Problem getting flush butt joint with DF500

[mazdaq100]

First thing to say is I'm a bit of a novice and just wanted some thoughts on where I'm going wrong. Had the DF500 for about a year and the first project I did with it was a large bookcase, which went really well - all butt joints were lovely and flush. Absolutely delighted with the final outcome.

Since then, I hadn't used it for a while but came back to it recently to build a few more small media units for TV/AV equipment etc. I've done 3 of them now, and on each one I'm having trouble getting a flush butt joint on some of the corners. I'm getting anywhere from 0.5mm-1.5mm out on the join - I've attached a couple of photos that should show what I mean. I know the middle of the mortice should be 10mm up from the bottom/edge of the board but I'm getting anywhere between 9mm-10.5mm at times.

So where am I going wrong? I'm sure the tool is set up correctly. I take my time on these mortices as I know if you go too quick, you can get tear out etc. I make sure I've set the right width, depth etc on each one until I get more practice at it.

I'm working on a flat level surface. The only thing I can think is that a bit of sawdust has got under the workpiece or the bed of the DF500, raising either of them up by a mm or so to create this indiscretion. Thoughts?

 

[Tom the Remodeler]

Best practice for using the Domino (and other similar tools) is to reference off the fence, rather than referencing the table surface, for all of the contamination reasons you already listed. So, set your flip-down fence to the appropriate setting, and make sure you're referencing the correct face of each piece. Even if the fence is "off" somehow, so long as you're referencing from the same faces they should properly align.

 

[mazdaq100]

Thanks Tom. That makes sense, will use the fence to reference in the future rather than the table.. Had a read of another thread too, which helped.

 

[Crazyraceguy]

It's all about reference edges and keeping them "straight".
Don't necessarily shy away from using the base of the unit as a reference. It is very solid and absolutely cannot move from the center of the bit.
Where many people get into trouble is with 3/4" material. When you are cutting into the edge, that edge must be hanging over the edge to the table. If not, the base of the tool will be affected by it.

 

[mazdaq100]

Yes I was using 3/4" or 18mm in the UK. So, I had set the fence height to 16mm but did not have the edge overhanging the table edge. So the base of the tool must have come off the table slightly, setting everything off.

I realise now that if the edge was overhanging the table edge, then I wouldn't have this issue. Presumably still have the fence height set to 16mm? Obviously there's no 18mm height option. It's either 16mm or 20mm. I guess the most important thing is referencing off the correct faces for each piece.

 

[bobtskutter]

Reference edge is important (I've made lots of mistakes getting my inside / outside mixed up)
If you're referencing the machine off your work bench you need to make sure the board is flat on the workbench.  Like you said saw dust can get in the way and the board might not be flat.  It's also possible to tip the machine a little since you're trying to hold the board, hold the fence and plunge the machine (3 hands).
If you use the fence as the reference you hold the handle on the top of the fence and that helps stabilise the machine.
Use the Festool base bracket thing to help make plunges into the face of boards whilst using the edge + fence as the reference, or get a TSO BigFoot.
There are a lot of SedgeTool videos about using the Domino, they're very good.

Regards
Bob

 

[cpw]

I often prefer the base for reference rather than the fence.  Especially if the domino is not a straight up butt joint it is nice to be able to clamp a straight edge to your workpiece and then reference off that.  For 3/4" material, I like to have the base on my MFT with the workpiece butted up against a stop.  That way I can reference off the base and bottom of the material without actually having to clamp the piece, the pressure of the domino plunging is enough to keep everything in line.

Depending on how the workpiece is situated you might want to use the fence on one side and the base on the opposite side.  The base is exactly 10mm; and there is a stop for the fence at 20mm - which is really 10mm on the DF500 - so you can easily mix and match.

The most important thing is to make sure you use the same reference edges on both sides of the joint so that things are not slightly offset.  With 3/4" material it can be easy to get "turned around".

 

[mazdaq100]

Thanks guys. Made some amendments this morning and now have some lovely flush butt joints. Most importantly, it's now clear in my head where I went wrong and best practice for next time.

Appreciate the help guys.

 

[jeffinsgf]

Remember, too,there is more than one way to set the fence. You don't have to use on of the pre-set stops. If you want the center of the mortise at the center of 18mm ply, just set the scale pointer to 9mm and ignore the pre-set stops.

 

[Packard]

I had a similar problem with my Porter Cable biscuit cutter.  I ascribed it to operator error.

It is much easier to bank off the base, than the fence.  And with a little thought, it can be done in most cases. Though when cutting surface slots on large sheets of flat goods, it can be challenging. 

I’ve moved to using dowels more often than biscuits so it does not come up so often anymore.  But try referencing off the base plate instead of the fence.

This Fine Woodworking Video is devoted to using the base plate for a reference with a biscuit joiner.  I think most of the video translates well to the Domino machine.  I think it is worth watching, especially if you have an old biscuit joiner sitting around feeling lonely.  [big grin] [big grin]

 

[Packard]

Since I made the above post, I have been thinking about why I stopped using the biscuit cutter.  Every project I made with it turned out fine and was more than strong enough for the task (cabinets).

It was faster and easier to execute than dowels.

Now I am going to have to re-consider it. 

I would note that in my basement shop which is fairly damp, biscuits (and dowels) are best stored in air-tight containers (something more air-tight than a sandwich bag).  Otherwise they tend to swell. 

I buy snacks at BJ’s Club (mostly peanut-filled pretzel nuggets).  The large plastic jars are perfect for that purpose. 

In any case, I am going to rethink the biscuits.  There may be a place for them in the future.  The Porter-Cable machine is nice.

 

[Crazyraceguy]

Since I made the above post, I have been thinking about why I stopped using the biscuit cutter.  Every project I made with it turned out fine and was more than strong enough for the task (cabinets).

It was faster and easier to execute than dowels.

Now I am going to have to re-consider it. 

I would note that in my basement shop which is fairly damp, biscuits (and dowels) are best stored in air-tight containers (something more air-tight than a sandwich bag).  Otherwise they tend to swell. 

I buy snacks at BJ’s Club (mostly peanut-filled pretzel nuggets).  The large plastic jars are perfect for that purpose. 

In any case, I am going to rethink the biscuits.  There may be a place for them in the future.  The Porter-Cable machine is nice.

Just in case you don't know, those swollen biscuits can be "fixed/shrunk" be buzzing them in a microwave oven for a few seconds. Sounds crazy, but it does work. After learning about this problem, I have always taken more care to keep them in an air tight container. Dominos too. My 5mm and 6mm are in ziplock bags, with a desiccant cartridge.

 

[Michael Kellough]

Since I made the above post, I have been thinking about why I stopped using the biscuit cutter.  Every project I made with it turned out fine and was more than strong enough for the task (cabinets).

It was faster and easier to execute than dowels.

Now I am going to have to re-consider it. 

I would note that in my basement shop which is fairly damp, biscuits (and dowels) are best stored in air-tight containers (something more air-tight than a sandwich bag).  Otherwise they tend to swell. 

I buy snacks at BJ’s Club (mostly peanut-filled pretzel nuggets).  The large plastic jars are perfect for that purpose. 

In any case, I am going to rethink the biscuits.  There may be a place for them in the future.  The Porter-Cable machine is nice.

This the same basement that is mostly above ground?

My problem with biscuits is that they’re always too loose to depend on for surface registration.
I was so happy when the Domino arrived.

 

[Crazyraceguy]

My problem with biscuits is that they’re always too loose to depend on for surface registration.
I was so happy when the Domino arrived.

They aren't long enough either. (as far as how deep they go into the material) I had a DeWalt biscuit jointer, years ago (before the shop fire) essentially because it was the only real alternative to dowels.
Nothing wrong with dowels, but until fairly recently, the commercially available jigs weren't so great.
They were ok over short distances, but the more you needed to get aligned at once, the better biscuits seemed to look.
The DF500 solved all of the at once....plus offering multiple sizes.
Biscuits are worthless in face frames, Dominos really shine there. You really can't attach table legs with biscuits, Dominos do it very well.
I never saw the need to replace that biscuit jointer.

 

[Packard]

Since I made the above post, I have been thinking about why I stopped using the biscuit cutter.  Every project I made with it turned out fine and was more than strong enough for the task (cabinets).

It was faster and easier to execute than dowels.

Now I am going to have to re-consider it. 

I would note that in my basement shop which is fairly damp, biscuits (and dowels) are best stored in air-tight containers (something more air-tight than a sandwich bag).  Otherwise they tend to swell. 

I buy snacks at BJ’s Club (mostly peanut-filled pretzel nuggets).  The large plastic jars are perfect for that purpose. 

In any case, I am going to rethink the biscuits.  There may be a place for them in the future.  The Porter-Cable machine is nice.

This the same basement that is mostly above ground?

My problem with biscuits is that they’re always too loose to depend on for surface registration.
I was so happy when the Domino arrived.

The registration occurs when the biscuits swell from the moisture.  The problem occurs when you glue both the biscuits and the joint (which I always do, but which the video I posted does not).  The glue on the joint sets faster than the biscuits swell and that means that the joint might not register. 

 

[smorgasbord]

The registration occurs when the biscuits swell from the moisture.  The problem occurs when you glue both the biscuits and the joint (which I always do, but which the video I posted does not).  The glue on the joint sets faster than the biscuits swell and that means that the joint might not register.

I've always wondered if low-quality biscuit joiners have more runout which might make the slot wider than nominal, leading to a loose fit.

As for glue setting, wouldn't that depend on the type of glue being used? If Titebond III, for instance, there's a longer set time. Although I could see where the initial tack from the glued long-grain contact holds well enough to resist any swelling from the biscuits that might try to align the joint better.

Interesting.

I've also wondered why companies like Seneca can do well making what are essentially aluminum plates that attach to the base of the Domino. My conclusion has been that for production-ish work having a Domino set to the right thickness with no possibility for error nor misalignment is worth it to those shops. Then again, maybe that I'm using a DF700 which might have a better fence than the DF500 is also a factor in me not ever thinking I needed one of those offset plates.

The base-hitting-the-table thing when using the fence is indeed a long-time biscuit joiner issue that I could see replicating itself with the Domino.

 

[Packard]

If they are after the high production user, the Seneca devices will have a steep uphill climb.

There are fully automatic dowel machines that will drill, glue and install the dowels.  Plus various degrees of automation for clamping.

A number of years ago, I did some Internet research on fastening, and which ones were strongest.  Most of the testing shown was for one sample.  One assembled sample is not going to give definitive results.

However, there were two tests done, one by the kitchen cabinet trade association (I don’t recall the exact name of the association), and another by the ready to assemble furniture association. 

They have similar, but not identical assembly requirements.  Mainly the kitchen cabinets rely on the wall for much of the racking strength (side to side wobble).  The ready to assemble (RTA) need racking strength independent of any wall attachment.

But they got nearly identical results.

The test was to have a (1) vertical panel and a shelf hanging by fasteners to the panel.  They added weight to the end of the shelf (which was about 12” long) and watched to see  how much weight the shelf could carry. 

All tests were done with no glue.

The worst, was the dado (which was my preferred method).  It failed at a poundage less than the meter could read.

The 1/4 turn cam assembly provided the next weakest joint.

Drywall screws were next.

Dowels and Confirmats were at the very top of the strength.  As a rule the dowels won; they are vastly cheaper than Confirmats and they benefited from automation.

The drywall screws provided good pull strength but were brittle.  They offered little racking strength.

The Confirmats offered good pull strength (eliminates the need for clamps for some gluing operations) and good racking strength.

I tried finding the studies again a couple of years ago, but Google failed me.  I’m sure they are still out there, I just could not find them.

The RTA test appeared to be largely a IKEA test.  IKEA has since developed a special wood dowel system.

I moved from dado construction (which always served me well) to dowels after reading the tests.

Both the tests were run by independent testing services and several samples of each were tested (unlike most of the tests online where they only test one).

Dominoes were not tested because they felt the system did not lend itself to high production settings. Building 200 base cabinets a day, for example.

Lately, I have been trying to match the joinery the the job.  So I am using pocket hole screws for face frames—none of the other systems seem to make as much sense.

I am using dowels for cabinet boxes, but dados for cabinet backs. 

Interestingly, both tests (different labs) came up with one identical observation:  No fasteners within 2” of the end of a panel.  Apparently, you need that much panel to the side of the fastener to prevent the panel from splitting.  So whether dowels, Confirmats, screws, etc., I make sure they are not within 2” of the end of a panel. 

Sorry for running on so long.  I have no doubt that the dominoes would have fared well in the tests if they were included.  It just did not meet their production requirements.

 

[Crazyraceguy]

As far as speed, there really isn't anything faster than a machine like this.
You scan a bar code, place the part against the fence and step on the pedal.
It drills, squirts water into the hole and jambs the dowel in, essentially faster than you can see it happening. The dowels have a glue coating, which is activated by the water.
The machine we had before this upgrade squirted glue, but that takes quite a bit more maintenance.
Cleaning, clogging, etc.
With a lot of parts having the same spacing/pattern, you don't even have to scan every part. It goes very quickly, parts are sorted/stacked, coming from the CNC, and they run in batches.

 

[Packard]

That type of dowel machine, and the semi-automatic clamping machines were the reason that Dominoes were left out of the studies I read. Additionally, dowels are dirt cheap compared to dominoes.

I frequently take a fluted dowel, rest it on my work table, and then take a fine tooth metal working file and roll the dowel down in diameter.  It can make assembly much easier.  It flattens the peaks and does not remove any material.

Fluted dowel (to avoid confusion):

The flutes are not cut into the dowel, they are rolled and compressed into the stock.  Initially, I was concerned that the rolling operation would compromise the joint.  But I experimented with those rolled (modified) dowels by painting them with water and assembling the joint.  Left overnight the joint seemed nearly as strong as if I had used glue.  The dowels swelled so tight that I had to hammer the joint open.

This is another reason for buying dowel pins already formed instead of cutting your own.  If you cut dowels from rod, they will not swell nearly as much, won’t have the chamfer for easy insertion and will not hold as much glue.  From the right sources, they are going to be cheaper than making your own.

 

[Packard]

I tried another search for those tests I referenced.

I came across this one, which turns out to be far more scholarly than my attention span.  I also cannot figure our why the National Library of Medicine would be publishing this type of work.

If you have the attention span to figure this out, post your opinion.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8658495/

My Google search was:  ready to assemble furniture fastener research

Which I have linked here: https://www.google.com/search?q=rea...search&ie=utf-8&oe=utf-8&client=firefox-b-1-m

Later on, I will re-visit the google search and see what I can learn.