Problem removing knife bolts on old Delta 6" Jointer Model 37-190

[mark ahlenius]

Hi all,

I have an older Delta 6" jointer model 37-190 which I've been trying to change the knife blades on (first time doing so). I penetrating oil on the knife bolts but 4 of the screw heads are starting to strip with the 5/16" open end wrench I've been using. I first tried using an 8mm wrench but that wrench did stripped as well. I have loosened 8 of the 12 bolts but these last 4 have heads which are rounding over.

Besides the penetrating oil, I've also heated the bolts with a commercial heating gun, to no avail. i also filed a small grove in one of my 5/16" wrenches to help it to fit the hex head bolts easier, but that did not help.

Looking for any suggestions here to help. Pictures below of specifics

thank you,

'mark

521590521589521591

[Tom M King]

My first try would be a better quality wrench.

[Maurice Mcmurry]

PB Blaster penetrating oil works better than others I have tried. An electric heat gun isn't as effective as a torch. If you use a torch don't over heat. I have carefully whacked a sloppy wrench with a big cross peen hammer to tighten it up a bit. If and when you get them out replace the hex bolts with square head bolts. I have an old Delta 4 inch, it has square head bolts as does my Powermatic and all of the other jointers I have ever worked on.

[Warren Lake]

I buy undersize wrench and grind them out till they fit snug. Too often the supplied stuff has play in it.

[mark ahlenius]

Thanks Maurice, that’s exactly what I am using. Unfortunately the smell of it in the basement makes my wife sick.

[Steve Jenkins]

Another excellent penetrating oil is Kroil. Best I’ve found. Amazon has it.

[Maurice Mcmurry]

Thanks Maurice, that’s exactly what I am using. Unfortunately the smell of it in the basement makes my wife sick.

It is very stinky! I see some you tubers set it on fire. I wonder if that does anything more than increase the stink? I think the hex bolts are the problem.

[Bill Dufour]

Buy a better wrench. If you can not find a service wrench a tappet wrench should work. Or grind down a too thick wrench.
I do not know what that wrench looked like before but it is now damaging the bolt heads. Stop before you make it worse and impossible to remove the bolt heads except by grinding.
Bill D

[Bill Dufour]

Unless it was made in Brazil an old delta jointer will use USA size bolts.

[Joe Delfino]

It's been several years since I had to do this and I might be wrong but try loosening in the opposite direction. Something makes me think it was backwards from tightening and loosening a regular bolt.

[Maurice Mcmurry]

It's been several years since I had to do this and I might be wrong but try loosening in the opposite direction. Something makes me think it was backwards from tightening and loosening a regular bolt.

Good point. It is tighten to loosen with jointer knives. OP has gotten a few out so I assume he has stood on his head while looking at a clock like I always have to do to figure out which way to turn. My dyslexia is getting worse. I am starting to mix up W and M.

[mark ahlenius]

It's been several years since I had to do this and I might be wrong but try loosening in the opposite direction. Something makes me think it was backwards from tightening and loosening a regular bolt.

Hi, thanks for the reply Joe. I know I am turning the correct direction because the other 2 bolts loosened up that way on the blade. At first I was not sure because the instructions say to turn it clockwise, but they did not mention which direction you are looking at the bolt from. So i found a video and copied that direction and it was correct.

thanks

'mark

[Ken Platt]

I used to have that jointer and had the same problem. If you can take the pressure off the screws, you might be able to turn them then. Find a flat piece of metal that fits very tightly into the slot where the screws are, tap it in, (so that it, not the screws, are pushing against the knife) and it'll take the pressure off the screws and let you turn them. Yes, I'd stripped a couple heads while I figured this out. I used a piece of metal that I had laying around the shop that just happened to be the right size, but ideally you'd like something just a bit tapered, I suppose. Good luck.

Ken in North Granby, CT

[Cameron Wood]

Start with a decent wrench and grind it thinner to fit.

[Richard Coers]

Start tapping near a corner of the bolt with a pin punch in the direction of loosening. The impact cab often loosen them up.

[Kenneth Moar]

I recently had the same problem on my relatively new jointer. I didn't fool around with penetrating oil or heat, just took a mini hacksaw and cut the bolts , problem solved. Got replacement bolts from Amazon.

[Ronald Blue]

Here is a different option. Get a 5/16" flare nut wrench and grind the thickness until it will just slip into the opening available. Maybe with the extra contact available it won't be as prone to rounding off. Good luck.

[Maurice Mcmurry]

Here is a different option. Get a 5/16" flare nut wrench and grind the thickness until it will just slip into the opening available. Maybe with the extra contact available it won't be as prone to rounding off. Good luck.

Thats a good idea but only an open end wrench will go on. I do like flare nut and box wrenches. They don't work on jointer knives. My flare nut wrenches made a move from my plumbing tool kit to my mechanics tools a few years ago. They can save the day on some projects.

[Jerry Kitzhoffer]

I have the same model and had the same problem. I used a needle nose vice grips to get mine loose. Ordered some replacement nuts for those that got buggered up.

[mark ahlenius]

Yep I did try that as well. I ordered a micro butane torch and will try that today when it arrives to heat just the bolts.
I also filed a notch in the bottom of the 5/16” open end wrench so that it fits the hex head bolt a bit better. Hopefully something will work, otherwise if I can’t get it out, I may buy a Shelix head for it and be done with this old one.

thanks for your suggestions everyone!

[mark ahlenius]

I have the same model and had the same problem. I used a needle nose vice grips to get mine loose. Ordered some replacement nuts for those that got buggered up.

Where did you find a needle nose vice grip? I’ve looked around for one but all that I’ve seen have jaws which are way too thick for the less than 1/4” spacing

thanks mucn

’mark

[Cameron Wood]

I have some needle nose vicegrips, and have found them barely worth keeping around.

Can't imagine they would work where a decent end wrench wouldn't.

[Cary Falk]

http://https://www.homedepot.com/p/Stanley-6-1-2-in-Locking-Pliers-STHT84404/311349174 (https://www.homedepot.com/p/Stanley-6-1-2-in-Locking-Pliers-STHT84404/311349174)
Here is one. I have on from Lowes as well. I have never had much luck within because the thinner jaws flex/twist and come off the bolt. I had to remove a socket head cap screw out of a Jet planer moulder after the head stripped. I welded an allen wrench into the head and then used an impact wrench to get it out. I'm pretty sure the heat loosened it up. I would chase the holes wit a tap when you are done to clean out any rust when you are done. A little evapo rust wouldn't hurt if you goy it. Get all new bolts of the hardest grade you can find.

[Warren Lake]

how is it they got to be so tight? When changing knives its good to run the gibbs and bolts over a grinder with soft wire wheel to remove any the pitch and clean all up nicely. Maybe at one point i put them in a five gallon pail of reducer but not needed even Pine pitch comes off fine with the wire wheel. Then all goes back together clean. You are supposed to loosen them all in a few stages as well to keep a bit of a balance.

[mark ahlenius]

Hi Warren,
I have no idea. I’ve never removed them before, so this was factory tight. I guess years of light use and time just kind of froze a few of them in place.

Thanks for your suggestions

’mark

[mark ahlenius]

I recently had the same problem on my relatively new jointer. I didn't fool around with penetrating oil or heat, just took a mini hacksaw and cut the bolts , problem solved. Got replacement bolts from Amazon.

THanks Kenneth, well your approach is just what I did earlier this afternoon.
I’ve tried; penetrating oil, heat from a heat gun, a customized open end wrench, a mini-butane torch, a customized needle nose type vise grip, and finally I got out my Dremel multitool with a hardened bit and sawed through the last of the frozen bolts. Just placed an order for some replacement bolts (same size and weight) and waiting for those to come in.

Appreciate all the suggestions!

Solved for now!

’mark

[Maurice Mcmurry]

Square head gib screws (bolts) greatly reduce the chance of having the same problem again. This is my first time seeing hex head gib screws.

[Jerome Stanek]

Have you tried tightening them and then loosen them

[Cameron Wood]

Are you able to remove the cut-off bolts? There can't be much to grab on to...

[Tom M King]

Glad you were able to get it done. Does this one run 3/32" thick knives or 1/8"? My old 8" uses 3/32, and if you put 1/8 knives in it there is not enough room to get a good wrench on the screw heads. It also has square headed screws. In use I can't tell any difference between the quality of cut with either 3/32 or 1/8 knives in it. I ordered a set of 1/8" a long time ago before I realized it was best with 3/32. If someone put 1/8 knives in it when it was designed for 3/32, that might be part of your problem.

[Kenneth Moar]

Glad it worked out , you put in enough work!

[mark ahlenius]

Hi, thanks for the reply.
These are the OEM blades from Delta. I am the only owner of this machine and I’ve never changed them.
I did pick up a few 1/4-28 bolts at the hardware store to replace the damaged bolts, but they will be heavier than the other bolts (which were not damaged). This might cause the cutterhead to be unbalanced, So I’m going to wait for the OEM bolts I ordered from ereplacement parts

Mark

[Warren Lake]

most of the jointers ive seen have Hex bolts. The general is the only one with square.

[mark ahlenius]

Are you able to remove the cut-off bolts? There can't be much to grab on to...

Yes, they came out easily.

[Maurice Mcmurry]

most of the jointers ive seen have Hex bolts. The general is the only one with square.

How did I become a dinosaur at only 60? Traditional gib screws have square heads. Hex heads trying to pass off as gib screws is proof that the world is not getting better. Images to follow. If you have doubts, get out your saw or grinder and cut those hex heads off while they are down in the machine, (no thanks)!

Old(er) Delta = square ............Old Powermatic = square... more to come : )
521862 521863 521869
...521870......................521871 .....521872
another old(er) delta = square, Sears = square,------ Powermatic = square

.521873......521882
Davis and Wells = Square...Oliver = square, Foley Belsaw = Square, the list goes on.

[Ole Anderson]

Glad you got it done. For smaller stuck bolts, hex head or otherwise, I find a good socket with a 1/4" hex drive that fits a impact driver works, the rattle is just what is needed sometimes to loosen the bolt. To make sure I get a good grip, I will flatten the bit on a grinder to assure I get the maximum bite.

[Warren Lake]

the 8" General jointer is square. The 14" SCM machines are Hex. The 20 Griggio is square. The 24 Wadkin runs large allen head screws through the head so a totally different system. Half my machines are hex head. They dont determine anything about the machine.

Ive had no issues on any of them. The generals are small. All the other machines bots are over twice the size of the general.

[mark ahlenius]

Hi
I bought my machine back in ~1997 or so. Manual was printed in 1996. All 12 of the bolts in mine had Hex heads and the thread was 1/4-28.

If anyone does have a Delta 6” model 37-190, please give me a shout. I had to cut out several of the bolts in mine which were frozen and I had never moved the blades (light user). I bought 10 OEM replacement bolts from eReplacementParts.com and I almost needed to take a 2nd mortgage out for them (just kidding) but they were $5.10 each. But here’s my question, since I had all the bolts out, I am noticing that the threaded bars which hold the blades have a concave edge and its higher on one edge than the other. Just want to make sure I have them all back in the right direction. Would the higher edge go towards the blade? That’s my thinking.

thx

[mark ahlenius]

Thanks Warren!

[Tom M King]

Yes, higher edge towards the cutting edge of the knives.