Glue joint router bit

[lcm1947]

Am I correct in thinking that if you used a one bit glue joint bit ( as apposed to a two bit set ) that your boards wouldn't have to be that perfectly jointed? Wouldn't this bit itself insure that the boards would be jointed enough to do a table top glue up? I may be all wet but it sure looks like the bit would kind of insure this. If this is correct it sure would be great for us no jointer guys.

[eddy merckx]

Hi Mac

I could be way off here, but I don't see how a glue joint bit would help. A jointer makes one edge of a board dead flat. If the edge isn't flat, you'll probably get a gap at the glue joint. It seems to me that a router bit would just follow the edge that you already have. So if you have a gap when you join two boards, you'd still have it after machining a glue joint. Furthermore, the long grain sides of a board should glue up plenty strong enough without a special joint.

If you have a tablesaw, you can make or buy an inexpensive jig to rip a straight face on your boards. I've seen them at Sears.

If you have a router table, you can joint your boards with a straight bit and some laminate on one side of the fence, like a sideways jointer.

Both methods reportedly work OK, although I haven't tried either.

Eddy

[drumpriest]

Actually, if you have a router, you can edge joint boards. Buy a pattern bit (bearing on top), or a flush trim bit (bearing on bottom), and a 5$ MDF shelf from the BORG. Clamp the shelf and board together and trim away. When you are done you'll have a true edge for gluing.

[footprintsinconc]

hopefully i understood your question correctly, then the my opinion is as follows:

if you remember niki's post about "joining with router", essentially what you are doing by using a flush router bit is getting a 90 degree or almost 90 degree (if your router bit isnt perfectly perpendicular to the table), when you run one board face up and the other face down and then join them, you should get no gaps.

if you now substituted the flush router bit, with the glue joint bit, i think you would follow the same procedure. that should give you the interlocking for your joint.

good luck and regards,

[Tom Hintz]

You can do a very minor amount of "straightening" with a glue line bit but the key is "very minor". And, this has to be done on a router table with adjustable fence halves where you can shim the outfeed side slightly forward of the infeed face.
The best way is to joint the board first to get a straight edge and then use the glueline bit.
Incidentally, glueline bits are to be used in a router table only. I don't know of any manufacturer that recommends using them in a hand held router. These bits are too big and doing too much cutting to be controlled safely by hand.

[gjat]

I think lcm is asking a different question then what was answered..

A fitted glue joint would be more forgiving because of the increased surface area for the glue joint, plus, the tongue/groove would eliminate any 'gap' all the way through if the the two faces weren't perfectly paralell.

You seem to be correct, lcm, but though you wouldn't have a "gap", you would still see the joint, but it would be structurally sound. Depending on the style of furniture, that may not be an issue to you. I personally like to think I build 'Rooms 2 Go' fruniture, not 'Ethan Allen' furniture, but at K-Mart prices.

[LarryG]

I think all the replies are correct, but in different ways.

Edge-jointing a board accomplishes two things, in theory: it makes the edge dead straight, and it makes that edge of the board perpendicular to the two adjacent faces.

WRT making the edge straight, a glue joint bit doesn't really change anything. It breaks the overall thickness of the board down into thinner segments but the one on top, the one that will be visible, still needs to be dead straight for the best appearance. IOW the thickness of a board is immaterial in terms of whether it should or should not be edge-jointed for straightness.

WRT making the edge perpendicular to the faces, a glue joint bit does make that more or less moot since it forms a T&G arrangement with more surface area. As gjat notes, it also eliminates any concerns about having a visible gap all the way through two adjacent boards.

[scorrpio]

If board edge is dead straight but not square to the face, glue joint bit will correct it.

If edge has a bow to it, you need to joint theedge straight, or you will simply end up with a glue-joint profiled bowed edge.

[lcm1947]

Ok thanks guys. I was kind of hoping but sounds like these bits are not the answer to my solution. I know of the other methods but thought I'd try these. Thanks again. At least I didn't spend my $30.00 to find out the answer. Appreciate it.

[niki]

Hi Mac

Sorry for so late reply but I did not want to advise before I make it myself and see how it works.

This method depends on a long straight edge (SE), when I'm saying long, I mean that all the length of the board must be supported before hitting the bit and after leaving the bit.
In simple words, if your board is 3 feet long, the SE must be at least 6 feet long.

About SE, I saw here a long (100") SE that the guys of the "wall-to-wall" carpeting are using (it has an apex on one side), as a guide to cut carpet. I checked it against another one and found them very straight.

Hope it helps
niki

[niki]

[niki]

[niki]

[lcm1947]

Hey thanks Niki for going to all that trouble to help me out and certainly no problem on you getting back late. Late isn't even a factor so you were't and if it were I'd never say anything. Like the old saying goes " don't look a gift horse in the mouth". I'm a firm believer in that saying. I just appreciate you getting back at all. Well, it looks like a pretty easy and neat way to joint boards. I'll have to do some searching to find a 8 ft board (SE) then as my table top is supposed to be 48" long. I'll call around to some carpet places and see what they use. Thanks for that tip too. That sure is a nice looking SE you got there. I've noticed it before in some of your posts but didn't comment on it then. What is it anyway? Also I just have to ask, what is that 2x2 that's clamped on the other side of the bit for. Just to catch the sawdust?

[LCHIEN]

No offense intended to Niki, but that's not my favorite way to use a router, I personally would regard that as a bit dangerous.

You are feeding the wood between the router bit and the fence, that's potentially asking for a bad kickback. I see he is feeding the wood with the router bit turning into the wood. Because the standard way most people are taught is to bury the router bit in the fence, he is feeding (relative to the table, not to the bit) opposite most table routing jobs.
Anyway the danger is that if you let go while feeding, the workpiece might get grabbed by the bit and jammed between the fence and bit and flung in a dangerous manner.

The way I've seen most all router jointing is to bury the bit in the fence within an opening, stick the bit just proud of the right side (feed side) fence by the amount you wish to trim, and then have the left (outfeed) fence be flush with the cut edge of the bit. That way if you ever pause or stop or move the wood away form the fence, it will be safe, and you can resume by moving the wood back to the fence.

I see two potential advantages to Niki's setup - its easier to setup and the straight edge is longer than most fences, but I think the danger factor is there.

Anyone else see it that way?