Jointer vs. Conical disk?

[forrestb]

You asked about a planer sled for jointing. I tried that but it is not very good for thin boards since it will tilt the board unless you are really careful. Heavy boards are apparently no problem.

I good the torsion box I built for that and adapted Nick Offerman's approach in a recent FWW. I did so after watching Spagnuolo's video on flattening his new workbench (http://www.thewoodwhisperer.com/videos/ ... echniques). I used the same Amana bit. I have a pdf on Offerman's article.

[ATTACH]25547[/ATTACH]

I have a large piece of BB Plywood on top of the SS. The torsion box rest on it and is held in position by scrap wood temp screwed to the ply.

The keys are 1) to use shims so the board doesn't rock and a means of holding it there (I used drywall screws in wooden brackets) and 2) to use a vernier caliper to set the height of the platen on which the router runs to the same height on the four corners of the slot.

What is shown is a 5 ½ inch piece of hard maple.

It worked out very well and went from there to the thickness planer. I now how a proven (to me) system to flatten boards up to 10 inches wide. If I were doing a huge piece like Offerman, I would use his more robust system

Forrest

[Gene Howe]

Thanks Forrest! Could you somehow post Offerman's pdf here?

Clipped I have a pdf on Offerman's article.

Clipped
Forrest

[BuckeyeDennis]

Yes. So?

Yes for small pieces. I made a jig to do that with the table set to '0'. Nick got me to try it with that sawdust session.

Not for the faint hearted.

So, I was fishing to see if Charlese could tell us if his disc-jointed edges were also "wavy" in the linear dimension -- this would tend to either confirm or refute the table-flex theory.

[forrestb]

but it is way too big.

The article is in Issue 222 Nov/Dec 2011 (hhmmm, is that considered recent?)

Forrest

[BuckeyeDennis]

You asked about a planer sled for jointing. I tried that but it is not very good for thin boards since it will tilt the board unless you are really careful. Heavy boards are apparently no problem.

I good the torsion box I built for that and adapted Nick Offerman's approach in a recent FWW. I did so after watching Spagnuolo's video on flattening his new workbench (http://www.thewoodwhisperer.com/videos/ ... echniques). I used the same Amana bit. I have a pdf on Offerman's article.

[ATTACH]25547[/ATTACH]

I have a large piece of BB Plywood on top of the SS. The torsion box rest on it and is held in position by scrap wood temp screwed to the ply.

The keys are 1) to use shims so the board doesn't rock and a means of holding it there (I used drywall screws in wooden brackets) and 2) to use a vernier caliper to set the height of the platen on which the router runs to the same height on the four corners of the slot.

What is shown is a 5 ½ inch piece of hard maple.

It worked out very well and went from there to the thickness planer. I now how a proven (to me) system to flatten boards up to 10 inches wide. If I were doing a huge piece like Offerman, I would use his more robust system

Forrest

That's a neat setup. I had watched the Wood Whisperer bench-flattening video before, but it never occurred to me to use a router sled for smaller stuff.

I did try something similar though, using the old red Shopsmith version of a Wagner Safe-T-Planer. I had a half log from which I wanted to cut a bowl blank, but the radius was too large to fit through the bandsaw. Plus I needed a flat on it for future faceplate mounting. So I mounted the rotary planer to my Mark V in drill-press mode, and temporarily mounted the half-log to a baseplate using hot glue, flat side down. Then I just slid the baseplate around on the Mark V table to make planing passes. It worked quite well, except for throwing bark chips everywhere.

For flattening boards, I've been using this planer-sled technique with great success. Super quick and easy. Hot glue is used to form instant shims, and it makes a nice rigid sandwich out of the workpiece and the sled base. So I would expect this technique to solve the thin-board problem. Putting masking tape down before applying the hot-glue shims makes "sandwich" disassembly and cleanup easy.

[fitzhugh]

I saw a video recently about sleds and planers. Used shims and hot glue to secure the piece on the sled. I think I'll stock with hand planes for that for now though.

OP here, reading w/interest but not much to add, but don't take that as meaning all this isn't helpful for me too.

Oh yeah, discussion above about jointing two boards for glueing w/out worrying about 90 degrees... It seemed unclear to some. When hand planing or equivalent you place the two boards face to face with the edges to be joined both facing up (for hand plane with jointer plane). Joint nice and really straight but not too worried about angle. When you lady them out the two joined edges have complementary angles. Errors cancel out. Usually when jointing a single board I use a cambered blade, doesn't work well here though.

I recently did this on two 3 inch thick 66 inch long (13 wide) boards for my bench top. Even worked well there, though with more attention and manual correction than mm narrow boards.

Not sure of that helped clarify, offer if clarification was needed.

Off to have dental surgery. much rather make shavings.

[fitzhugh]

Here's the sled video
Joint with a thickness planer from American Woodworker
Haven't tried it myself yet.

[fitzhugh]

NOW I'm off to the dentist.




... Unless I find some other distraction first [looks around hopefully].

[forrestb]

Thanks for the link. I did not think about using hot glue once the shims were in place. I think I will try that next time since I believe it will take less time. Infeed/outfeed support with SS will be tedious.
Forrest

[charlese]

Very interesting! As I said earlier, I played with the conical disc for edge jointing, but did not get so far as an actual glue-up.

If I understand correctly, the angle you got on the edge was not consistent, even on the same workpiece. I'm wondering if table flex could be the root cause. With the table set at 4 degrees (or whatever it is), you obviously can't be using connector tubes to lock it to the extension table. This would leave the table somewhat springy, and the force from the sanding disc would deflect the table. Not to mention the pressure that you apply to the workpiece to hold it flat against the table and fence. I would expect the center of table rotation to be beneath the trunion, where it would change both the angle and the centerline of the edge....

I don't think it is caused only by table flex. It is important to get the table exactly 90 degrees from the sandpaper on the disk. This is an almost impossible task, especially if there are differences in the thickness of the grit and if the paper is perfectly smoothly applied to the disk.

Another strong possibility is variations in the speed of movement of the workpiece. As we all know - if a slower pass is used, more wood will be sanded. If you want to test this, get a sample workpiece that is just barely touching the sanding disk - pass it along and let it stall for a few seconds at one spot.

Any irregular speeds of the workpiece will cause an irregular edge. It is also what I call wavy when the 90 degree angle between the table and the disk is off a small amount. Parts of the edge where it joins a face will show the irregularity.