Sommerfeld Replacement Bearing Arrived Today

[Bob Wingard]

Got a package in the mail today and it was the replacement bearing for the Sommerfeld Cabinetmaker's Tongue & Groove joining system. My sincere thanx to Marc, Pat, Donna, and/or anyone else at their end who finally made this happen.

I knew from past experience that (for my set) the bearing O.D. should be 1.185" in order to make a true 1/4" deep tongue. As soon as I opened the package, I went right to the mic and found the O.D. to be 1.196". This may be an overall compromise as some sets might have slightly different dimensions. I did a simple setup using available shop tools and modified the replacement part to be a more exact cure .. again .. FOR MY SET .. .. yours might be different. I would encourage everyone who receives this replacement part to try it AS DELIVERED to determine if you need to make any changes/adjustments. I suspect many will work just fine as they are. Even if the set is off by 0.011" it will be far less noticeable than the current 0.035". If, after trying the part anyone wants to learn how I further customized mine, I will be glad to post the procedure here. It is not at all difficult, but it is a one-way trip so if you damage your part, well .. it's YOUR damaged part. I will openly share this information and you may take it for what it's worth, but I will assume no responsibility for your individual results.

Again .. .. .. thanx to the Sommerfeld group for finally making this a reality. Since I've been the first to hammer them for their shortcomings in the past, I want to also be the first here to congratulate them for stepping up and doing the right thing in the end.

[Steve Clardy]

Sounds good

[Al Navas]

I am glad that you are good to go, Bob. Thanks for sharing!


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[Barry Londrigan]

I too received my bearing in the mail. Thanks goes out for the replacement bearing. Bob, I am right with you, pretty much to the letter. I measured mine and the new bearing is 1.1955.

Now, on my set, the measurements for the groove cutter are 1.7545 (cutter) minus 1.2490 (bearing) = difference .5055 and divided by 2 = .25275 for a groove.

The tongue... 1.6910 (cutter) minus 1.2490 (bearing) = .442 divided by 2 = .221 for a tongue.

If I simply subtract the difference of the groove cutter and bearing from above (.5055) from my tongue cutter dimension (1.6910) I get 1.1855 or simply my new bearing size that I would need to make an exact fit with my tongue and groove cutter.

My new bearing size is 1.1955. If I take the difference I have .01 or 1/100th of an inch. But this is for two cuts (which would equate to the two cuts required to install a back panel of some sort - nail rail or what have you). So if my math is correct, it would take three cabinets together on a wall to make the back of the cabinets grow a 32nd of an inch (.03125) or .01+.01+.01 = .03

SO....IS my math right?

Am I rententive? You betcha! :)

Can I live with that? Doubt it...so Bob...how did you modify yours??

[Bob Wingard]

Barry .. .. in a way I'm glad to see that your dimensions are almost exactly what mine are .. .. .. makes me think the error was at least consistent.

Now .. .. . on to the customization of the new bearing .. .. .. as I stated earlier, I will share this information, but you are on your own as to it's use !! !! !!

If I were still working in a shop that had a toolpost grinder on a lathe, it would be much simpler to guarantee perfect dimensions and final finish. For this particular application, patience will yield the proper dimension, and the finish will be quite acceptable.

I stripped everything off of the tongue-cutting arbor, keeping all the parts in order. Since that arbor is threaded only out on the end, I built-up the void with about a 10 washers, placing the bearing in the middle. The washers will squeeze the outer race of the bearing, locking it to the arbor. Now for what is probably the most critical part .. .. .. I chucked-up the arbor in my drill press .. .. be sure to check concentricity of this assembly at this point if you choose to attampt this modification. If your assembly has more than about 0.0005" runout, I would probably not attempt this, and I would look for someone with a lathe & collets to perform the next step. Since the bearing race is very hard and tough, filing or stoning away 0.011" was out of the question, so here goes the method I tried. With the assembly chucked-up in the drill press, I clamped a machinest square to the table just to use as a visual reference of perpendicularity to the table surface. I mounted a brand-new rock in my Milwaukee 4 1/2" side grinder .. .. held it it close proximity of the spindle .. .. lined the face of the stone up with the square .. .. turned them both on .. .. and LIGHTLY touched the spinning rock to the also spinning bearing race. BE SURE TO USE EYE PROTECTION if you attempt this procedure. I used safety glasses AND a full-face shield. I didn't EXPECT either piece to come apart, but there you are with your nose right up close to two hard objects spinning in opposite directions .. .. .. By closely watching the scratch marks on the O.D. of the bearing race, you can tell if your guess at perpindicular was correct or not. Proceed with several light touches in the same manner. Stop and check frequently, and you'll get an idea how long it takes to remove 0.0005". Continue grinding and checking until you are about 0.0003" oversize, and use a diamond stone to polish up the remaining scratches and you should be right at 1.185"+. It worked just fine for me .. .. .. tried it out and got near-perfect results (I have to call it NEAR-perfect 'cause there's no such thing as PERFECT). Don't forget to recheck the tongue WIDTH, just in case the replacement part is thicker/thinner so you can arrange shims as needed.

I got lucky .. .. .. the whole thing took all of about 20 minutes to perform and worked like a charm. If you don't have the equipment/patience/skills to do this, I would definitely recommend against trying it. If you need to take off that last couple of thousandths and lack any of the above .. .. .. be patient and seek out someone who does .. .. .. you might even find a hobbiest with a metal-lathe and a tool post grinder.


Good Luck .. .. ..