Miller Dowel System

[Mike Holbrook]

I am ordering parts for a project I am working on, a German Work Box (rolling tool cabinet). The plan uses Miller Dowels to hold butt joints, 3/4" plywood, together. I have never used these dowels but like the idea of using wood instead of metal fasteners and though it would be a good chance to try them out. I know Lee Valley, Highland Woodworking and several other well respected woodworking suppliers have carried them for quite a while. I mentioned them in a post about drawboring trying to draw out some comments on them, but did not find anyone using them for that job. I am trying to get the rest of my parts, all of which Lee Valley has, ordered during the free shipping period.

Apparently the basic set comes with Birch pegs and the drill bit. The pegs come in three different sizes and four different woods. I was thinking about trying out the oak pegs. I am hoping some fellow posters have used them and can offer some sage advise on how well they work and which sizes and woods might be preferable.

[Jim Koepke]

My question would be why not just use regular dowels?

An auger bit and hardwood dowels cut from stock available from lots of sources has always worked fine for me.

jtk

[Ralph Boumenot]

I use all 3 sizes - mostly the smallest and middle sized ones. I make a lot of stools and use them on the braces and the dado joints. I used the big ones on some saw horses i made a couple of years ago - stock was a bit warped and clamped the joints and put in the dowels. The dowels are still holding it true. I made a bookcase and used the dowels to reinforce the dado joints the shelves are held in. No sagging and dadoes are still tight after a year +.
The only problem I have with them is not drilling to deep. I like to leave them a little proud and chisel them flush.
I mostly use the birch ones although I have some oak ones that I use on oak projects.

[Mike Holbrook]

Jim my concern about regular dowels is I have seen a fair number of old joints made with them that have splits from the dowels. It seems to me that there is a sizing issue with regular dowels, too loose and the joint may be weak, too tight and there is the risk of splits occurring. I am wondering if a tapered stepped dowel with horizontal grooves and a special bit to drill a tapered hole has some advantages. The main advantage in my mind is the dowel does not start making pressure against the sides of the hole until it is entirely seated. As I understand it one can tap Miller Dowels in as tight or loose as might be appropriate for the species of wood, the thickness of the wood and the tendency of that particular wood to split. A good tight regular dowel starts pressuring the hole it is driven into immediately and for the length of the hole which I am speculating increases the chance of a split. The gaps built into the sides of the Miller Dowels might further reduce the chance of splitting and increase strength, due to pooling glue in the places the peg does not touch the holes sides.

I just bought a Lee Valley dowel making kit so I am going to try making my own dowels. I am just wondering if the more precise machining of the tapered Miller Dowels might have some advantages I might not be able to duplicate with hand made dowels, so i am thinking about trying some. If the tapered holes & dowels seem to work better I might just make tapered dowels to fit the holes made by the tapered bit.

Ralph thanks for the positive report. I think I will try a bag or two of the two smaller sizes to test them out. I might even try a bag of the larger ones for the saw bench project I am about to do.

[Harlan Barnhart]

I thought the advantage of miller dowels is that glue does not wipe off the full length during installation.

[Don Shirey]

I recently had a problem with a project that necessitated using a butt joint. I made a trial joint of 6/4 cherry and 4/4 oak the oak was end grain. I rabbited the cherry 1/4 inch and using 2 medium walnut miller dowels glued and clamped it together. The boards were 10 inches wide. I waited 2 days and clamped the trial in the vise and tried to pry it apart. Nothing happened, I then commenced beating on it with a substantial mallet. to make a long story, short. I broke the 4/4 oak and the joint never failed. I used the technique in the project and it worked out very well.

[Jim Belair]

I am wondering if a tapered stepped dowel with horizontal grooves and a special bit to drill a tapered hole has some advantages.

Are they tapered AND stepped or just stepped? If just stepped they might have the same tendency to split the stock as a regular dowel in an equally tight hole. And I think they'd only be as secure as a straight dowel if driven home, i.e., to the full depth of the steps. (no experience with them, just speculation)

They seem longer than I would typically use with a straight dowel. The small are 2 5/8" overall length for up to 1" stock. I'd probably use 2" straight.

All this said there is the advantage of not wiping off a considerable amount of the glue so I might just give them a try.

[Mike Holbrook]

Right Harlan, which is what I was attempting to explain with my description of the stepped sides and horizontal grooves causing the glue to collect in the areas where the peg does not touch the holes walls. My minor experience with dowels and biscuits has demonstrated that a tight fit often removes so much glue that the bond is ineffective . The vertical grooves placed in some dowels seem to get compressed away when a straight sided dowel is driven into a tight, straight hole. The horizontally stepped sides and horizontal grooves in Miller Dowels do seem a logical alternative that at least in theory should provide a better glue joint.

Don thanks for the real life example of a successful use of these dowels. Although I will be gluing 3/4" plywood, I think the edge grain in the plywood should bond at least as well as solid hard wood end grain.

Jim, Miller dowels are tapered, stepped along the taper and there are horizontal grooves between the steps. Picture a tapered, stepped ring shank nail. Anyone who has had to remove ring shank nails will appreciate the potential holding power of horizontal grooves covered in heat activated glue.

[Bob Turkovich]

Mike,

I built a blanket chest made of cherry/cedar plywood laminate (made by gluing 1/2" cherry to 1/4" cedar -resulting in a 0.635" thick laminate - I know, not the smartest thing, but it worked). The front/back panels were 46" x 15" and the sides were 18" x 15". To join the corners, I planed 4 15" pieces of cherry down to 0.635" x 0.635". I used 6 Miller dowels to secure the corners to the larger panels and 5 to secure the corners to the shorter panels.

The chest has an upholstered pad on the top and is occasionally used for seating (can hold 2 people at a time) and has held over 250# without a problem.

My son has asked that I use the same construction for a toy chest I'm building for my grandson as the dowels provide a nice aesthetic detail.

[Hilton Ralphs]

Jim, Miller dowels are tapered, stepped along the taper and there are horizontal grooves between the steps.

Are you sure about this Mike?

I found this on their website;

Miller Dowel Company’s TruFit Drill Bits are stepped (not tapered) to create the perfect pilot hole to match a corresponding Miller Dowel

This would imply that the dowels are also not tapered.

Anyway, looks like a decent system.

[Jim Koepke]

Jim my concern about regular dowels is I have seen a fair number of old joints made with them that have splits from the dowels. It seems to me that there is a sizing issue with regular dowels, too loose and the joint may be weak, too tight and there is the risk of splits occurring.

I haven't had a dowel joint split in a long time. One of my dowel tools is a short piece of scrap with a trough cut into it. (This is usually done by boring a hole in a piece lengthwise and then ripping it through the center.) A wood screw with a sharpened point is driven through the piece to exit at the bottom of the trough. A long piece of dowel can be pulled through this to scar the sides. A couple of these scratches allows an escape for excess glue. My guess is excess glue with no way to escape has caused more splits in dowel joinery than a tight dowel.

Found a picture:

Dowel Tool.jpg

This is my old one. It is about 3" long. This one is mostly used for 3/8" dowel stock. Bigger dowels would need to have a bigger trough. It is also used like a dowel cutting miter box.

My accumulation of bits tends to have quite a few in the sizes of dowels. They have a range of variance. When I am going to do some doweling the dowel is measured and then a bit that is a hair bigger is selected to do the boring. Most of the time though that may be a bit of overkill since close seems to be good enough.

jtk

[Mike Holbrook]

Hilton I did not find that exact text on the site, regardless I think the point is the bit and dowels have "steps" and groves with a horizontal orientation that may trap glue better and provide some other benefits too. I understand why the manufacturer wants to make the point that their bits make a different hole than the same old tapered hole tapered screw bits make. The dowels and the bit are larger at the top and narrower at the bottom, which I was referring to as taper. I can see how someone might refer to the dowels as stepped not tapered. I don't know how it would be possible to create a true "stepped" hole with a spiral bit though. How could continuous spirals make a 90 degree angle? I apologize if I led anyone astray in my attempt to describe these dowels that was not my intent.

I got the answer I was looking for, apparently those who have tried these dowels have found them helpful. There are pictures of these Dowels on the Lee Valley and Miller Dowel Company site for anyone interested in further investigating their design. I think pictures make the design clearer than our words can.

[Jim Koepke]

The dowels and the bit are larger at the top and narrower at the bottom, which I was referring to as taper. I can see how someone might refer to the dowels as stepped not tapered.

An honest use of different nomenclatures. Doubt any damage has occurred for it.

The real test might be in what happens inside the joint after the glue sets. Do the dowels swell to make the grooves hang on to the edges of the hole?

It could be the taper/steps causes a better flow of glue in the hole causing a better bond.

Gee Mike, your up late and I'm the one who is sleepy.

jtk

[Mike Holbrook]

Yes, I am Jim ;-) I am suppose to be removing anything I need off an older computer so some consultants can wipe it and load a CRM package on it tomorrow. I am having trouble moving some things that I'm not sure I need anyway so yes I am procrastinating. Plus I have two bitches in heat in crates in a room with two males and they want stop discussing their differences.

Thanks for the tips on making a better dowel above. I have sheet goods spread out on the floor in the hopes of getting started sawing up the 3/4" plywood for a couple wood projects tomorrow while the consultants load software and set up a backup system. One of the projects needs parts I have in my basket at LV, including, you guessed it, Miller Dowels. I am very interested in using wood "fasteners" but I have been afraid they just do not make solid joints. Apparently my fears may have been misplaced.

I think I found the text Hilton mentions above. It appears to be paraphrased from several sentences about Miller Dowel Co.s drill bits and I think he added the "(not tapered)" part, so maybe we old guys should not be posting late at night after our bed times ;-)

[Hilton Ralphs]

I think I found the text Hilton mentions above. It appears to be paraphrased from several sentences about Miller Dowel Co.s drill bits and I think he added the "(not tapered)" part

Nah, my quoted text was copied verbatim from their website. Tapered or stepped or tepped, it makes no difference as I think you will make this work for you.