Faces of thin pieces are not flush on DF-500

[Festdewalkita]

I will be attaching hardwood to cover the edge of plywood.  The pieces are notional 3/4" ply wide (roughly 18mm) by 3/4" deep.  I was practicing on thin strips of plywood on the off-chance things didn't go well.

I'm plunging like I've seen done in countless videos--following the 4 rules of Domino-ing.  I'm getting crooked faces:
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It's outside its warranty (I just didn't get on my projects like I thought I would and barely used it during its first 3 years...but at least I got it before they further devalued the dollar--yay).

I'm really at a loss as to what operator error might be involved.  Page 26 of the supplemental manual has "Plunging too slow can cause the mortise slots to be tilted slightly."

The slots are not obviously tilted, so does that leave a non-perpendicular plunge as the most likely culprit?  Flexing in the material?

Does anyone have any experience with this problem?  If so, how did you solve it?

Is it jig-building time (so that the Domino's fence has more from which to register)?  Domiplate + Seneca "The Dock" time?

I'm loathe to plunge into the actual materials until I solve this (it was the whole reason I bought the darn thing) and would hate to just go buy a doweler...but this project's time has come and I can't wait too long to figure out what's wrong.

Thanks in advance for any tips.

 

[squall_line]

Is that from multiple mortises or a single mortise on each piece?

If it's from multiple mortises, it's more likely that the fence height is moving on you as you move further down the piece, leading to uneven registration and non-flush faces.

 

[ChuckM]

Did you check the flatness of the boards? Cups in plywood sheets are pretty common.

The sample mating boards seem to be quite long. If some of the boards are slightly cupped and the fence registrations on the boards are not consistent, the mating surfaces might not be flush. Examine the mortises on the boards for clues.

 

[waho6o9]

Have you referenced from the same face?

What's the measurement of the height differences? It looks pretty consistent. 

 

[Festdewalkita]

Is that from multiple mortises or a single mortise on each piece?

If it's from multiple mortises, it's more likely that the fence height is moving on you as you move further down the piece, leading to uneven registration and non-flush faces.

It's from multiple (3 pieces of skinny ply, 4 dominoes--200 mm spacing)...fence was not/is not loose.

 

[Festdewalkita]

Did you check the flatness of the boards? Cups in plywood sheets are pretty common.

The sample mating boards seem to be quite long. If some of the boards are slightly cupped and the fence registrations on the boards are not consistent, the mating surfaces might not be flush. Examine the mortises on the boards for clues.

Man that *would* be some cupping!

There is some variation in the plywood, but it is smaller than the domino's fence.  I guess the question becomes is it cogent at the edges of the fence (considering the 200 mm spacing).

 

[Festdewalkita]

Have you referenced from the same face?

That's one of the 4 rules (#1, I think) that Sedge talks about in his videos.

What's the measurement of the height differences? It looks pretty consistent.

It's not consistent, on either end.  Furthermore, I had the outriggers dialed in (the L one was so bad, to get 200 I set it to 199mm), and the first thing I noticed was lack-of-flush on the end (at least that's consistent).

These are good questions...I think the face's lack-of-flush is due to flexing material, so I'm going to do a Domiplate (ordered last night) and a home-made DominoDock/The Dock (they were out on Seneca's website) and just bring the material to the DF 500 without having to worry about a skinny piece of material overhanging (so it has even less purchase on the workbench).

 

[waho6o9]

Okay
Back to square one. Don't use outriggers just yet. 

You're wise to use scrap pieces.  Lay 2 pieces out, mark them face side up. Make sure both are flat when plunging.

Your results should be stellar. I lift from the back where it plugs in and gently plunge the cut, thanks to FOG for that tip

 

[Crazyraceguy]

In my experience, misaligned parts are always a technique issue of some sort, not the machine itself. The good news is that improving the technique will fix it.
The main thing with any parts that are thinner than 20mm, is that it has to be hanging over the edge of the bench. If the Domino base contacts the table, rather than freely hanging over, it will move the mortice, often crooked/tilted too.

 

[woodferret]

And if you have to hang over the edge with a bendy flexible piece, just make yourself a quick carrier board with something stiff + scrap pieces (as a fence) and some double sided tape.

 

[bertv]

Your images show some burning in the domino holes. Could be the cutter is too dirty or needs replacing.

 

[jeffinsgf]

CRG beat me to it. Anytime I've had similar problems it was from the base of the Domino contacting the workbench.

 

[Packard]

This is all very interesting.

I don’t use a Domino.  I do (rarely, lately) use a biscuit machine (Porter-Cable).

I found that using the fence invites my “user error”. 

Whenever possible, I bank off of a flat surface instead of using the fence. In most cases doing so is fairly easy.

It that not the case with the Domino machine?

 

[Hipplewm]

This is all very interesting.

I don’t use a Domino.  I do (rarely, lately) use a biscuit machine (Porter-Cable).

I found that using the fence invites my “user error”. 

Whenever possible, I bank off of a flat surface instead of using the fence. In most cases doing so is fairly easy.

It that not the case with the Domino machine?

I try and this as much as possible - the base is more stable and muss less prone to error than the fence.  I also use the seneca plate in lieu of the fence if at all possible and use the fence as a last resort - not that is isn't accurate but using most 5/8 and 3/4, you can't do it flat on a workbench and then you are relying solely on the fence and technique etc.

 

[Packard]

A long while ago, I made what is essentially a bookend made from melamine clad particle board.

It is about 8” wide and 10” tall. It was assembled using pocket holes on opposing sides of the board so I could “fine tune” the 90 degree angle.

I can clamp a board to the vertical and cut my slot using the base of my biscuit cutter against the bottom.  If the board has any cupping, it is just over a distance of 8”so nearly unmeasurable.

I have never seen a “Seneca plate” variation for biscuit cutters. 

I moved away from my biscuit cutter because I have an irrational compulsion to make things stronger than they have to be.  And then the next time try to make it stronger yet.

I challenged myself to build a medicine cabinet using butt joints, glue and nails only.  After it was assembled, it seemed way stronger than necessary and would only get more robust when I would factor in that the wall it was attached to would be part of the structure too.

If I got a Domino, the obvious next step would be to make my projects from welded steel. It’s a progression. [big grin] [eek]

 

[woodferret]

This is all very interesting.

I don’t use a Domino.  I do (rarely, lately) use a biscuit machine (Porter-Cable).

I found that using the fence invites my “user error”. 

Whenever possible, I bank off of a flat surface instead of using the fence. In most cases doing so is fairly easy.

It that not the case with the Domino machine?

No - fence is preferred.  I only use the base for the mid-panel jobs.  The base is subject to tilt and all the other concerns about bowing that were brought up in this thread... the fence localizes the cut to that specific region of the stock, minimizing the effect of bows.  I find the ergonomic knob placement on the DF500 fence enough to ensure flatness, unlike the Zeta P2 and other biscuit lineage machines where I have to contort into spider hands to keep it in place.

 

[Crazyraceguy]

This is all very interesting.

I don’t use a Domino.  I do (rarely, lately) use a biscuit machine (Porter-Cable).

I found that using the fence invites my “user error”. 

Whenever possible, I bank off of a flat surface instead of using the fence. In most cases doing so is fairly easy.

It that not the case with the Domino machine?

It is ergonomically the same, so yes, you could and I often do reference the base of the machine. The main difference is that the Domino is a bit thicker in that area. The centerline of the cutter is 10mm above the base plate surface.  With 3/4" sheet goods, this is totally fine, though it is best if you turn your pieces good-side down. You are after all trying to get those faces flush, any difference in materail thickness would show on the bottom. (if there is any)
With thinner material, you need to rig up some kind of spacer, to get the machine in the right location.

 

[ChuckM]

To use the base as the registration face, one condition must be met. Both the bench top on which the boards are placed and the boards must be reasonably flat. When using the fence for registration, the flatness of the bench top is not critical.

I see no advantage (in terms of speed, set up, accuracy, reduction of user errors, and efficiency) of using the base for registration in typical applications except when doing the mid-panel joinery as pointed out by [member=72072]woodferret[/member] or when using certain jigs or dedicated setups such as the Veritas domino table or, as used by some people, the Domino plate for 1/2 or 3/4" stock.

The Domino machine used with its narrow setting is a precision joinery machine unlike the biscuit machine. Don't overthink; the DF is a well-designed machine with potential areas for improvements, but not in using its base for reference in a general, common day-to-day operation.

The Fine Woodworking video that shows how to use the DF like a biscuit joiner tells me they didn't have an in-house domino joiner expert.

If one wants to use the DF like a biscuit joiner, my advice is to save the money and buy a biscuit joiner.

 

[Cheese]

Ya I'm with Chuck... [smile]

I always register off of the fence for doing edge work. That way I need to make sure only 2 surfaces are clean, the top of the board and the bottom of the fence.
If you register off of the base, 4 surfaces need to be cleaned, the bottom of the board, the top of the work bench where the board sits, the top of the work bench where the Domino base sits and the bottom of the Domino base.

Also, the top of the workbench needs to be flat as does the bottom of the board where it rests on the workbench top.

 

[Festdewalkita]

I used a Seneca Ww '"The Dock" for DF500' and a 3/4" slash 1/2" Domiplate with ridiculously fantastic results.

And if you have to hang over the edge with a bendy flexible piece, just make yourself a quick carrier board with something stiff + scrap pieces (as a fence) and some double sided tape.

  I think if one were to consistently use the fence for small parts, that this would be *crucial*.

Your images show some burning in the domino holes. Could be the cutter is too dirty or needs replacing.

That was burn from the saw's cut (operator error, but different operation).

This is all very interesting.

I don’t use a Domino.  I do (rarely, lately) use a biscuit machine (Porter-Cable).

I found that using the fence invites my “user error”. 

Whenever possible, I bank off of a flat surface instead of using the fence. In most cases doing so is fairly easy.

It that not the case with the Domino machine?

I try and this as much as possible - the base is more stable and muss less prone to error than the fence.  I also use the seneca plate in lieu of the fence if at all possible and use the fence as a last resort - not that is isn't accurate but using most 5/8 and 3/4, you can't do it flat on a workbench and then you are relying solely on the fence and technique etc.

This is what I'll be doing from now on.  The fence will be my absolute last choice.  I have a Seneca Ww 0" slash 1/2" Domiplate; a 12mm slash 18mm Domiplate; and a metric shim set inbound.