes won't be free enough to rotate when adjusting the screws on the jointer blades.
What is just right? How loose should the metal tubes be
Thanks.
Hal
Loose enough to rotate freely under their own weight.
Tight enough to not wobble while doing so.
Since the square tube needs to 'self align' to the blade, some slop is needed if only to compensate for the lack of precise positioning(angle) of the screw(pivot). We can assume the blade will be 'square' to the bottom when set properly.
Posted: Sun Dec 12, 2010 8:03 pm
by hfmann
Thanks JPG - make sense to me.
Hal
Re: Nick's knife jig
Posted: Thu Feb 17, 2022 10:38 am
by hfmann
Can't believe it's been 12 years since I built Nick's jig and only now trying to use. It just seems like a terrific "foolproof" jig. Well dang me. I set my knives and wow they were big time off. I found my steel tubes weren't absolutely flat on the outfeed table allowing them to tilt slightly down at the knife point. Using a feeler gauge I found mine are above the table by .009 at the pivot point. Any thoughts about how I might go about fixing this?
I've tried the standard steel ruler 1/8" drag technique so many times I've got no hair left (although I didn't start with much

. But maybe Bill Mayo's careful description just means I've got to get a whole boatload of patience and keep trying over and over until I get the feel.
thanks all,
hal

- bottom of steel tube at pivot is .009 above the bottom
- 2022-02-14 12.55.54 resized.jpg (180.2 KiB) Viewed 791 times
Re: Nick's knife jig
Posted: Thu Feb 17, 2022 11:52 am
by DLB
(Full disclosure: First time I've seen this, and I did not watch the video.) Looks like your round-over on the metal tube or bar is on the top but should be on the bottom. Is it possible you created the 0.009" error by inverting and/or interchanging the bars? If not, and IIWM, I think I would just re-drill the hinge holes a little farther back from the knives location. Because IMO it would be best if the dial indicators were directly above the knives anyway, so that whatever they are indicating is the actual knife offset above the outfeed table. I don't see any advantage of having the metal arms extending as far past the indicators as shown.
I like the BM method. Sounds the same as what I've done in the past with the addition of the lock washers, which sound like an improvement.
- David
Re: Nick's knife jig
Posted: Thu Feb 17, 2022 2:31 pm
by hfmann
Hey David,
Looks like your round-over on the metal tube or bar is on the top but should be on the bottom. Is it possible you created the 0.009" error by inverting and/or interchanging the bars?
What a great observation. I';ll check that out right away.
Also love your idea of just moving the arms back some and drilling a new hole. I was way overthinking how to reattach them.
thanks much - I'll report back.
hal
Re: Nick's knife jig
Posted: Tue Mar 01, 2022 1:50 pm
by hfmann
Update: FIXED.
Turned out that when I snugged the tubes to the body they got pulled up a smidgeon. When I loosened them they sat flat and the whole device worked tremendously. Easily got all the blades to .001. Sweet.
Test jointing passes on a pretty ragged edge proved all seemed to working fine
HOORAY!
now to do some woodworking
thanks all,
hal