CNC jointer jig

[bking1836]

I don't have a jointer and have used a table saw jointer jig in the past with mixed result (typically, good on short stock, not so much on long stock). It finally struck me how to use the CNC as a jointer with a simple jig.

I used steel dowel pins for consistent registration of the jig. That and a couple T tracks and clamps, and it's ready to go. The Vcarve program is pretty simple. 3/8" downcutter leaves a glassy finish!

Is it as fast as a real jointer? No. But it's actually much faster than I thought it would be.

32178
32180

Here's the "jointer" in action on 6/4 walnut.

https://youtu.be/qwT1JJTNtb4

[coryatjohn]

I use my CNC for that same purpose all the time. I use a 1/2" straight bit for edges since the tearout is less. I use a 2" Cleaning Bottom end mill for top surfaces.

It's much better than a purpose built machine for large pieces since it scales so well. Try and get a 4x8 table top flat using a jointer. Good luck.

[bking1836]

It's much better than a purpose built machine for large pieces since it scales so well.

I agree! This is one of those situations where the extra time is totally worth it for me, especially since I have some sort of jointer disability. I just don't get good results on anything longer than 36", although admittedly I've never used anything beefier than the Rigid 6" jointer that I used to have access to.

What feeds/speeds do you use for hardwood? I played around and got the best results at 2ips and 14500rpm on the 3/8 bit so long as I wasn't biting off too much. I did full depth passes considering how little I was taking off.

[coryatjohn]

With the 1/2 straight, I use 12k and 6ips, 1/16" full depth for pretty much everything. That's my go-to FS for most woods. I adjust from there.

I have a drum sander that is a great planer. It's not as fast as a knife based machine but it is very accurate and dependable. Changing the "knives" is super cheap too. A roll of sandpaper. 19" wide...

[bleeth]

Bking:
If you are not getting good joint edges on your 6" Rigid with longer boards than 36" it is a matter of learning more about how to use and/or properly adjust it. It should do fine for most stock that will fit on your bot (8' or so)
If you are trying to use it to get a flat face on a board prior to running it through a planer then the issue is that that tool is not nearly big enough nor powerful enough to use as a professional flat bed jointer would be.
A table saw jig when built right and with enough infeed and outfeed room and support can yield a sawn straightline on virtually any length board. I straightlined 16's on a regular basis with my shop's Unisaw.

[bking1836]

Bking:
If you are not getting good joint edges on your 6" Rigid with longer boards than 36" it is a matter of learning more about how to use and/or properly adjust it. It should do fine for most stock that will fit on your bot (8' or so)
If you are trying to use it to get a flat face on a board prior to running it through a planer then the issue is that that tool is not nearly big enough nor powerful enough to use as a professional flat bed jointer would be.
A table saw jig when built right and with enough infeed and outfeed room and support can yield a sawn straightline on virtually any length board. I straightlined 16's on a regular basis with my shop's Unisaw.

I don’t have a jointer :) I used to have access to a Rigid though. I have no doubt my technique isn’t great on a jointer. I know how. I just seem to flinch or lean the wrong way. And I get tired of fine adjustments. Generally that’s what I like about the ShopBot. It does the precision work for me.

[bking1836]

With the 1/2 straight, I use 12k and 6ips, 1/16" full depth for pretty much everything.

John - do you just screw down your stock and take off 1/16" passes, or do you have some sort of jig? Or grid on your spoilboard?

[coryatjohn]

I clamp it down to an extrusion and the extrusion is bolted to the table, itself an extrusion. I have a 60x96 table and about 14" on the side are extrusions. For jointing an edge, I place the workpiece off the table, on top of an extrusion and run the 1/2 straight down the length of the board. I set the board on the extrusion by snugging it to the end mill on one end, then clamping that end, then run the end mill down to the other end, snug the board again and then clamp in several places. For some pieces, I clamp another extrusion on top of the board to hold it firmly. I have a number of 8'x4.5" extrusions that I use for hold down. They come in handy.

32191

Like you, I am terrible with a planer/jointer machine. I find the SB to be my cup of tea as it takes the skill out of the job and gets me repeatable, exacting results.

[bking1836]

I clamp it down to an extrusion and the extrusion is bolted to the table, itself an extrusion. I have a 60x96 table and about 14" on the side are extrusions. For jointing an edge, I place the workpiece off the table, on top of an extrusion and run the 1/2 straight down the length of the board. I set the board on the extrusion by snugging it to the end mill on one end, then clamping that end, then run the end mill down to the other end, snug the board again and then clamp in several places. For some pieces, I clamp another extrusion on top of the board to hold it firmly. I have a number of 8'x4.5" extrusions that I use for hold down. They come in handy.

32191

Like you, I am terrible with a planer/jointer machine. I find the SB to be my cup of tea as it takes the skill out of the job and gets me repeatable, exacting results.

That's a nifty set up! Nice. Taking the hand skill out of jobs is important for me and my success. While the CNC is one tool of many in my shop, it's the backbone of almost everything I do. My hat goes off to folks who are masters with hand planes and chisels and to those who can make a table saw do almost anything. That's just not me. I need the precision and repeatability of a CNC and tools like the Festool Domino. I'm a "dream it up in software and bring it to life on the CNC" kind of guy. After my piece(s) come off the CNC, I expect to spend time (lots actually) assembling, sanding and finishing with as little drilling/sawing/machining as possible.