tightening gibs

[Rusty Eads]

I recently upgraded from a lunchbox planer with indexing knives to a "real" planer, a Belsaw 12" 9103. I have never had to set knives before so the question I have is how tight to tighten the gibs or can you overtighten them?

On a related note, when I removed one of the gibs there were strips of a pepsi can behind the gib, kind of like shims. Is there any particular reason for these? There are 9 gibs total on this planer (3 per knife) and it was only behind 2 of them. Any thoughts on these?

[Rusty Eads]

Well I figured I would just tighten them as tight as I can. Rather overtighten than have knives flying at me.

[Tom Esh]

I suppose if you really got carried away you could strip the gib threads. Otherwise I don't think there's much danger of denting the head.:D

Only reason I can think of for the shims might be to prevent the bolt heads or gib from shifting (and fouling up your setting) as they're tightened. It's definitely annoying when it happens.

[Chip Lindley]

Rusty, reason for the aluminum shim could be roughness in that area which caused the knife to shift while trying to set it. If jib bolts are over-tightened time after time, that area of the cutterhead contacted may be dimpled or chewed up. See if the locations under the "Pepsi can" shim are rougher than others. Could be the bolt heads themselves are chewed up, and the aluminum was used to protect the cutterhead. Either way, over-tightening can damage a cutterhead. Problems with knife setting are one thing; a cracked cutterhead is quite another!

When setting knives on my machines, I have always related the procedure to tightening lug nuts on a tire. I go around the cutterhead tightening each bolt three or more times, using a criss-cross pattern. Especially important if all knives have been removed. There is much more flex in a cutterhead than might be imagined.

I tighten each jib bolt until all will not tighten further with decent force. One must develop a feel for it. There can always be too much torque applied. These are relatively small bolts, and the bolt heads will be rounded over if too much force is applied. Horror of horrors, a bolt head could be broken off! Wear gloves; protect your hands. Lacerations happen in a split second!

[Don Jarvie]

Double check the size of the knives. They may not be the correct width and the previous owner shimed them to make them fit.

Look at the manual and check the knives you have to the size in the manual.

I don't see the need for shims. I had to literally pound my old knives out they were stuck in so good and that was after I removed all of the gib screws.

[Rusty Eads]

The knives are correct, none of the other 8 gibs had shims behind them. I did notice some swirl marks made by a grinder of some sort where the shims were. These marks look like they were made at the factory when the cutter head was formed. Not sure if that has anything to do with it. I don't think that it will affect operation at any rate. As for breaking the heads off the bolts, I don't have to worry about that as they are allen set screws so no heads to break off.

I am just a few days away from finishing the electric so I can finally run this bad boy. I will know for sure whether or not those shims were in there for a reason :rolleyes:

[Ryan Hellmer]

I don't know the reason for the shims, but I don't like the sound of all those gibs. The Foley was designed as a planer/molder so that's probably why there are multiple gibs per knife, to accomodate narrower molding knives. I would call woodmaster, the successor to Foley-Belsaw planers, and see if you can't get one piece gibs for that head. It would certainly make your setup and removal easier and would likely be much safer. Throwing knives/gibs is serious business (moreso on a jointer, but still).

Ryan

[Rusty Eads]

The middle gib is designed to hold the 1" molding knives so you can plane and mold all in one pass. I am sure that I could find 1 piece gibs for when I am not using the molding knives.

[Chip Lindley]

The knives are correct, none of the other 8 gibs had shims behind them. I did notice some swirl marks made by a grinder of some sort where the shims were. These marks look like they were made at the factory when the cutter head was formed. Not sure if that has anything to do with it. I don't think that it will affect operation at any rate. As for breaking the heads off the bolts, I don't have to worry about that as they are allen set screws so no heads to break off.


Oops, I forgot. Belsaw/Sears/RBI/Woodmster uses those type gibs. The big set screws travel vertically in the gib to raise it and wedge against the knife. Conventional gib bolts are horizontal and the head contacts the side of the gib slot, pushing the gib against the knife.

So, your cutterhead is in good shape with no distortions or marks. Great! I would ditch the aluminum shim, and treat all gib screws equally. Doubtful it was used to "balance" the cutterhead! LOL

Concerning tightening gib bolts, (allen set screws) those should all be tightened to the same torque setting. Without a torque wrench, your own judgement will be required. Those gibs are aluminum, so won't enjoy much over-tightening. I have never encountered one-piece gibs for a BelSaw, et.al. The 3-gib-per-slot arrangement is only a minor inconvenience; I don't see a problem. Concern for throwing a knife is really overdone! Unless the gib screws are VERY loose, dilligent effort used to tighten them makes safety not a factor.

[Rusty Eads]

Thanks Chip for your help and knowledge. I just realized that I am only 90 miles from you and we have actually met, talk about a small world.

Again thanks for the info and I will let everyone know my progress on setting up my first "real" machine

[Don Jarvie]

Careful not to overtighten. I did over tighten and I heard a crack. I decided to leave it be and worry about it when I change the knives.

Parts are still available through Belsaw if you ever need them.