Shop built 12" jointer thoughts

[Jim C Martin]

Hello All:
I'm sure most of you who look at this forum have seen Matthias Wandel's shop built 12" jointer. If you haven't seen it I highly recommend watching the youtube video.
I have been thinking about wider jointers lately. So far I have talked myself out of buying one but that doesn't stop me thinking about it. So I've been looking at the Matthias's web page and videos. I would NOT want to build one out of a small screaming planer. Also, the idea of plywood + sheet steel jointer tables doesn't set well with me.
But recently I noticed you can buy a 12" Byrd jointer cutterhead for <$700. You can also go up to 15" planer head for even less. Then I got to searching various posts to see how other people had built jointers and I came across a discussion on this very forum about using granite for the tables. So I called a local granite countertop shop and they told me that they throw 12" remnants in the dumpster. They said I was welcome to come pick up some pieces. And yes I should be able to find a couple that were 12-14" wide by 48" long. Free!
A shop built jointer with flat granite tables and a Byrd cutterhead sounds a lot more attractive to me that the Matthias builds. I'm imagining that I could adapt his plans to be slightly beefier. All that would remain would be the frame (I still have a stash of maple!), bearing pillow blocks, and a motor. Maybe some 8020 would come in handy. Should be doable for less than $1000. In my case I could recoup that by selling my DJ20.
Any comments or advice welcom.
Cheers,
Jim

[Jamie Buxton]

This may be a little difficult to believe, but granite countertop material can bend. I've watched a countertop guy flex a slab by a good sixteenth of an inch. That doesn't sound like much, but it would be major on a jointer table.

This is not to say that 3/4" granite is a bad surface for a jointer. I'm just saying you have to support it properly -- and maybe have provision in the support system to adjust the granite so it is flat.

[Jim C Martin]

Yes, I agree. I didn't mention it in the original post but I have two good sized pieces of granite here at the house. One is dead flat as far as I can measure it. The other is about two sheets of paper (0.008") out of flat across 24". When/if I go looking for remnants, I'll take a straight edge. And I'll build in some way to true the table. I'm imagining fixing some cabinet leveling bolts to the bottom with epoxy and then using tension or compression in those to true the surface. Hope that makes sense.
Cheers,
Jim

This may be a little difficult to believe, but granite countertop material can bend.

[Chuck Hart]

There are a number of machines out there with granite tables. I think the idea is not only feasible but a very good approach to solving some of the costly alternatives (buying one). I think you can support the granite with the table design and include a method for raising and lowering the tables. The mechanism that Mathias used is crude and could easily improved. The cutter head and drive mechanism is not that complicated.. Safety would be a major issue. What kind of motor do you think you would use? Weight and stability of the machine would also be big issues. How do plan on adjusting for the obvious top heavy structure? I sure would like to follow this discussion and a build if it happens.

Chuck

[Phil Thien]

This may be a little difficult to believe, but granite countertop material can bend. I've watched a countertop guy flex a slab by a good sixteenth of an inch. That doesn't sound like much, but it would be major on a jointer table.

This is not to say that 3/4" granite is a bad surface for a jointer. I'm just saying you have to support it properly -- and maybe have provision in the support system to adjust the granite so it is flat.

Are you sure that it wasn't some synthetic that looks like granite?

What you're describing is VERY difficult to believe.

[george wilson]

I don't know if the guys are working from plans or not,but the jointers seem very clever. However,as an experienced machinist,I REALLY am apprehensive about using plywood instead of proper pillow blocks to support the ends of the cutter head. If that thing came loose doing several thousand RPM,it would permanently maim the operator. It would not take much running and vibration to compress the fibers in the wooden holes,making those bearings loose in them. Any lost hunks of flesh would be gone forever. He might well bleed to death before he could get medical help. Only takes about 5 minutes if a big artery is cut. His "bolts"(just screws,really,made of hardware grade very soft steel) are VERY THIN too,that hold the "pillow blocks" down. Not a very good idea in order to save a few bucks.

I seriously doubt that trying to screw the 3 MM steel sheets down would result in a flat table. I'd rather glue those down with a proper adhesive. A screw or 3 in the middle will pooch up the steel around them,more than keep them flat.

With a few improvements like I mentioned,the jointer seems quite nice. But,I have to say that an amateur with who knows how much experience,trying to make machines for the first time is not the best,safest thing.

[Jamie Buxton]

Are you sure that it wasn't some synthetic that looks like granite?

What you're describing is VERY difficult to believe.

Yes, I'm sure it was granite. The piece I watched him bend was the bottom of the U in a U-shaped kitchen counter. The counter was made from three pieces of granite. He started by putting all three pieces in place, sitting on blobs of polyester. He adjusted the joints to flush by driving drywall screws up through the sub-top. He adjusted one joint, and at that point the other joint was non-flush at one end by more than a sixteenth. Then he adjusted the second joint until that one was flush. The first joint didn't move while he adjusted the second one. He was twisting the granite slab.

[Jim C Martin]

Thanks Chuck! My thought was to generally use the same parallelogram approach but with larger rods (drill rod perhaps) and bronze bushings. Maybe make those connecting links out of steel or aluminum, or perhaps 6/4 maple.
For a motor I was thinking to pick up a 3hp 3450rpm motor.
What are your thoughts on how would you improve it?
Cheers,
Jim

There are a number of machines out there with granite tables. I think the idea is not only feasible but a very good approach to solving some of the costly alternatives (buying one). I think you can support the granite with the table design and include a method for raising and lowering the tables. The mechanism that Mathias used is crude and could easily improved. The cutter head and drive mechanism is not that complicated.. Safety would be a major issue. What kind of motor do you think you would use? Weight and stability of the machine would also be big issues. How do plan on adjusting for the obvious top heavy structure? I sure would like to follow this discussion and a build if it happens.

Chuck

[Jim C Martin]

I totally agree about the plywood pillow blocks. I would not use those under any conditions. Commercial pillow blocks for me!
Also agree about the table design. Hence the granite table approach.
Cheers,
Jim

I REALLY am apprehensive about using plywood instead of proper pillow blocks
snip
I seriously doubt that trying to screw the 3 MM steel sheets down would result in a flat table.

[Jim C Martin]

I was able to flex my piece of Sunset Red granite enough to eliminate the 0.008" concavity across the 2ft I could measure with my straight edge. The granite is 18" wide and 7/8" thick. I didn't try to flex it more than that but probably could have.
Cheers,
Jim

Yes, I'm sure it was granite.

[george wilson]

But,is granite as flexible as plywood?

[Phil Thien]

I don't know if the guys are working from plans or not,but the jointers seem very clever. However,as an experienced machinist,I REALLY am apprehensive about using plywood instead of proper pillow blocks to support the ends of the cutter head. If that thing came loose doing several thousand RPM,it would permanently maim the operator. It would not take much running and vibration to compress the fibers in the wooden holes,making those bearings loose in them. Any lost hunks of flesh would be gone forever. He might well bleed to death before he could get medical help. Only takes about 5 minutes if a big artery is cut. His "bolts"(just screws,really,made of hardware grade very soft steel) are VERY THIN too,that hold the "pillow blocks" down. Not a very good idea in order to save a few bucks.

I've wrestled with the same concern. Some sort of reinforcement could be added at the top of the sides of the jointer to make any possible failure less devastating, I would think.

Pillow blocks would be better.

I seriously doubt that trying to screw the 3 MM steel sheets down would result in a flat table. I'd rather glue those down with a proper adhesive. A screw or 3 in the middle will pooch up the steel around them,more than keep them flat.

My Ryobi (Japanese) 6" jointer has stainless screwed to the outfeed table (a bunch of screws, maybe eight). I think later versions used fewer screws (I've seen as few as four, I think, on the same model). So possibly they didn't like the trouble of getting the stainless outfeed "cap" flat for the same reasons you note. Mine IS very flat, but that doesn't mean it wasn't a PITA sometime and somewhere back in Japan.

OTOH, I'd be a little concerned about the possibility of adhesive failing when pushing stock into the head. Any concerns there?

With a few improvements like I mentioned,the jointer seems quite nice. But,I have to say that an amateur with who knows how much experience,trying to make machines for the first time is not the best,safest thing.

I had previously thought of building one, and had sourced a Grizzly 12" wide jointer head complete with four knives. The thing is a beast, maybe 3" in D. So the first thing that occurred to me was I'd need to use pillow blocks. And I had already decided to use something more suitable than plywood for tables.

BUT, I've come to the conclusion that I don't need a 12" jointer. The more I thought about it, the more I realized that a 6" jointer was sufficient. Every time I've used wider boards for glue-ups, I've sort of regretted it as the cups that occur happen in the middle of wider boards. I'm not sure my skill level will ever get to the point where people will look at my work and say "if only he had used wider boards."

[Jim C Martin]

Of course not. Even better, it would not be subject to variations with humidity.
Cheers,
Jim

But,is granite as flexible as plywood?

[Rollie Kelly]

And just think, you could brag that you got a brand new "Martin" 12" jointer for a $1000.00.

Rollie

[Jamie Buxton]

But,is granite as flexible as plywood?

No, a sheet of 3/4" plywood is way more flexible than a sheet of 3/4" granite. But if the 3/4" plywood is the top layer of a torsion box that's several inches tall, the torsion box can be less flexible than the 3/4" granite.