Removing jointer knives

[Jim Terrill]

I got a Jet JJ-6CS off craigslist for $50 a few weeks ago, it had a few nicks in the knives, so I figured that I would order new ones. The jointer apparently had not been used in 10 years, so I would assume that the knives had not been removed in at least that long, based on the print date of the manual I would guess that the machine is probably about 15-20 years old and was barely used. I tried to remove the retaining bolts for the knives, but try as I might, some of them are really stuck there. I have tried liquid wrench, a regular wrench, needlenose vice grips, nothing has worked. I'm wondering if anyone has any ideas on anything else I can try. I can get replacement blade holders and such, so I'm not going to do anything that would damage the head, but if I can't figure out anything else, I think I may just have to use a dremel and cut off wheel to get these loose. I'm still way ahead compared to buying a new unit, but this has become fairly frustrating to say the least.

I was looking at global tool for replacement knives, but if anyone else knows of a good source for knives at a reasonable price, please let me know.

[lowell holmes]

I bought Frued jointer blades for my 6" Jet from Amazon. IIRC, they cost $22. This was a couple weeks ago.

[Tom Veatch]

Jim, are you taking about the hex socket head cap screws that go through the blade retainers? If so, they are probably rust frozen. The best "liquid wrench" I've found is called "Kroil". I've got an old grey-market tractor that spent most of it's life swimming around Japanese rice paddys, and Kroil or it's aerosol version "AeroKroil" has never failed to loosen the rusted and frozen bolts on it.

You may already know this, be even when you get the screws loose, it still takes some pretty good whacks on the inserts before they release the blades. One of the tools that came with my JJ-6 jointer was a brass dowel to use for that purpose. If you don't have a manual for the jointer, I'd suggest downloading one from the Jet website.

If you can get the blades out without damaging the head, that's great, but if not, I've still got the head that came out of my JJ-6 when I converted to a Shelix head and will make you a good deal on it. If you think you might be interested, PM me. I understand there have been two different diameter heads used on those jointers during their production life, so I'm not absolutely sure mine would be a replacement for yours.

[Jim Terrill]

Jim, are you taking about the hex socket head cap screws that go through the blade retainers? If so, they are probably rust frozen. The best "liquid wrench" I've found is called "Kroil". I've got an old grey-market tractor that spent most of it's life swimming around Japanese rice paddys, and Kroil or it's aerosol version "AeroKroil" has never failed to loosen the rusted and frozen bolts on it.

You may already know this, be even when you get the screws loose, it still takes some pretty good whacks on the inserts before they release the blades. One of the tools that came with my JJ-6 jointer was a brass dowel to use for that purpose. If you don't have a manual for the jointer, I'd suggest downloading one from the Jet website.

If you can get the blades out without damaging the head, that's great, but if not, I've still got the head that came out of my JJ-6 when I converted to a Shelix head and will make you a good deal on it. If you think you might be interested, PM me. I understand there have been two different diameter heads used on those jointers during their production life, so I'm not absolutely sure mine would be a replacement for yours.

Yep, the hex head bolts. I have the manual, but I didn't get any brass dowel with the machine. For $50 though, I'm not too mad about it, I can see about procuring some from some mech engineering friends. I'll try to find some of the Kroil and see if that helps, if not I suppose I will have to resort to cutting and brute force. I have wailed on those bolts hard enough that the machine was rocking back and forth and they didn't move, so I'm not too sure how it will work. I guess the good news is that the knife assembly can be mangled as much as needed to get it out and that the bolts don't go into the head.

[Charles Cannon]

Forgive me for asking but which way are you trying to turn the cap screw? The first time I changed the ones on my grizzly I started out trying to back the screw out of the holder, that was wrong. I had to screw them in to loosen the knives. Hopefully your smarter than I am.
Cannon

[Jim Terrill]

Forgive me for asking but which way are you trying to turn the cap screw? The first time I changed the ones on my grizzly I started out trying to back the screw out of the holder, that was wrong. I had to screw them in to loosen the knives. Hopefully your smarter than I am.
Cannon

To the right, I looked up how to do it before I touched anything. I did second guess myself a few times when I couldn't get them loose, but some did loosen. Maybe 2 out of the 4 screws on each knife I was able to loosen.

[Chip Lindley]

Wear Gloves, and use a rawhide mallet to *help* your wrench along (to the right!) A little extra advantage works wonders!! IF you should round over the hex cap screw heads, just replace them. Grizzly and Delta want $1.00 each, plus shipping! I buy a bag of grade 8 cap screws and grind off the top markings to make them smooth.

[Tom Veatch]

Jim, on second thought, ignore what I said about the brass dowel and the whacking required. That was on my planer-molder which used a slightly different blade retention setup. I don't recall any particular difficulty with the jointer in that regard.

[Jim Terrill]

Jim, on second thought, ignore what I said about the brass dowel and the whacking required. That was on my planer-molder which used a slightly different blade retention setup. I don't recall any particular difficulty with the jointer in that regard.

Well after 10+ years in once place, they may require some...encouragement... to come loose. I'll try that if I can't get it loose after getting the screws out.

[Brian Tymchak]

Jim,

I just recently read here on SMC about someone using heat (propane torch) to unfreeze bolts. I did a quick search but didn't come up with the thread. I think they were removing knives from a planer, or the head from a planer. I've never done this so I can't offer any practical advice. Sure wish I could come up with that thread for you though. I'll pass it on if I come across it.

Brian

[Ray Newman]

Apply some heat!

Usually the metal expansion and contraction will break the screw/bolt free.

Take a small butane/propane torch and heat ea. screw head. Then let cool and heat again.

It may take 2 - 3 applications for this work on really stubborn bolts/screws. Sometimes it will help to apply KROIL in between heating and let soak overnight. There isn't too much that KROIL will not penetrate, but you need to give it time to work.

[Brian Tymchak]

Jim,

I just recently read here on SMC about someone using heat (propane torch) to unfreeze bolts. I did a quick search but didn't come up with the thread. I think they were removing knives from a planer, or the head from a planer. I've never done this so I can't offer any practical advice. Sure wish I could come up with that thread for you though. I'll pass it on if I come across it.

Brian

Found it. The issue was actually about removing a stripped screw, but 5 or 6 responses in, someone explains how this works.

http://sawmillcreek.org/showthread.php?t=131877

[Jim Terrill]

Found it. The issue was actually about removing a stripped screw, but 5 or 6 responses in, someone explains how this works.

http://sawmillcreek.org/showthread.php?t=131877

Hmm, well that makes sense on face screwed bolts, but I think heating would just jam the bolts in harder since they can't expand longitudinally. Maybe heating and letting them cool would break the tension?

Does anyone have a local/chain store source for Kroil though? Liquid wrench has always been sufficient for me, so I have never looked for it.

[Myk Rian]

Does anyone have a local/chain store source for Kroil though? Liquid wrench has always been sufficient for me, so I have never looked for it.
PBblaster works too. Get it at an auto supply store.
Use heat on just the screws. One of those small butane torches does great.
Don't heat the part with Kroil or PBblaster on it, unless you like putting out fires.

[Josiah Bartlett]

Tighten the bolts that you were able to loosen back up, then try to loosen the stuck ones. This will expand the milled groove slightly and at least take some of the tension off.

[Ken Platt]

I found that in order to loosen bolts on the jointer blades that were overly tightened, I had to take the pressure off of them. As another post mentioned, retighten the bolts you loosened. Then, try to find something to tap into the groove in the cutterhead to put extra pressure on the knife so that the pressure will be off the bolts. For my jointer, a small piece of metal with a few feeler gauge pieces to get it just right, tapped into the groove in the cutterhead, let me loosen up the bolts.

I'd just about despaired before figuring this out. Hope it works for you.

Ken

[Jim Terrill]

Well I just tried using a propane torch and got nowhere. First I tightened up the bolts I could move, then heated it with a propane torch, kept the flame on the bolt for 10-15 minutes, let it cool, no dice. Only other thing I can think of is trying to use MAPP gas to heat it up more, really get the thing red hot, but it isn't looking too promising right now.

[Tom Welch]

If the bolts are froze/rusted use heat on the bolts. Trust me it is the only way to go. I work on oil rigs for a living and everything usually requires heat to break free. Just heat the bolts until they get really hot, and put the wrench to them. The heat wil do it.

[Van Huskey]

Well I just tried using a propane torch and got nowhere. First I tightened up the bolts I could move, then heated it with a propane torch, kept the flame on the bolt for 10-15 minutes, let it cool, no dice. Only other thing I can think of is trying to use MAPP gas to heat it up more, really get the thing red hot, but it isn't looking too promising right now.


I think the key might be as the last poster suggested get on them while they are still hot.

[William Addison]

I'd let it soak in Kroil for a couple of days and then use something like my 12V Bosch impact driver on it, I've had incredible luck using it to loosen seized bolts. Just don't drive it too hard because those things can break a surprisingly large bolt.

[Rick Lizek]

The stamped stock wrench is junk. If a new wrench doesn't work then the dremel with a cutoff wheel will work. Cutting partially through will take the pressure off and the gib screw will easily be loosened. Then replace the damaged screw with the proper ones. Have also loosened them with a cold chisel. Have done this many times on this application over the years as a machine tech.

[Danny Hamsley]

Google RustReaper. It is great stuff.

[Jason White]

I was going to suggest a propane torch, too. Just don't let things get too hot or you pull the temper out of the steel.

Jason


Jim,

I just recently read here on SMC about someone using heat (propane torch) to unfreeze bolts. I did a quick search but didn't come up with the thread. I think they were removing knives from a planer, or the head from a planer. I've never done this so I can't offer any practical advice. Sure wish I could come up with that thread for you though. I'll pass it on if I come across it.

Brian

[Jim Terrill]

Just an update, I ended up giving up and resorting to the Dremel with a cutoff wheel, cut partway through like felling a tree, whacked them a few times with a masonry chisel to loosen them, pulled the knives out, then the bars. Replaced the knives with freud knives and the bolts with ones purchased at my local hardware store. 4 hours of work for $20 knives, but the jointer cuts great now. If only I could say the same for my craigslist table saw, which I need to buy the PALS system for. So much for the projects I wanted to get done this weekend...