Why Shopsmith uses a 1 1/4” bore in their blades

[thedovetailjoint]

I posted a video yesterday where I discussed a couple of the theories of why Shopsmith uses a 1 1/4” (1.25”) bore in their blade. Over the years I’ve heard several explanations, and in the video I went to the source to get the “final” answer. Check it out here: https://youtu.be/NQlZUk-8eHQ

[chapmanruss]

Scott,

Nice information about the origins of the 1-1/4" Arbor.

For those of you who would like a better look, the picture below shows one of those original 1-1/4" Arbors that came out in 1954 with the introduction of the Mark 5. This Arbor has changed a little bit over the years. As was the case with those original Arbors and accessories they did not have the black protective coating.

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22 032.jpg (89.02 KiB) Viewed 2088 times

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The one above was part number 22 032 which later became part number 505511 which is still the part number for the 1-1/4" Arbor for the MARK V Model 500 today.

An interesting side note to this subject is the Mark 5 was introduced with a 9" Saw Blade as opposed to the 10" Saw Blade we now commonly see. That Saw Blade size change occurred in the 1960's.

[DLB]

My guess at the reason wasn't covered. Sales and Marketing. I would guess that Shopsmith sells far more blades and arbors than they would if they switched to the 5/8" 'standard.' Just looking in my own shop I have considerably more SS blades and arbors than I'd have if the machine, when new, came with a 5/8" arbor. I very much like the current crop of 1-1/4" arbor blades offered by Shopsmith, one of which comes with a new machine. (I agree, probably Amana.) But none of which came with my machine. I likely never would have tried one if I didn't have 1-1/4" arbors, now I have the set. I also have SS brand 5/8" arbors I use regularly, SS no longer sells a 1-1/4" arbor plywood blade. (Though they sell a 5/8" arbor plywood blade.)

I tend to discount the historical aspects of the 1-1/4" arbor. The machine (and/or Saw Work Package) still comes with a 1-1/4" blade and arbor, despite the availability of a 5/8" for decades. I suspect this leads to more follow on sales of replacement blades, as well as accessory blades and arbors of both sizes.

- David

[RFGuy]

My guess at the reason wasn't covered. Sales and Marketing.

David,

I am with you on this one...I don't consider a patent as a valid argument for why Shopsmith chose this sawblade bore size and continues to use it to this day. WITHOUT some kind of internal Shopsmith document that explains the choice, I would say this is still an unknown and there are multiple theories for why Shopsmith went this direction. At this moment, I would tend to agree with you that it was a sales and marketing decision to try to make it standout from the competition and/or lock customers into buying blades directly from Shopsmith. Bottomline is we will never know the real answer with 100% certainty, I am sure of that.

[JPG]

I am inclined to go along with Scott's explanation.

Too many details simply align.

[jsburger]

I am inclined to go along with Scott's explanation.

Too many details simply align.

I totally agree. SS was an innovator back in the day. They did things for a reason and back then it was not for sales of proprietary items. Scott's explanation is right on point. We have all been lead to believe for ever to think that the SS 1 1/4" arbor was a ploy to sell their saw blades. SS was in the business of selling wood working machines not saw blades. They wanted the best and SAFEST machine they could produce. Scott's patent research shows that.

[RFGuy]

Still skeptical...

[JPG]

Still skeptical...

Why?

[RFGuy]

Still skeptical...

Why?

The existence of a patent does NOT prove that this was Shopsmith's intent for going with that bore size. Yes, I understand that that particular arbor requires a larger bore size, but they could have sold different arbors, some smaller, then as well if they chose. IF you go back to Doug Reid's YT video where he explained this he gave a different reason for that bore size from Shopsmith. I believe Doug was a Shopsmith demonstrator and worked in the Academy for many years. He and others have given different reasons for the "why" that Shopsmith chose this bore size. Which one to believe??? All of them had direct contact with the factory and yet there is disagreement amongst them. Lastly, there could be more than one reason for the why that Shopsmith chose this particular bore size and opportunity for a patent may be but one.

[JPG]

"Opportunity for a patent places the cart before the horse. Rather the patent leads to the necessity of the larger hole. Consider that the 1 1/4" hole was not created by SS but was a common size for larger commercial blades.

IIRC Doug mentioned the elimination for blade stabilizers - an added reason to have the larger hole.

I think Scott has done his homework.