Shop built 12" jointer thoughts

[Gerry Grzadzinski]

I'm in the parts gathering stage, and getting ready to embark on this project.

I purchased the plans from Matthias, but am only using them as a reference, and designing it from the ground up.

Here are the basic specs:

13" Shelix head from a Delta 22-580
2HP motor
36" infeed and outfeed tables

Current plan for the tables is 3 layers of 1/2" baltic birch, laminate in my vacuum press with epoxy, and sealed with 2 coats of epoxy. Top and bottom will be 12 gauge steel bonded and screwed to the baltic birch. I'm hoping the balanced construction should keep it flat. I'm adding an extra link to the parallelogram mechanism to provide extra support, and have added an extra pair of supports to the outfeed table.

The bearing mounts will be cut from 1" aluminum on my CNC router. They will be mounted to 1/2" steel plates, which will be screwed and bonded to the frame. The frame members will be 1-3/4" thick LVL's.

Here's a preliminary pic of the design, which I'm doing in Fusion 360.
I'll start a thread when I start construction, hopefully in a few weeks.


Pic 1.jpg

[Jamie Buxton]

..
Current plan for the tables is 3 layers of 1/2" baltic birch, laminate in my vacuum press with epoxy, and sealed with 2 coats of epoxy. Top and bottom will be 12 gauge steel bonded and screwed to the baltic birch. .

I'm pretty sure you'll want to flatten the Baltic birch core before you put the steel on it. Plywood isn't as flat as I expect a jointer table to be. You might consider adding a layer of solid lumber on both faces of the plywood core. The added layer might be 3/32" of resawn something or other. The point of it is that you can mill it completely flat, but if you try that on Baltic birch, you may go through the face veneer.

[Gerry Grzadzinski]

Do you mean "flat" flat, or consistent thickness?
My vacuum press is a frame press with a torsion box table that's been CNC machined flat. So I'm assuming it will be pretty flat, if presses top face down.
But I can see where it might be off a few thousandths.

I had planned on cnc milling the bottom, but after I do that, I'll flip it and take .01" off the top as well to get two flat face that are parallel. Face veneers on batic birch are usually at least .04" thick, so it shouldn't be an issue to flatten both sides without going through the faces. Even if it did, I don't think it would matter with 3 layers of ply and 1/8" metal skins top and bottom.

My biggest concern is the flatness of the steel. There's not a lot that I'll be able to do with it if it's not. It looks like only about 10 of these have been built, and I haven't read any issues about the steel, so I'm hoping it's OK. If not, then I may explore the granite option. I'm hoping that I don't need to.

[Jamie Buxton]

Do you mean "flat" flat, or consistent thickness?
My vacuum press is a frame press with a torsion box table that's been CNC machined flat. So I'm assuming it will be pretty flat, if presses top face down.
But I can see where it might be off a few thousandths.

I had planned on cnc milling the bottom, but after I do that, I'll flip it and take .01" off the top as well to get two flat face that are parallel. Face veneers on batic birch are usually at least .04" thick, so it shouldn't be an issue to flatten both sides without going through the faces. Even if it did, I don't think it would matter with 3 layers of ply and 1/8" metal skins top and bottom.

My biggest concern is the flatness of the steel. There's not a lot that I'll be able to do with it if it's not. It looks like only about 10 of these have been built, and I haven't read any issues about the steel, so I'm hoping it's OK. If not, then I may explore the granite option. I'm hoping that I don't need to.

Yeah, I mean flat, not consistent thickness. But with a CNC mill, you can make it flat.

If you have CNC access, couldn't you use it to take out any variations in the steel after you've epoxied it to the plywood core?

[Gerry Grzadzinski]

I have access to an industrial router, but it's not suitable for flattening a steel table. It would really need to be ground flat on a grinder.
Grinding large flat surfaces requires coolant (I think) which would not agree with the wood core. It also wouldn't be cheap.
https://www.youtube.com/watch?v=XqsrFuuhqk8

[Jamie Buxton]

I have access to an industrial router, but it's not suitable for flattening a steel table. It would really need to be ground flat on a grinder.
Grinding large flat surfaces requires coolant (I think) which would not agree with the wood core. ..

You were worrying about whether the 12 gauge steel is going to be a uniform thickness. So I was thinking you'd only need enough CNCing to fix that -- maybe a few thousandths here or there? That's a smaller job than the job in your linked video.
A slightly different approach would be to use aluminum cladding instead of steel. You can cut aluminum with carbide wood bits. So the few thousandths of flattening really could be done on a CNC woodworking router system. Of course, steel would be more wear-resistant, but maybe that's not a big issue.

[Art Mann]

The variance in the thickness of the steel is utterly irrelevant in comparison to the variance you are going to get trying to build a precision machine out of plywood. Even high end commercial jointers will have a few thousandths of variance over the whole table. This isn't steel we are machining. It is wood, for heaven sake.

[Gerry Grzadzinski]

To clarify, I wasn't talking about the thickness of the steel, but rather how flat it actually is, as I don't know if it will be possible to straighten a warped or curved piece of steel.

[Jamie Buxton]

To clarify, I wasn't talking about the thickness of the steel, but rather how flat it actually is, as I don't know if it will be possible to straighten a warped or curved piece of steel.

So maybe you should use thin steel. In your design, it is really a wear layer, and doesn't have to be thick. So you laminate up the plywood core, mill both faces flat and parallel, and then epoxy steel veneer to both faces. Maybe the steel is only thirty thou thick or the like. It is thin enough that the vacuum press can take out any non-flatness as it presses the steel to the core.

[Art Mann]

The machines I have read about all use a thin sheet metal lamination. The metal is thin enough to conform to the plywood.

[Marc Burt]

Just wondering if anyone has made progress on one of these lately.

[Kevin Jenness]

I cease to be amazed by the ingenuity expended on this subject. It is not that hard to find a decent used 12" jointer engineered by actual engineers to flatten and straighten wood for a couple thousand Ameros. There are good reasons why jointers have been built for many years of cast iron rather than countertop scraps or plywood and sheet steel. What is the point?

[Art Mann]

I think the real appeal of such a project is to accept the challenge and achieve such a difficult technical task. I don't think it is really about money. Considering the time spent, it would probably pay less per hour than most folks would be willing to work for.

[Gerry Grzadzinski]

What is the point?

I don't have $2800 for a 12" Grizzly, but I can afford the 13" jointer with Shelix head that I'm building for $700.

While it seems like a majority of the members here have bottomless pockets and tens of thousands of dollars in machinery, there are a lot of woodworkers who don't.

[Art Mann]

I think it would be very optimistic to assume the project would be designed and complete and all the required calibrations done in less than about 80 hours. That is 80 hours I could spend doing paying work. Couple that with all the premium grade plywood, structural hardwood, sheet metal, fasteners and other materials you will need and the price starts to look more like the price of a jointer/planer combination machine like I have. In order for this to be a positive financial endeavor, you are going to have to assume a low value for your time and accept the obvious limitations of a machine made out of plywood and salvaged lunchbox planer parts.