How to do this compound angle with Domino

[mbira]

Hi folks,
I am borrowing a Domino from a dealer for a couple days to see if it will do what I need.  I have been playing with it here, but I can not figure out how to do this.  Pictures are worth 1000 words so hopefully that will clarify what I'm doing.  I'm trying to do two blind loose tenons so that the long piece with join cleanly to the end piece at a 3.5 degree angle.  I can't tell how I would be able to both do that angle and have the piece be flush with the and piece.  I was planning on doing two #8 400mm tennons. 

Any suggestions on this would be great.  I have all the accessories here. 

I was thinking that it may be easiest to just shoot the tenons through straght into the long pieces and then do the 3.5 degree angle on the end piece, but then I don't know how I will be able to accurately place those holes...

 

[nclemmons]

Align the pieces in your drawing and make a mark across the two pieces where you want your domino to go.  So likely centered on the 2 25/32 dimension.

Then you can plunge into the end of that piece with the domino face folded down and flat to the long piece.  Make the piece overhang the end of the bench, so that the Domino does not bottom out on the bottom of the workbench.  Use the alignment mark from the first step to align the Domino with that mark in the center.

Then reverse the Domino and plunge into the end bracket, again aligned to the mark that you made. with the fence overhanging the side.  By referencing the common edge with the fence and plunging into the shared surface on both with the Domino flat to that plunge surface, you don't have to worry about the angle.  Both mortises will be perpendicular to the face you want to have dominoed.

Hope that helps.

neil

 

[mbira]

Thanks for the reply, Neil.  That doesn't line up the face of the long piece with the edge of the end piece correctly.  There is an error of a few mm because of the 3.5 degree angle on the edge of the end piece.

 

[Clweed]

Try adjusting the width of one of the mortises.

 

[mastercabman]

I don't understand what the big deal is
Put the fence on the edge of the end piece and the side of the long pieces

 

[mbira]

The big deal (for me) is that 3.5 degree angle.  I set the fence to 90 for the long piece and then set it for 3.5 degrees for the end piece and it lines up...pretty well. 

But not as well as when I do it by hand and use dowels. 

It's a real small face on that end piece to get the 3.5 degree to register perfectly.  I'll keep trying with looser width and see if that helps. 

 

[tbellemare]

Let's get together, J...

I think we can come up with a repeatable method.

Tom

 

[mastercabman]

The big deal (for me) is that 3.5 degree angle.  I set the fence to 90 for the long piece and then set it for 3.5 degrees for the end piece and it lines up...pretty well. 

But not as well as when I do it by hand and use dowels. 

It's a real small face on that end piece to get the 3.5 degree to register perfectly.  I'll keep trying with looser width and see if that helps.

I guess I'm not understanding the drawing
Where is it that you want to put the domino?
Are you trying to connect the end  piece with the long board?

 

[mbira]

Are you trying to connect the end  piece with the long board?

Mastercabman, that's correct.  Note the angles on the drawing-that's what makes it tricky (for me).

As I said, I am just brand new and checking this seemingly awesome machine out.  Hopefully I can get it to do what I need because it certainly saves time! 

Tom-I'd be open to that.  Not sure if you have any time to swing by the shop in the next few days?  I'm about 3 blocks from ya...

 

[Rick Christopherson]

Don't think of it as a compound angle and it will be easier to see. Any mortice must be plunged perpendicular to the FACE of the joint, regardless what angle may be involved between the pieces. If you were to plunge at any other angle than 90 degrees, it would require your tenon to be bent (like a V or L or >).

 

[mbira]

I get it.  But in any case, I am getting about .5 mm off from being completely flush. 

With the domino, should two angled pieces be able to join perfectly, or is .5 mm considered acceptable?

When I do this by hand, I expect to be able to clamp the pieces such that I can't feel the joint with my finger.  Can I expect the same from a domino?

 

[downtheroad]

From what I understand, clamping a fence to the face of the shorter piece for registration, placed back from the end the thickness of the long piece should work.

 

[MaineShop]

As an older carpenter that I used to work under would say, "your over thinking the hill."

The 3.5 degree joint doesn't matter if it is 3.5 degree or 90 or what ever, the tightness of that joint will have nothing to do with the domino and everything to do with your ability to put that matching bevel or miter cut on the end of the long piece. If you make that miter cut correctly the joint will be tight.

Get the joint right before you worry about getting the domino in it.

You have a 3.5 degree bevel on the edge of the end piece, you cut a corresponding 3.5 degree miter cut on end of the long piece at your desired length. now the two faces should meet up nice and flush.

Once you have that joint fitting tight then put the domino in. In this instance I would make a pencil mark on the outside of the joint marking the center of where I wanted my domino. Then I would clamp the pieces down separately exposing the two faces to be joined. Since it would be a royal pain to try and work with 3.5 degrees with the flip down fence on the domino, I would add or subtract from 90 degrees for the angle so that I could use the fence at roughly 90 degrees for example 86.5 or 93.5 degree depending on which side of the board you had facing up when you clamped it down.

And no 5mm would not be acceptable for any joint, I don't think you would get any birds with a birdhouse that had that kind of draft.

EDIT: Ah sorry just reread that and saw that you said .5 mm not 5mm. My bad, disregard that last bit. I could see the joint being a bit off if it is the last of the four joints you are putting together. If you already drove the other three home and tightened them up I could see the last one being a little off. One of the great appeals of the domino and why I have it in my shop is that for funky joints like this it is very good at dry fitting where you can put the whole piece together and see how it fits and still tap it back apart to adjust and trim cuts before you get the glue involved.

Adam

 

[mbira]

The joint is good.  Everything fits as it should before I try the domino.  From what I can tell, you are saying even .5mm off is not acceptable which is good to hear.  Hopefully I can get this working correctly.  I believe the error is happening when I am having to hold the domino up to to the end piece.  It seems like a little too much play when plunging that.  Maybe if I try and flip the domino and mark the wood and do it without the fence hanging off the edge with that 3.5 degree angle then I'll have better luck.  I'll try that tomorrow.

 

[Grasshopper]

If I am seeking a flush joint, and can reference off that flush face, anytime my joint is less than flush is operator error.  I've found making a small jig to clamp your workpiece (or otherwise getting it clamped well) before making mortises, and taking my time with the plunge while making sure the domino stays on the reference face…the joint comes out very flush.  If I make a mistake and am off by a hair, it is easy to sand the joint flush.  My two cents.

 

[Mismarked]

If the outside edge of the joint is not exactly flush, the problem might be that the height adjustment of the Domino is not set exactly in the middle of the thickness of your 1" thick wood.  If that is the case, your mortise into the edge of the long piece will be slightly higher than .5", and your mortise into the face of the short end piece will be slightly more than .5".  If it is exactly in the center, it doesn't make a difference which side of the long piece you use as a reference face for the Domino500, but if it is slightly off, it does make a difference, and if you flip the board over it will be perfectly flush.  So, you could either adjust the height setting, or you could try turning the long piece upside down and then cutting, and see if the joint is flush.  Probably best to try this on some scrap 1" stock.  Cut a mortise on the edge of the scrap piece, then flip the piece over and cut a second mortise, and then try fitting that scrap piece to your end piece to see if one of those mortises is off but the other is exactly flush when you fit it to the end piece.  I was having the same kind of problems when I first started using the Domino a couple of months ago.

 

[mbira]

Well-looking at this for the second day, I can see what the problem is.  There is no way for me to mortise the long piece from the outside(where I would scribe the pencil mark) and have both the fence and the face of the Domino touching the wood.  The fence would need to be able to go to 93.5 degrees to do that.

So the option is to either:
1) flip the piece and get the face flush and not have a pencil mark to reference both pieces.
2) Plunge parallel to the long piece and then have to do the angled mortise into the face of the end piece.

The first way doesn't let me have a quick and repeatable way to reference things to line up correctly.
The second way leaves me hoping that I can balance the face of the domino with the fence the only thing referencing that angle and hoping the domino doesn't move while plunging.

As far as I can tell, the only other way to do this is to not reference the edge and use a pencil mark to line the domino up to on the end piece. 

No matter what, I don't see this consistantly giving me a completely flush joint every time.

Neither method fills me with confidence.

 

[mastercabman]

Mbira
How about some pictures of what you are working on
From. Side and top view

 

[waho6o9]

Plunge the mortice first

Cut the angle and insert Domino

Mark the mating piece and plunge the Domino.

Practice on scrap and you'll get the hang of it.

 

[Mismarked]

So the option is to either:
1) flip the piece and get the face flush and not have a pencil mark to reference both pieces.
...

The first way doesn't let me have a quick and repeatable way to reference things to line up correctly.

I think if you can try the first option and get the angle right and the face flush, aligning the parts (vertically) will not be a issue even without a pencil mark on both pieces, if you do what Clweed suggests and use wider mortises on one of the pieces that would let you adjust the alignment of the two pieces when you assemble and glue them.