End Grain to End Grain - Any Ideas?

[Snap Marc]

I am working with large pine frame-moulding strips come to me from my supplier in 108" lengths. Often for work, I need to join them to make them longer. Occasionally I need them as long as 144" or 156' or even longer.

Regular doweling jigs don't work. They can't clamp to the workpiece due to the rounded bevel. and my wood's asymmetry

So, I improvised. See below. I cut a small piece of the bar stock and made a simple setup block that has two holes and can be applied to either end of a board. My though was to use the piece as a drill guide and the just clamp to to one end, drill, then flip the template onto the adjoining workpiece and drill the mirror image.

I tried it today with mediocre results. Also, the drill bit chewed up the soft pine pretty easly.

I made a hardwood "corner reference" jig out of some hard maple. Seems better, but not perfect..

I have also looked at the Festoool Domino joiner. Looks about perfect other than the price. They're really expensive but probably worth it.

Any help would be appreciated.

Here are some pics to look at. I need this connect quicli

Thanks in advance,
Snap Marc

[cray-]

Does it have to be a butt join? Why not use a half lap and fix it from the back with a couple of dowels or glue & screw/nail?

I see finger jointed mouldng strips at the local big box but I imagine this would be far too much manual labour for a simple moulding.

[leehljp]

Finger joints would be the best, IMO. It takes a little adjusting and experimenting but you are already doing that. You have already run into the problem presented with dowells. Dowels do well for some joints but straight joints like you are trying are hard to come by without considerable experience - if you are looking for perfect non-moving joints.

[BadeMillsap]

Can you use a mechanical fastener like
http://www.rockler.com/tite-joint-fastener

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[Snap Marc]

Does it have to be a butt join? Why not use a half lap and fix it from the back with a couple of dowels or glue & screw/nail?

I see finger jointed mouldng strips at the local big box but I imagine this would be far too much manual labour for a simple moulding.

A half lap is not a bad idea. I would just need to get a table saw set up at work. I have a beauty at home. I guess it doesn't even have to be a dado stack, it could be done with repetition cuts on a single kerf. Or would you suggest a router table? I guess with a router table I could do finger joints too.

Another option I have would be a long scarf joint and glue.

These pine bars are for stretching canvases around them. We build the frame and then staple canvas around the bars with great tension, so whatever the joint is, it must be very strong.

Which do you think would be stronger? Half-lap and glue, or finger joints? These bars do come from the factory with existing finger joints, but they are mass produced on very industrial machinery for perfect finish.

Great suggestions all around and thanks to you all. Any other ideas would be appreciate.

Marc

[Snap Marc]

That's a cool piece of hardware for sure. I don't think it would endure the pressure the stretched canvas would exert on the bar. I could see it sort of imploding. But i have never see that before and I will remember it for the proper application. Again, thanks for taking the time. I think a half lap or a finger joint might be the way to go. I'm looking into it.

[LCHIEN]

Looks like a half lap would be the ticket.

You could do it either way (direction) - half lap parallel to the face with the feature, or half lap perpendicular.
The latter would seem to be easier to do.

[trungdok]

These pine bars are for stretching canvases around them. We build the frame and then staple canvas around the bars with great tension, so whatever the joint is, it must be very strong.

I'm a bit slow on this. You are wrapping canvas around the molding? Or are you wrapping canvas around a frame, then put the molding on top?

If it's the first, then why? If it's the second case, then I don't think you need to worry about tension.

[atgcpaul]

So whatever joint you do, it will be covered by canvas? Additionally, it's important that you can do this in the field, right?

[Black wallnut]

I would think a half lap as well.

[poolhound]

I would go for a half lap reinforced with a couple of dowels going through both halves. Under stress I would bet the moulding would break before the joint does.

[capncarl]

I've pieced together shoe mold and chair rail using a scarf joint with good enough success. The problem with all joints is handling a long board on a table saw or route table. All I have ever used was the table saw with a sled and blade set at a 45. Glued and pin nailed together. Mr Google says this about the scarf joint.

In woodworking, there are two distinctly different categories of scarf, based on whether the joint has interlocking faces or not. A plain scarf is simply two flat planes meeting on an angle relative to the axis of the stock being joined, and depends entirely on adhesive and/or mechanical fastening (screws, bolts, etc.) for all strength. Hooked, keyed, and nibbed scarfs are some of the many example of interlocking scarfs, offering varying degrees of tensile and compressive strength, though most still depend on mechanical fastening to keep the joint closed.

The plain scarf is not preferred when strength is required, so it is often used in decorative situations, such as the application of trim or moulding. The use of modern high-strength adhesives can greatly increase the structural performance of a plain scarf.

[durango dude]

Thinking out loud ---- maybe a dumb idea - I don't know.

Would it work to cut the pieces at an angle with a miter saw - and then join with a biscuit?

[EarltheWoodbutcher]

I used to make kayaks and when I needed long, strong pieces to get out to 16' or 20' I would use a scarf joint. They are stronger than the wood. Done tightly you won't break one. I can guarantee it. And you can add dowels to it to make it even stronger, but I don't think are usually necessary. They have been used in the boating industry for eons, even for the keel where massive strength is needed.

[leehljp]

I used to make kayaks and when I needed long, strong pieces to get out to 16' or 20' I would use a scarf joint. They are stronger than the wood. Done tightly you won't break one. I can guarantee it. And you can add dowels to it to make it even stronger, but I don't think are usually necessary. They have been used in the boating industry for eons, even for the keel where massive strength is needed.

Scarf Joints - that is what the joints are on the crown moulding in our 80 year old living room and dining room.

Scarf Joint: Here

Thanks Earl, for the reminder.