SS jointer with carbide bits? Ask Mike...

[benush26]

This morning for some odd reason I wondered if a carbide bit holder/carrier (aka modifying conventional blades) could be built which would allow the outfeed table to stay fixed, still using the same height adjustment as the steel blades.

These drawings are NOT to scale to or anything like that! The carrier is not the correct nor appropriate dimensions nor are the bits to scale. I don't even show the bevel on the bits (which I think would have to be mounted backwards from a conventional mounting system since the recess for the screw head is usually on the thinner side of the taper- for the cutting action to work ) Just a quick sketchup drawing to provide a concept I don't even know if this is feasible, just curious.

From the front... The three holders/carriers would NOT have Identical horizontal mounting positions/threaded holes for the bits. By moving the entire set of mounting holes left (or right) each holder would provide a unique bit position. That might help eliminate the slight ridges found in planers and thus the jointer which are NOT using the spiral attachment system. First question for the engineers out there. Could the bits be installed side by side with no gap (as I have shown them) or would heat cause an expansion and possibly chip/crack the bits?

holder front1.PNG (111.84 KiB) Viewed 1637 times

By machining a ledge for a beveled edge to abut, I was thinking that this would keep the bits from rotating when in use. The view does not show it, but the faces of the bits protrude past the vertical surface of the bit holder. How far would be safe and still provide adequate support for the bit yet not cause interference? 1/64"? 1/32? more?

holder side.PNG (129.52 KiB) Viewed 1637 times

Granted this would not provide a spiral cutting action, but would provide the durability and quick change of a carbide bit. I'm not certain how much backing the bits would need to provide support. Would 1/32" exposed carbide be too much? 1/64"?

Also,since the bottom to top thickness difference on the conventional steel blades as a safety measure, given the bottom to top taper, would it be necessary to then thicken the upper half to provide even more support for the carbide bits, (which would totaly eliminate teh plausible and possilbe use of OEM ShopSmith blades to be modified as a carrier), or could a conventional blade be milled at the top enough to provide that ledge for the bits and still keep enough structural integrity?

Before anyone starts talking about perceived safety issues, I was wondering if anyone on the forum with "qualified" metallurgical knowledge could provide some insight.

If it MAY be feasible then I would take a spare set of unsharpened blades to a machinist to have the ledge cut and precise holes drilled and tapped.

Feasible? Probably not. But maybe something for one of the more competent design/ builders mechanical mavens on this site to take and see what IS feasible.

I've cut pasted reviewed revised and modified the text so any and all typos, reiterated reiterations and other mental screw ups are going to stay and I'm going to post this!!!! Hopefully those of you kind to the addle brained will ignore the mistakes!!

Be well,
Ben