Shopsmith Forums

The blades are sharp,

the blades are combination blades (not using a cross cut to do ripping)

there is no binding between the work piece and the fence,

the feed rate was proper,

the wood was not wet (green),

the power is dedicated (not shared with other load)

and yet 3/4" plywood bogs the motor.

Does that summarize where this is at' except that a thin kerf blade does great on dimensioned lumber

I may be entirely wrong here but I always have an opinion. The blade in question appears to be an ATBR blade. Alternate Top Bevel with Raker. I have always been of the opinion that the raker tooth always trailed the ATB teeth in the set. The ATB teeth remove the bulk of the waste and leave a clean shoulder and the raker tooth cleans out the remainder of the waste. ATB teeth leave a kerf that has a "V" at the bottom of the kerf and the "V" is removed by the raker.
In picture #3 of your post it looks as though the raker tooth is leading the group of 5. If this is the case then the raker tooth is cutting the entire kerf and the ATB teeth have nothing to do. My opinion is that you may becutting with only 8 teeth and not the entire 40.
Just an opinion.
Bill V

The raker tooth is 'behind' the deep gullet. Sequence? if every fifth tooth is a raker, how can one say it 'leads' the cut?

JPG wrote:The raker tooth is 'behind' the deep gullet. Sequence? if every fifth tooth is a raker, how can one say it 'leads' the cut?

I guess that depends on where one believes the cut begins.

The deep gullet works to clear the kerf of sawdust. Once clear, a new cut begins. Where does this process begin and end?

None the less, I do not believe this is the explanation for why the saw blogs down!

The OP says this is an older-style Shopsmith full-kerf, carbide combination blade.

I had and used one of these exact same blades for several years and cross-cut and ripped 3/4 ply with it many, many times, without incident, until it finally threw a tooth and I retired it.

Accordingly, I consider it a proven fact that a properly set up Shopsmith on a proper electrical circuit with an appropriate extension cord will cut 3/4" plywood with an older-style Shopsmith full-kerf carbide combo blade without bogging down (assuming proper feed technique with large sheets).

For the same reasons, based on personal experience, I also consider it rubbish to speculate that the older-style Shopsmith full-kerf carbide combo blade has a design flaw in terms of the arrangement of the teeth.

The obvious conclusion is there is something wrong with this particular older-style Shopsmith full-kerf carbide combo blade that is not obvious to the naked eye or in a photograph.

This blade came to the OP used. While it is reportedly clean and sharp today, we and he know nothing about what may have happened to it in the past that make it a substandard performer today.

It may have been sharpened in the past improperly with the wrong angle/grind by an incompetent sharpener or by the the previous owner. It could have been overheated, warped and straightened poorly.

I suggest that OP test it one more time on some other stock. If similar performance issues arise while ripping, chuck the blade and get a new blade, (full kerf of thin kerf). Or send it to Forrest. They will figure out what it needs.

Yes, these are true, subject to my own observation/technique

Great feedback from all of you, as usual.
I will try with other stocks, and report back to you, if there's any observations worthy additional discussion.

dusty wrote:The blades are sharp,

the blades are combination blades (not using a cross cut to do ripping)

there is no binding between the work piece and the fence,

the feed rate was proper,

the wood was not wet (green),

the power is dedicated (not shared with other load)

and yet 3/4" plywood bogs the motor.

Does that summarize where this is at' except that a thin kerf blade does great on dimensioned lumber

Are you experiencing burn marks ?
What happens if you try on a small piece of 3/4 ?
Are you running the motor too slow ?