(05-17-2018, 07:33 PM)Teak Wrote: When it comes to Dowels, nothing beats Dowelmax. One of the best jigs I have ever bought. Check it out at https://www.dowelmax.com/
Just curious Teak - the Dowelmax looks impressive - I own a number of dowelling jigs from the simple Rockler offerings, to the self-centering ones, and to the impressive JessEm shown below - found some registering issues w/ the latter which prompted my purchase of the Joint Genie (yet to use but soon!) - SO, my question to you is whether you've personally tested the Dowelmax to some of the other 'better' dowelling systems? Dave
(05-17-2018, 09:16 PM)giradman Wrote: Just curious Teak - the Dowelmax looks impressive - I own a number of dowelling jigs from the simple Rockler offerings, to the self-centering ones, and to the impressive JessEm shown below - found some registering issues w/ the latter which prompted my purchase of the Joint Genie (yet to use but soon!) - SO, my question to you is whether you've personally tested the Dowelmax to some of the other 'better' dowelling systems? Dave
I am a happy and satisfied user of Dowelmax for almost 10 years. Bought it from the owner / inventor / developer, Jim Lindsay, himself at the Edmonton Wood Show back in the day when they used to have those (god time flies!). I have since then used it for various projects and not once had an alignment or registration issue. It is a beautifully crafted high precision jig, something that I will pass down to my kids.
Before that I had a tried a Milescraft doweling jig that was promptly returned to Home Depot after one use because the dowels would not align! I also have the Veritas Dowelling Jig http://www.leevalley.com/en/wood/page.as...2311,42319 however, never use it because the Dowelmax is so much easier to use.
There are others Dowelmax users here too and I am sure they will chime in too. HTH.
I plan on using the Joint Genie for cabinet work. It promises to be much faster than any of the other systems I've seen. I've only used the self-centering jig + centers in the past for cabinet work and that was very tedious. The Joint Genie looks to be much faster.
No animals were injured or killed in the production of this post.
I took out a cabinet in our kitchen, and am salvaging some of the wood to make a cover for the hole that it left. The face frame was doweled together, and I tried to get it apart by racking it. Didn't work, I'm going to have to cut it.
An apology. I ended up typing a lot more than I intended and more than most will read.
The bad rep dowels got (compared to tenons) is that they were comparing different amounts of surface areas in the joints. A 3" x 2" x 1/2" tenon has 14 square inches of face grain glue area.
A half inch diameter dowel 2" deep has 3.15 square inches of surface. About half of it is against end grain. So to equal the same 14 square inches we would need a minimum of 4.44 dowels, but to get the same amount of square inches of face grain we would need 8 or 9 dowels.
On the other hand the trade associations for the flat pack furniture industry (think "Ikea") and the European cabinet making industry both hired independent research labs to compare the strength of fasteners on sheet goods (18mm --about 3/4").
Dowels came out on top. Followed by Confirmat screws (which act as screws and metal dowels). Followed by regular screws (but far behind the Confirmats). Followed by cam action fasteners. And surprising to me, at the very bottom of the heap was dado joints.
The flat pack (RTA) assembly did not include glue; the cabinet industry work did include glue. They pretty much agreed on all points. Most notably that in all cases there should be no fasteners closer than 2" from the ends of the panels. Those fasteners are greatly compromised.
For me, the dowels aid in alignment and will give good strength to the cabinets.
I researched various high end cabinet manufacturers and among those that use 3/4" plywood dowels on 5" centers seems to be the norm. On low end cabinets (melamine over particle board) the spacing was much closer--about 2½" on center. That being needed because of the greatly reduced strength of the particle board.
Unlike furniture manufacturing, the most worrisome strength issue for the cabinet industry is racking. That is the side to side movement of the top of the cabinet compared to the bottom of the cabinet. Once attached to the wall, it is not so troublesome, but until that point it is an area of concern. For the furniture industry it is an even greater area of concern because the furniture is not attached to the wall.
No animals were injured or killed in the production of this post.
I used the Joint Genie this afternoon and here are some observations.
I made a storage box about 17” deep by 15” x 18” from 3/4” plywood.
1st mistake. I should have watched the video two or three times just before starting. (I had watched it two weeks earlier). It suddenly seemed like I had dyslexia. Was I registering from the correct side of the plywood? From the the correct end of the piece? I did get it right, but I had to do quite a bit of studying before each set of holes.
An attaboy for me. I bought an extra 3/8” drill and drill stop. So I did not have to re-set the depth each time I started on a new joint.
2nd mistake. I drilled for too many dowels. I had 7 dowels for each joint. The dry fit went well, but removing the dowels before glueup was a chore. And while I could get a good fit with just a rubber mallet on the dry fit, the glue created so much hydraulic resistance that I needed three clamps per side on that tiny cube. I should have kept the dowels in a dryer environment. They absorbed moisture and made the fit too tight.
An attaboy for me. The alignment of the joints was perfect. The jig will allow very accurate drilling.
Recommendations to myself.
Store dowels in a dry environment and not in the basement.
Place dowels 4” or 5” on center and not 1-1/4” or 2” on center as I did here.
Watch the video 2 or 3 times immediately prior to the next use.
Observation.
The cube was extremely rigid even before applying the bottom or using glue. When I used dadoes and glue it was only once the glue set that a cabinet carcass would feel solid, and not really solid until I added the back. If this were a cabinet I would say it was much stronger to start. It was also almost perfectly square—out about 1/16” on the diagonal (which I corrected in the glue up phase.
In the morning I will add the bottom.
My guess is that once I have several carcasses under my belt my “dyslexia” will go away and the speed will increase exponentially.
No animals were injured or killed in the production of this post.
The Hoadley article cited earlier is worth reading, as it explains exactly what happens over time. As solid wood moves seasonally, the hole or the dowel distort from a perfect circle to an oval. When that happens the connection between the dowel and hole is reduced to a couple of points and the joint fails. Not that big a deal in particle board cabinets that aren't intended to have a long life span, but if you're using dowels in furniture your work won't last.
The subtitle to the original article is "Why round tenons fall out of round holes . . .". If you look at lots of antiques you'll see this; the pieces falling apart are almost always held together with dowels, while mortise and tenon joints can stay together for centuries.
(05-21-2018, 09:25 AM)Bob Lang Wrote: The Hoadley article cited earlier is worth reading, as it explains exactly what happens over time. As solid wood moves seasonally, the hole or the dowel distort from a perfect circle to an oval. When that happens the connection between the dowel and hole is reduced to a couple of points and the joint fails. Not that big a deal in particle board cabinets that aren't intended to have a long life span, but if you're using dowels in furniture your work won't last.
The subtitle to the original article is "Why round tenons fall out of round holes . . .". If you look at lots of antiques you'll see this; the pieces falling apart are almost always held together with dowels, while mortise and tenon joints can stay together for centuries.
I'd file that article under "don't believe everything you read."
For example, think about the differential we'd see in expansion/contraction over a 3/8" (the size of a typical dowel) distance.
We've got to be talking tenths (ten-thousands of an inch), if that.
(05-21-2018, 11:30 AM)Phil Thien Wrote: I'd file that article under "don't believe everything you read."
For example, think about the differential we'd see in expansion/contraction over a 3/8" (the size of a typical dowel) distance.
We've got to be talking tenths (ten-thousands of an inch), if that.
Just for grins, I used the shrinkulator to identify the difference.
My species of choice was walnut. I used a 24" wide piece, to simulate what I get (actually, a bit more) in seasonal movement in a glue-up table-top I have.
I went with 5% and 9% humidity and the shrinkulator indicates I should see 23.8 (radial) and 23.72 (tangential) shrinkage from summer to winter. While that is a little more than I actually see, it is a fine start.
So 23.8 - 23.72 = .08" difference, over 24".
So .08/24 = .0033" per inch.
So (.0033/8) * 3 or .0012" for a 3/8" dowel.
So worst-case scenario, it would appear the differential between the hole and the dowel could be a maximum of .0024" if the dowels are aligned exactly opposite of what you'd hope. I see that as a 50-50 chance, so I'm going to say that for all intents and purposes, we're back to .0012" (because half the time the dowels would be closer to perfectly aligned).
A few years ago I replaced an old entry door for my garage. Post WWII era, it was cope/stick reinforced with 1/2" dowels. The panels were bad, the framing was no longer square, so I removed this was and tested it to destruction.
Those dowels joints gave me a run for my money, I'll tell ya. I was never able to get separation, just destroyed the joints trying to get them apart.
Dowels are plenty strong, now and into the future.
If you find substantially out-of-round dowels in old pieces, they probably started-out life out-of-round to begin with.
For me the dowels are all about case goods. The independent lab reports and the fact that the both the premium cabinet companies and the high production (read “melamine” sheet goods) manufacturers use the dowels sold me on them.
The first “case” I made using dowels was substantially more rigid in the test fitting (no glue) than any of the dado constructed cabs I’ve made in the past. The dowels add racking strength that screws and dado construction cannot match. Confirmats come in a reasonable second place.
I build mostly cabinets and cabinets masquerading as furniture, so the dowels make a lot of sense for me. I will leave the dowel vs tenon argument to others. But for me, on case goods the dowels are a clear winner.
The construction plan is to dowel, clamp, add a couple of confirmats, remove clamps, move on to the next box.
No animals were injured or killed in the production of this post.
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