Shopsmith Forums

wa2crk wrote:Tom
Very innovative approach!!! I am not one of those who favors lathe mounted sharpening systems. The tools will need sharpening during the turning and I dislike dismounting the turning to touch up the chisels. But those folks with stand alone lathes will like the idea I am sure.
Bill V

That is why a 2nd and/or 3rd SS is mandatory, and at least one of them an ER, and if it has the coveted Speed Changer, down to 425rpm

While generally I am all for using the SS for creative things, this seems like it might not be the best use. Maybe on the aux side of the headstock.

With slow speed grinders so inexpensive, that seems like a better choice. Clamping the board that the bench grinder is mounted on to a extension table gives you many of the same benefits, without any changeover issues.

Hi Tom;

I liked this idea, so I ordered up a CBN wheel from Wood River and a dado arbor from SS. They got here a few days ago, and I am impressed with the quality of the wheel. It looks great and feels really solid. Problem, though, is that when I mount the wheel on the arbor, I can't get the nut to fully seat. That is, the end of the arbor is a full 1/8 of an inch below the surface of the nut. Looking at the photo in the original post, I think I can see the arbor extending out a little bit beyond the nut, as it should. So I am wondering; How did you get the nut to fully seat? Were you able to find a 3/4 inch wide wheel with a 5/8 arbor hole? Is the wheel in the photo the 1" by 8"? That is the only size I could find with a 5/8 arbor hole. I would appreciate any light you could shed on how you set up the wheel. And, also, I would be interested in hearing your experience with this rig now that you have had it for a while.

Thanks,

Are you using a saw blade arbor or a dado arbor? The original post states he is using a dado arbor for the CBN wheel.

The dado arbor.

On the internet I found a rule of thumb called something like the "3 thread rule" which, if I understand it, means that the bolt to nut connection is at full strength as long as at least three full threads are engaged. I can get just over 7 full rotations of the nut on the arbor before everything is snug, which does not quite bring the end of the threaded portion of the arbor flush with the top of the nut. The cbn wheel is surprisingly heavy and I don't want to take chances with a less than full strength connection. My thoughts now are either to find a slightly smaller nut of the proper thread or just give up and get a slow speed grinder with a 5/8 spindle. Hate to do that though, since I really like the idea that the shopsmith will let me sharpen at speeds lower than any bench grinder.

edflorence wrote: Sun Oct 20, 2024 7:00 pm The dado arbor.

On the internet I found a rule of thumb called something like the "3 thread rule" which, if I understand it, means that the bolt to nut connection is at full strength as long as at least three full threads are engaged.

Isn't the 3 thread rule that 3 full threads should extend out of the nut?
What is the thickness of your wheel at the hub? The shaper arbor has enough length for several spacer disks plus the nut.

The current Molder/Dado Arbor P/N 505506 has the longest threaded end of all 4 versions of P/N 505506 the Molder/Dado Arbor previously the 5/8" Universal Arbor. If you are using it with the 2 machined washers as would normally be done, I would suggest trying a pair of regular 5/8" washers which would be thinner. That will give you more of the threaded end for the nut.

For reference the 4 versions of P/N 505506 the 5/8" Universal and Molder Dado Arbor are shown below. They are from left to right the earliest version to the current version unless Shopsmith made a recent change and a fifth version. You can see in the 4th version the threads extend past the nut.

_

Ed - Your interpretation of the "3 thread" rule sounds better. I have always heard that for a solid connection there should be a minimum of one full nut of engagement. Three threads past that would be very secure. The hub of the Wood River wheel is 1".

Russ - I am using the most current version of the dado arbor. This is the one I just ordered a few weeks ago. When it showed up, it was nicely bubble wrapped, but came with no supporting information. Luckily, I still have the sheet of instructions that came with the dado arbor I ordered years ago, so this afternoon I pulled it out and lo and behold, there is the answer to my question. I am attaching an image of both sides of that old instruction sheet, which clearly states under the list of Warnings: "Do not mount accessories thicker than 13/16 on the arbor." Case closed, I guess.

It doesn't look like the OP has posted in about eight years, so I'm not optimistic that he will weigh in. But best I can tell he has a 1" CBN wheel on a 5/8" SS Dado arbor. Based on the part we can see in his pictures, I'd guess that he did not use an 'inside' washer. While that use is not correct according to the instructions, I don't really see an issue.

Many of the CBN wheels I see on Amazon have aluminum centers and are not full thickness over the entire wheel. While I'm not suggesting that is better than the steel full thickness version, one could probably reduce the thickness at the hub if necessary without much difficulty.

- David

edflorence wrote: Mon Oct 21, 2024 4:26 pm Ed - Your interpretation of the "3 thread" rule sounds better. I have always heard that for a solid connection there should be a minimum of one full nut of engagement. Three threads past that would be very secure. The hub of the Wood River wheel is 1".

Russ - I am using the most current version of the dado arbor. This is the one I just ordered a few weeks ago. When it showed up, it was nicely bubble wrapped, but came with no supporting information. Luckily, I still have the sheet of instructions that came with the dado arbor I ordered years ago, so this afternoon I pulled it out and lo and behold, there is the answer to my question. I am attaching an image of both sides of that old instruction sheet, which clearly states under the list of Warnings: "Do not mount accessories thicker than 13/16 on the arbor." Case closed, I guess.

I looked at my 5/8" dado/shaper arbor and the set of spacers look like they total about 13/16" with 3 or 4 threads showing. However, if you're just using the wheel for sharpening you should be applying much pressure on the hub even with an 8" disk. I don't think you need a washer on the arbor side of the screw and maybe nothing but the tabbed locking washer on the outside or a thin steel washer under that. It's not a shaper bit or a saw blade being mounted. If you've got a couple of threads showing on the screw. I think you'll be fine for this application.

I have a 1"x6" CBN wheel. The hub is very thin, no more than 1/4" I think. I use a 1/2" universal arbor on that.