Adapting to an Oversize Table Saw Arbor

Ideas for modifying blades to fit an oversize arbor, or vice versa. August 21, 2006

I picked up a Rockwell/Delta table saw for a song. 12/14" 5hp, the works... Guy just didn't know what he had.

My question is the saw blade. The arbor is 1 1/8". I have had some trouble finding saw blades with an arbor hole that size. For the moment I had a blade bored to the size, but I get a lot of runout. It really needs to be factory machined. Forrest can do custom boring, but ouch on the price. Anyone run into this? Where do you get yours?

Forum Responses
(Furniture Making Forum)
From contributor C:
I wonder if you could take the motor out (assuming it's direct drive) and clamp it to the bed of a metal lathe, and let nature take its course. I would think if you take it to a local metal shop, they could manage to turn the arbor down and replicate the threads. I would not leave it as an odd size unless you can find a reliable supplier of blades.

From the original questioner:
Actually, it is belt driven, and I changed it from 3 phase to single (small shop). Thought about machining the arbor, tried to get it out, no luck without messing up the castings. So I'm looking for a saw blade and dado set. This is a Delta; can't believe no one has one out there. Nice saw. I'll go with Forrest if I have to.

From contributor K:
I have the same saw (Rockwell 12/14) and anyone that has spent any time on this saw knows what a great machine it is. I've had mine for 10 years and could never go back to anything as small as a 10" Unisaw. (It's a joke, guys).

Now about your arbor. The earlier 12/14 had interchangeable arbors to accommodate the collection of blades a shop may have. The flange on the arbor should have 2 holes that are to be held with the original arbor nut wrench that came with the saw (one end of the wrench was for the arbor nut; the other, a spanner wrench). On the end of the arbor should be flats machined to accommodate an open end wrench to unscrew the arbor from the flange. Remember, this will be a left hand thread (unscrews the same direction the arbor nut does). The original manual shows several arbors - 1", 1 1/8", 1 1/4", in several lengths. Unfortunately they were not available when I bought my saw, but I had the ability to machine my own. Since then, Grizzly Imports has copied the 12/14 and offers a saw with interchangeable arbors and they appear to be the same ones as the 12/14. In fact they have come up on E-bay several times. Someone on E-bay had listed a 5/8" arbor (which the Rockwell 12/14 never had available) for the 12/14. Obviously these are made overseas. Sometime in the '70s they changed the 12/14 over to a straight 1" long arbor. The spanner end on the arbor wrench is also needed to unscrew the retaining ring to remove the inboard bearing.

From contributor R:
Before doing anything drastic, contact RKO Saw and see what they may have for your needs. They are a custom saw shop and do an outstanding job. They may be able to deliver what you need without it costing too much more than an off-the-shelf price. I have found their prices to be very competitive.

From the original questioner:
Great! Where I could get one of those wrenches? It is a great saw. Should I have the arbor machined, get another, or use the 30mm as someone suggested (didn't think about metric)?

From contributor K:
You should have a parts list. Get it from, go to Delta, table saws, 34-350. You'll then see nothing is affordable. They want $106 for the wrench, which is stamped steel, and $300 for the arbor extensions. I'll measure the spanner for you (about $20 from a machinery supplier), and I'll check on the arbor extensions.

From contributor C:
I would really go for the 30mm bore blades. Any professional sharpening service should be able to get you these in a full range of options. They also have larger bores, but these are for 16" and larger industrial blades. The less time spent monkeying around with the new machine, the better.

From contributor L:
Have blades bored out to fit the arbor. You can buy bushings to interchange the blades on other machines. We do this all the time with our tools. Cheapest and simplest way to go. Your saw sharpening shop should be able to help. If not, you need to find another sharpener.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor S:
I am a shop teacher in a Long Island school district, and we have a 1959 Delta Milwaukee Crescent 12"/14" table saw with a Rockwell serial number. I too had the problem of having to bore new blades from a standard 1" bore to a 1 1/8" bore. The cost of boring often exceeded the cost of the blade. I contacted Delta, and they had me read the casting numbers from the trunion and table extensions to them. They had a 1" arbor that fit my saw. I bought it and it works perfectly, and now I can use standard 1" bored blades. I can change the arbor at will to use my old 1 1/8" bored blades, but I found it's easier to buy bushings and snap them in rather than to change the arbor.

Comment from contributor D:
You'll need a good drill press and a 5/8 diameter sleeve around the pilot bit to chase your existing 5/8" arbor and keep the cutter centered. You have to wax these up good before drilling.

I have an old 7" Black and Decker hand circular saw that has a 1-1/8" arbor and it's a beauty. I found that turning it down to 5/8" is not an option because the arbor slides onto a splined shaft that's almost 9/16" by itself. I researched having blades re-bored at over $17/blade and decided against that too. Now I've decided to have the arbor altered to accept blades with the diamond shaped knockout removed. It seems to be the most economical approach.