Shopsmith Forums

I have a Mark V with the planer attachment. Recently I ground and sharpened the blades to like-new condition and they have worked great.

I'm making a new tiller for my boat where I sandwiched two layers of maple between two layers of red heart and I epoxy'ed all that together with a sheet of carbon fiber between each layer.

The plan was to plane/joint it square then shape where needed using a grinder and a lot of sanding. The problem I've run into is that when I put the piece into my planer, after just a couple passes, the pieces weren't coming out smooth anymore. There were long grooves being left all over. When I inspected the blades I saw they had been really chewed up, with deep cuts in the blade up to 1/16" deep, I think from the CF sheets slicing into the edges of my. planer blades.

Here is my question, I've got the stock SS blades, is it worth it to upgrade to the carbide alternatives I've seen online? Would those have met the same fate? What about the shelix cutterhead? I'm not seriously considering the shelix at $644 (unless someone knows where I can get one for cheaper), just wondering if planing (or cutting) wood with CF in it is just never a good idea. I think my actual options are to regrind the blades I've got, buy new stock ones, or upgrade to the carbide ones I'm seeing on mywoodcutters (https://mywoodcutters.com/Carbide_Blade ... aner_M5082).

Thanks!

I think both the epoxy and the carbon fiber would be exceedingly tough on steel planer blades. I expect carbide might stand up better but I a not certain and if it were me I would talk to the manufacturer before making the investment.

Considering that most finished tillers aren't perfectly straight and square anyway, why not just take the blank over to the Shopsmith belt sander to clean it up before you go to town on it with the grinder? Actually you probably could do the whole job on the belt sander. That's what I have used to shape the sculpted yokes for my canoes.

I would suggest that it is now time to do some real wood working. Turn off the power sander and the planer and dig out the hand tools and sanding blocks.

I vote for the belt sander option - 6” sanding belts are cheap at Harbor Freight. Commercial re-sharpening of carbide tipped planer knives is pricey and would almost certainly be required after only a few passes. I found out the hard way thinking I could avoid paint stripper & scraping by using my planer to skim off a layer of paint on some reclaimed lumber. Not a good idea.

Any hand held sander(powered) would be a better approach.

Carbon-fiber composites are often machined on CNC routers. The router bits designed for that purpose are typically PCD (poly-crystaline diamond) coated carbide. With a CNC, you could machine the tiller to final shape. For merely flattening it, a simple router sled and one of those PCD-coated bits should do the trick.

I’m curious about the location and purpose of the CF sheets in your design. At first, I assumed that you were laying it up like plywood, with the CF sheet sandwiched between wood layers, where it could help prevent warping of the panel. But in that case, you’d have all wood on the outside faces, and your planer plades would never touch the CF.

BuckeyeDennis wrote: ↑Mon May 27, 2024 9:09 am I’m curious about the location and purpose of the CF sheets in your design. At first, I assumed that you were laying it up like plywood, with the CF sheet sandwiched between wood layers, where it could help prevent warping of the panel. But in that case, you’d have all wood on the outside faces, and your planer plades would never touch the CF.

Same question from me. How do the blades come in contact with the laminate? Are you cutting the edge on a joiner when this happens?

Anyway, not sure why you are doing it this way. Sanders seem to be the proper tool for the job.

About why the blades are coming into contact with the CF at all, these layers are laid up vertically so the red heart layers are on the sides, about 1/2" thick each, with two maple layers in between, also about 1/2" thick each, for a total of 3 CF layers. The entire blank is 2" wide x 1.25" tall x 38" long (not a large boat)

About why I'm planing at all vs belt sanding or using hand tools, honestly I don't know. I was just being OCD wanting to make it a perfectly square blank before shaping it which is really pointless but also seemed pretty harmless (incorrect!). So yeah I'm going to try the belt sander next and it does seem like 95% of the shaping can be done there.