Conical Disc as Jointer

putttn · Post by **putttn** » Sat Sep 22, 2012 10:11 pm

I've read that the Conical disc is a good substitute for a Jointer on material that burns up Jointer/Planer knives? Do any of you use the Conical disc to Joint and what's your opinion?

algale · Post by **algale** » Sun Sep 23, 2012 5:45 am

Yes it will edge joint (sand) things like plywood and MDF which would dull your jointer knives. It works quite well but be advised the maxim depth of cut is only about the thickness of the sandpaper installed on the conical disc so you may need to make quite few passes depending on how bad the edge is that needs to be jointed. There's also a Sawdust Session where Nick shows how to set the conical disc up in drill press mode to use it to sand to a precision thickness on the face of a board although I've never tried it myself.

Getting back to edge jointing/sanding, you need to either have one edge of the work piece already straight to ride the fence or you need to attach a temporary straight edge. There are several methods for doing so. The general idea is to take a thin strip of something wider than your work piece and with a known straight edge (the factory edge of a piece of hardboard or plywood works) and attach the work piece on top of it with the edge to be jointed slightly overhanging the strip. The straight edge then rides the fence and the overhanging edge of your work piece can be jointed/sanded. If you will do this often or don't want to put holes in the work piece to attach it to the temporary straight edge, you can build a jig with a couple of toggle clamps to hold the work piece to the straight edge so you don't need to put holes in the work piece. Hot melt glue I am told also will work for a temporary bond without damaging the work piece.

JPG · Post by **JPG** » Sun Sep 23, 2012 12:35 pm

algale wrote:Yes it will edge joint (sand) things like plywood and MDF which would dull your jointer knives. It works quite well but be advised the maxim depth of cut is only about the thickness of the sandpaper installed on the conical disc so you may need to make quite few passes depending on how bad the edge is that needs to be jointed. There's also a Sawdust Session where Nick shows how to set the conical disc up in drill press mode to use it to sand to a precision thickness on the face of a board although I've never tried it myself.

Getting back to edge jointing/sanding, you need to either have one edge of the work piece already straight to ride the fence or you need to attach a temporary straight edge. There are several methods for doing so. The general idea is to take a thin strip of something wider than your work piece and with a known straight edge (the factory edge of a piece of hardboard or plywood works) and attach the work piece on top of it with the edge to be jointed slightly overhanging the strip. The straight edge then rides the fence and the overhanging edge of your work piece can be jointed/sanded. If you will do this often or don't want to put holes in the work piece to attach it to the temporary straight edge, you can build a jig with a couple of toggle clamps to hold the work piece to the straight edge so you don't need to put holes in the work piece. Hot melt glue I am told also will work for a temporary bond without damaging the work piece.

????????????

SS touts it as 1/8" or more?

greitz · Post by **greitz** » Sun Sep 23, 2012 12:59 pm

I think the maximum depth of cut is largely dependent upon the speed at which you feed the workpiece through, and the coarseness of the sandpaper. If you push too fast, the sandpaper will get ripped off the conical disk (says the voice of experience). Remember you're sanding off the material, not cutting it off, and so you need to go slow.

Gary

algale · Post by **algale** » Sun Sep 23, 2012 8:28 pm

JPG40504 wrote:????????????

SS touts it as 1/8" or more?

At the 7:02 minute mark of this video, http://www.shopsmithacademy.com/SS_Arch ... Sander.htm, Nick states don't try to take off more the 1/64th at a time with the conical disc or the sandpaper will be impacted with sawdust and it won't work properly.

JPG · Post by **JPG** » Sun Sep 23, 2012 11:23 pm

algale wrote:At the 7:02 minute mark of this video, http://www.shopsmithacademy.com/SS_Archives/SS101/SS101_ConicaL_Sander.htm, Nick states don't try to take off more the 1/64th at a time with the conical disc or the sandpaper will be impacted with sawdust and it won't work properly.

Scroll down for the 'touting' previously referred to.

http://www.shopsmith.com/ownersite/catalog/sn_conical_sanding.htm

algale · Post by **algale** » Mon Sep 24, 2012 12:27 am

JPG40504 wrote:Scroll down for the 'touting' previously referred to.

http://www.shopsmith.com/ownersite/catalog/sn_conical_sanding.htm

Seems there's a conflict! Here's a second Nick video stating at the 11:12 mark not to take off more than the thickness of the grit, which he says is 1/64th to 1/32nd. http://www.shopsmithacademy.com/SS_Arch ... anding.htm

JPG · Post by **JPG** » Mon Sep 24, 2012 12:59 am

algale wrote:Seems there's a conflict! Here's a second Nick video stating at the 11:12 mark not to take off more than the thickness of the grit, which he says is 1/64th to 1/32nd. http://www.shopsmithacademy.com/SS_Archives/SS114/SS114_Thickness_Sanding.htm

For 'surface' sanding I would totally agree! I have done that(made a 'tapered' sled by sanding to the disc angle). Aggressive material removal is not recommended by me either.

I do not agree for narrow edge sanding/jointing. Very aggressive stock removal is possible. For fine grit however, a lighter feed is indicated.

Who adjusts the jointer for an 1/8" cut anyway?:D

keakap · Post by **keakap** » Wed Oct 03, 2012 8:36 pm

JPG40504 wrote:For 'surface' sanding I would totally agree! I have done that(made a 'tapered' sled by sanding to the disc angle). Aggressive material removal is not recommended by me either.

I do not agree for narrow edge sanding/jointing. Very aggressive stock removal is possible. For fine grit however, a lighter feed is indicated.

Who adjusts the jointer for an 1/8" cut anyway?:D

Everybody's right.
Keep the paper from clogging by sanding no deeper than the thickness of the grit.
But when you're removing stock you aint gonna be using 120 grit paper.
And heavier grits don't clog (within reason).
1/8" removal w/ 60 grit paper is so fast it's almost scary, and it won't clog or overheat (again within reason).
Fine sanding w/ 150 grit is slower, but you're takin off a few thou, not 125.