TS Arbor Nut

Alex Reid

Member
Messages
739
Location
Zushi, Japan
My table saw arbor nut just plain wore out on me. I noticed the other day when I gave it the last torque it skipped a little. After doing that a couple of times it gave up the ghost and couldn't hang on any more. So while my TS is out of order I have a nut on order. But it kind of piqued my curiosity. Obviously the arbor is hardened more than the nut allowing the nut to wear out and not the arbor itself. Does anyone know the ratio of hardness between the nut and arbor? Any guesses?
 
Something wrong here I have both a 1940 Unisaw purchased well used by me & a 1957 Craftsman contractors saw which was purchased new by my Dad & use in a commercial cabinet shop. Both just fine after all these years.

You usually only need to just snug the arbor nut reasonably tight & not crank it down forcefully, it will tighten down further by the very virtue of being against the blade.

I'm sure you already know all this.

What brand of saw & how old is it?
 
Totally agree Bart, you only need to snug it down and not crank on it. However mine has worn out. I have a Delta 10" Contractor's and have used it for about 10 years.
 
No help here on the hardness rating...but...

Maybe check the threads on the arbor also... they may be worn down...they should be flat on the top of the thread, over time they can become rounded off, if so an arbor change is in order...
just thinking out-loud :thumb:

& agreed..just snug it up {or down ;)}. The direction of the blade rotation will keep it from loosening up.
 
So how the heck did ya manage that one Alex? I agree there is something else at work here than just the nut. I have used saws on the job site that are well over 10 yrs old and have never had the nut changed. And trust me those saws have been really abused by a bunch of neanderthals. I mean lots of other things get broken on the saws but that is not on the list. Maybe ya need to cut back a bit on the wheaties. :D
 
Alex how about a picture of the nut's threads and the arbor threads?

I too am a bit surprised that this would be a problem. Is there a washer the goes between the blade and the nut? Could you add some kind of spacer to the arbor between the washer and the nut? This way the threads on the nut would be engaging on a different spot on the arbor. If it tightens down OK, then I guess it is the nut, but if it is still loose then the arbor may be bad some how....... dunno how, but....?

Can you check with delta and see if there is a recall on that saw?

I seem to remember an orange maker of tools that had a similar problem a while back, turned out to be a bad batch of arbors, IIRC and I may not :p

I wonder as well if other saw's arbors and nuts are the same thread etc?

Curiouser and curiouser..... :D
 
The new arbor nut arrived the other day. I put it on and everything is back in order. Today I took a picture of the two side-by-side. I also measured the inside diameter and found the old worn out one is 15.8mm, while the new one is 14.98mm. Old is on the left and new on the right.

arbornut.jpg
 
Either that is a HUGE vernier caliper, or those are small arbor nuts :eek:

The one on my saw now is about 4 times as thick and a much larger size.

I'd have bought TWO and wired one to the saw somewhere so you don't have to worry about getting another one down the road....... but wait, I thought you were going to upgrade that saw...?

Good to see your got it fixed, that difference in the ID between the new and the old nut is substantial.
 
Either that is a HUGE vernier caliper, or those are small arbor nuts :eek:

The one on my saw now is about 4 times as thick and a much larger size.

I'd have bought TWO and wired one to the saw somewhere so you don't have to worry about getting another one down the road...

The arbor nut on my Shop Fox saw is also much thicker than those, and like Stu, I have a spare "just in case." You never know when you're gonna drop one, and have it fall into the sawdust pile, or into the DC ducting... A big magnet on a stick can be your friend when that happens. DAMHIKT...:D
 
Either that is a HUGE vernier caliper, or those are small arbor nuts :eek:

The one on my saw now is about 4 times as thick and a much larger size.

I'd have bought TWO and wired one to the saw somewhere so you don't have to worry about getting another one down the road....... but wait, I thought you were going to upgrade that saw...?

Good to see your got it fixed, that difference in the ID between the new and the old nut is substantial.

Those calipers are 150mm size. Got em in Akiba just outside the station where all those little stalls are in that 4 story building.

I almost updated the saw but still need 200v in my workshop. I have been thinking again recently about doing the upgrade soon and was thinking of getting some advice from you...
 
Most North American marketed saws have a 5/8" (15.8mm) arbor with an Acme thread. Is that what yours is, too? If so, Enco, Grainger, McMaster-Carr, and others sell the thicker nuts. I'm sure there mus be a Japanese supplier for them, too.
 
When I was in high school my dad told me to just snub the TS blade nut. I was not supposed to put any "extra pressure" on the wrench. I have never had a nut go bad nor have I had one come loose.

I have one of those fairly soft, orange, plastic blade holder gizmos. I just squeeze it on both sides of the blade using thumb and fingers. When the blade starts to slip, I quit tightening.

I realize that is a very precise, scientific measurement---like a pinch of salt---so that is what I do.

Enjoy,

Jim
 
Most likely the nut has been overtightened many times. When you do that it can upset the threads and if there is sawdust on the threads that will further aggravate the situation.
The arbor should be of tool steel maybe hardened and ground. With the threaded area possibly annealed and then the threads machined. If the arbor is made from 4140 steel then those threads will be harder and of higher quality.
The nut could be relatively soft if not dead soft. The material has more to do with it's hardness/ durability in this case. However nuts are commonly sold in 3 basic grades. Grade 2 has no markings and can be made out of cold rolled steel and just about anything else these days. I don't trust that what you buy from China is controlled or to any standard. Grade 5 is hardened and has 3 radial lines whereas grade 8 is harder and has 6 radial lines on the side of the nut.

My saw has a flange nut and flange nuts are generally hardened. I would guess grade 5 but I haven't looked.
 
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