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View Full Version : General Metalworking Fabricating an adaptor sleeve for my table saw?



Dennis Aspö
08-01-2014, 6:52 AM
I asked this question elsewhere and the consensus was it should be doable, though there was some argument about the details. But I figure the more people who weighs in on it, the better.

I got a 20mm arbor on my table saw, the standard in Europe where I am is 30mm and I wouldn't mind having to not bother with adapter rings, though my main idea is also make a longer arbor so I could fit a dado stack. I heard somewhere about someone making an adapter sleeve for his table saw and that's where the idea took root.

What I was thinking was an internally threaded part that simply screws over the arbor I currently got. Arbor pictured below:

https://farm4.staticflickr.com/3902/14411617358_52b87a508d_b.jpg

Someone suggested the adapter being held in place with a grub screw and another said it was not required because the thread pitch means it's self tightening and a grub screw would prevent it locking down tight. Any opinions on this here, sound doable or just plain crazy? I have no idea what it'd cost to manufacture such a part either, if it gets too expensive I think I'm better off getting a router (something I plan on eventually anyway). I might also build Matthias Wandels screw advance box joint jig to get around this lack of dado capacity for now.

Rich Enders
08-01-2014, 9:47 AM
Dennis,

About 20 years ago I had that type of adapter built for a Euroshop (SCMI) combination machine. These machines were being imported into the US from Italy, and came with a 5/8 inch diameter arbor which protruded just enough to hold a blade, the arbor flange, and the nut. I had the adapter built 1 inch in outside diameter, and bored and threaded inside to fit over the existing arbor. The adaptor was then threaded on the outside to accept a 1 inch bore dado set, a 1 inch arbor flange, and a 1 inch arbor nut. I had it made by a local machine shop, and I think it cost about US$ 100.

Keep in mind that the motor on your saw is scaled for the load created by a single saw blade. Adding a dado set increases the start up torque requirements, and also the load while you are cutting dados.

The adapter worked well for me, but I am not a commercial shop. I sold that machine 12 years ago to a manufacturing company that uses it in their model shop. Even today the combination machine works well for them, but they are doing light to medium duty work only.

Dennis Aspö
08-01-2014, 2:44 PM
OK I think I should be fine on the motor front though, it is a 3.3HP 3-phase motor so I think it is powerful enough.

Dennis Ford
08-01-2014, 7:37 PM
A decent machinist should be able to make what you describe; I would recommend that you talk to a few and get estimated prices before having it done.

Rich Enders
08-01-2014, 8:05 PM
Dennis,

The Euroshop combination machine drove the table saw section with a 4.8 hp single phase motor. I know nothing about motors, but prior threads on the same subject mentioned possible issues with the start up amperage, the operating temperature of the motor under load, and the capability of the bearings. I had no troubles, and the new owner is still making dadoes, so I guess this motor had what it takes, or the owner(s) treated it right.

Dennis Aspö
08-02-2014, 3:11 AM
IIRC I've heard anything above 2.5hp 1-phase should be enough for dado usage. 3-phase motors are stronger than 1-phase equivalents, it has way more torque and is more energy efficient. The machine was a german industrial machine for 40 years so it's made for heavy use, still got another 140-200 years of use in it with maintenance done properly.

Rich Enders
08-02-2014, 7:26 PM
Dennis,

So it sounds like having an adapter built is a good option. The photo looks like you have left hand threads so it will be self tightening. My adapter was no problem to remove either. Goof luck.

Dennis Aspö
08-05-2014, 3:32 AM
It does sound doable, but it'll probably have to go on hold for now, but it's good to know it can be done!

I think it's more economic for me to try and build matthias wandels box joint jig for now so I can make box joints with a regular blade. I don't own a router and I don't have the money to buy one either at the moment (also no money to pay for an adapter or dado set).