Frozen TS arbor - Bosch 4000

[Richard Dooling]

I have a frozen blade lock nut on my Bosch 4000 saw. I had the saw jam on a work piece and that apparently screwed the nut down tight. I have now rounded over the arbor locking lever.
Any suggestions other than to buy a cabinet saw?:confused:

[Alfred Hoffmann]

The same thing happened to me about a couple of months ago. I had to use a pipe wrench and hammer to unlock the nut. Luckily it did not bent the shaft or ruin the thread. I added a 5/8" flat washer because the machined washer did show some grooves. I have had no problems since. I have since bought a replacement nut from eReplacementparts.com (P/N 248755). It's not a standard 5/8 - 16 threaded nut.

[Alfred Hoffmann]

Richard, I gave you the wrong part number for the arbor nut. The right part number is 2610358858. You can find the parts schematic and all replacement parts for the Bosch 4000 at: http://www.ereplacementparts.com/bosch-4000-0601476139-table-saw-parts-c-128_167_168.html. Good luck.

Al

[John Coloccia]

Can you get in there with an impact wrench? I've had good luck releasing nuts like this by taking the "wrong" size impact socket, and hammering it on the nut. I think what I've done is used a metric 16pt on a standard nut, if I remember right. The impact wrench is nice because you're not putting any bending force on the arbor. You may strip it worse, but you might do that with other methods anyway. I believe there exist sockets designed for removing stripped nuts, but I don't think they work if it's a reverse thread. I'm assuming the arbor is a left handed thread (i.e. reversed).

It's just what's worked for me. I'm sure there's a more professional way of doing it that assures success, but I dont know what it is! :)

[Richard Dooling]

Thanks guys. On the advise of a friend I'm going to heat the nut/arbor with a torch - just enough to get it good and hot - then flood it with ice water. Makes sense as a way to break the bond between the parts.

Dang, this was not supposed to be part of this weekend.:mad:

[Scott T Smith]

Richard, is that a reverse thread on that nut?

Re heating and chilling, be careful that you don't heat it so much that you ruin the bearings and seals on the arbor.

If it were me, rather than chilling with ice water, I'd have a towell in a bucket of water nearby, heat the nut with quickly an acytelene cutting torch (for concentrated heat, as the use of a rosebud would put out more heat but over a wider area), and try to back the nut off a few turns while it was still hot, then use the wet rag to cool down the arbor (it may steam up on you so be prepared to wipe, dip, wipe, dip, etc).

The objective is to get the nut loosened and then the arbor cooled before too much heat can transfer through it into the bearings and seals.

[Myk Rian]

Other than using water, a can of freeze spray would work.

[Richard Dooling]

Got it!! What a PITA though.

Had to hacksaw off the machine screws holding the arbor locking mechanism so I could shift that out of the way enough to get a crescent wrench on the motor side of the arbor. Still too tight though so I had to grind the wrench down to make it thin enough to fit.

Apparently heating and chilling the arbor/nut had helped because once I got a good fit on the arbor the nut came off - not easily but it came off. The nut is pretty torn up but at least I don’t have to take the saw apart.

Thanks for the advice.

[Jacob Reverb]

Apparently heating and chilling the arbor/nut had helped because once I got a good fit on the arbor the nut came off - not easily but it came off. The nut is pretty torn up but at least I don’t have to take the saw apart.

That heating and quenching business would scare the heck out of me on a saw. :eek:

You do know that heating and quenching steel is a good way to make it so hard that it becomes brittle and can break/shatter upon sudden strain or impact, right?

Wear your eye protection! :cool:

[Richard Dooling]

Good point Jacob. I did not heat the arbor too long or get it real hot so I think it's OK. I just used a plumbers torch and really just warmed it up. It made no sound when I hit it with the water.

[Dean Karavite]

I have the same saw and my advice is buy the cabinet saw! :D

[Cliff Rohrabacher]

I'm going to heat the nut/arbor with a torch - just enough to get it good and hot - then flood it with ice water.

I would not take a torch to the arbor.

The thing is attached to bearings that have poly seals that will melt and cause the bearings to bleed the lube out and seize. The six or fifteen different types of damage you could do not counting heat distorting the arbor and of a certainty drawing all the temper out of all the hardened parts is a bit one the hefty side.

Your friend has the idea correct but only half way right. Thermal shock is not why one might bring a torch to the party,. One will be hoping to heat the stuck nut so that it grows a little in size and then is easily removed.


As an aside, if the thing is a direct drive, you run a fair chance of killing the motor.

[Joel Blauvelt]

Grab the blade (not the teeth) with a good pair of vise grips. Rotate the blade/vice grips so that they rest against the table. This should keep the arbor from turning as you take a big closed-ended wrench and give it a good pull.