dowel pins too tight (follow up on Jessem dowel jig)

[Bill Huber]

The hole and the dowel diameters have to be attended to for every session. Dowels should be sized through a steel plate before use and some material should be shaved away to verify the sizing.

I will have to disagree on that point if you are using expandable dowels, they should fit the hole and once in the hole with glue they will expand to the point you can not get them out.

In fact if you put an expandable dowel in a hole with no glue and just let it set there for a while and there is some humidity in the air it will expand to the point it is hard to get out.

If you shave off the outer part of the expandable dowels then there is no place for the glue to come up as you push the dowel into the hole and can form an air lock at the bottom of the hole and you can not get the dowel to set to the bottom.

[Paulh Tremblay]

Can you tell me if I have aligned the Jessem jig correctly?

I make an X on each of the reference pieces. I then make an X on the surfaces that will receive the dowels. I put a check mark on the faces of the pieces.

When I drill the edge, I make sure the face (with the check mark) is flush against the alignment bar. I align the edge of the Jessem jig to the edge of the piece with the X.

When I drill the face, I make sure I drill the surface that does not have the face. I align the Jessem jig to the edge nearest the X.

I made a test box and did not align the alignment bar to the face of my piece when doing he edge drilling; hence the joint was not completely flush.

What surprises me (and the reason I ask about alignment) is that you you don't always use the same bushing when drilling the face as you do with the edge. Lets say you start with the left most bushing when you drill your edge. When you start with the face, you sometimes use the bushing furthest to the right. Only because of the exact precession of the jig do the holes line up. I thought I was doing something wrong, that surely you have to use the same hole when starting each piece, but I just can't see how that is possible. In other words, I might drill from left to right when drilling the edge piece, but then have to drill right to left for the face piece.

[Bill Huber]

Paulh, I am not sure if I understand all you are saying and asking.
Here is a thing I was working on that may help and get us going in the right direction about your questions.
The main thing is you ALWAYS use the same reference face and the same reference edge.

Here are 2 things I have done to the jig.

http://www.sawmillcreek.org/showthre...essem+doweling

http://www.sawmillcreek.org/showthre...essem+doweling

Jessem dowel-1.jpg Jessem dowel-2.jpg Jessem dowel-3.jpg Jessem dowel-4.jpg

Jessem dowel-5.jpg Jessem dowel-6.jpg Jessem dowel-7.jpg

[Paulh Tremblay]

edge1.jpgface1.jpg

The first picture shows me drilling for the edge. I am making a box. You can see the tape that marks the reference edge. I have the guide block against the face of the board.

The second picture shows me drilling the face. You can no longer see the tape. The tape is on the other side of the jig. I cannot possible use the original reference edge for the face joint. The only way I could use the same reference edge is if I flipped the board over and drilled on the wrong side.

[Loren Woirhaye]

The jigs is made to insane tolerances. The offset from the edge is identical for woodworking purposes. The middle hole is dead middle and all the holes are evenly spaced. You can index off either edge and it will be the same. The edge of the inside face of the perpendicular fence part represents the plane of the outside edge of the board, generally.

What you're dealing with is however understandable. It took me awhile to model the way the jig works in my brain.

[Paulh Tremblay]

I concluded the same thing after seeing my edges perfectly aligned. (The faces were not, because I didn't align the face to the reference block, and of course 3/8'' is not exactly one half of a 19mm piece of MDF.) I just wanted to make sure I wasn't doing something wrong.

[Loren Woirhaye]

If you drill wrong, fill with half-dowels and glue and start over. I've done that a few times. Good reason to acquire a flush cut saw.

[Paulh Tremblay]

I just got the 9.7 mm replacement bit from Dowelmax, and it won't fit in the jig. The bit that accompanied the Jessem jig is 3/8'', which explains why the dowel pins fit so tight.

I drilled two holes with each bit (obviously, not using the Jessem jig). I tested several different dowel pins, and got interesting results.

In some cases, the pins fit nicely into the 9.7 mm hole, but would not go into the 3/8'' hole without excessive force. In some cases, the dowel pins fit nicely into the 3/8'' hole, but were too loose for the 9.7 mm hole. Millscraft worked very nice with the 3/8'' bit. Some pins from Woodcraft worked good, but others from the same package were too tight.

I am a bit disconcerted about getting pins to fit, especially since I don't have the option to use a slightly bigger bit.

[Paulh Tremblay]

I just did a test fit with 10 dowels using Jessem's own dowels.

http://www.thetoolstore.ca/viewItem.asp?idProduct=16725

I had to use a clamp to dry fit the pieces because the dowels fit so tight. The joint split in several places.

I had to use pliers to remove the pins, and one pin wouldn't come out without my having to bust it out. I measured the pins with a caliper and noted that they tended to be 1/128 inch larger than 3/8''.

I then tried other dowel pins. The only dowels that fit easily are the ones made in China, dowels that are probably technically undersized.

Next, I used Dowelmax's bit to drill a hole. All pins fit easily in this hole.

I can't fathom why Jessem changed their bushing so the 9.7 mm dowelmax drill bit no longer fits.

[Ole Anderson]

I made my own dowel plate using a chunk of 1/4" steel plate and the same size bit as used to drill the dowel holes and it worked fine. Finger push fit. As stated, just drive the dowel through the steel plate to resize. Just be sure to leave sharp edges in the plate, you want to shave the dowel, not compress it.

But if you want a slightly undersize dowel, get a reamer and enlarge an undersize hole in the plate as much as you want. Here is the catalog I used to use: http://kbctools.com/usa/Navigation/NavPDF.cfm go to page 80 for decimal reamers. Navigate to page on the upper left. To do this correctly, you need a drill press.

[David Winer]

I could have used a mallet to hammer the joint together, but I don't believe you should fit dowel joints together that way. The videos for Jessem and Dowelmax show the joints going together easily with the push of a hand.

Has anyone experience with the dowel pins sold by Jessum? I would expect their pins to match quite well with their own jig. Seems better to me than the various re-sizing schemes discussed in this thread. I haven't yet ordered them but plan to give them a try.

The company describes their pins:

Our pins absorb some of the glue moisture and expand to take up the space left by the shrinking glue, creating an excellent mechanical and chemical bond.

Our Expansible Dowel Pins are milled round and slightly oversize, then grooves are impressed into them creating an accurate, strong, joinery element.

[Bill Huber]

Has anyone experience with the dowel pins sold by Jessum? I would expect their pins to match quite well with their own jig. Seems better to me than the various re-sizing schemes discussed in this thread. I haven't yet ordered them but plan to give them a try.

The company describes their pins:

Our pins absorb some of the glue moisture and expand to take up the space left by the shrinking glue, creating an excellent mechanical and chemical bond.

Our Expansible Dowel Pins are milled round and slightly oversize, then grooves are impressed into them creating an accurate, strong, joinery element.

Jessem, DowelMax and Lee Valley all get their dowels from the same supplier.
Those dowels work great with the 9.7mm guides and bit but are just a little oversize for a 3/8" bit.

[Paulh Tremblay]

I did two tests with these dowels. In the first, I used the dowels out of the bag. The dry fit was so tight I actually had to break a dowel to remove it. I did not even try a glue up.

In the second test I microwaved the dowels for 2 minutes. They fit nicely during the dry fit. When I glued the joint together, I needed 4 clamps for a 16'' piece. I just checked a minute ago and saw the test piece had developed a crack because of the excessive pressure. I may have used too much glue.

[David Winer]

I did two tests with these dowels. In the first, I used the dowels out of the bag. The dry fit was so tight I actually had to break a dowel to remove it. I did not even try a glue up.

In the second test I microwaved the dowels for 2 minutes. They fit nicely during the dry fit. When I glued the joint together, I needed 4 clamps for a 16'' piece. I just checked a minute ago and saw the test piece had developed a crack because of the excessive pressure. I may have used too much glue.

Paulh, from Bill Huber's comment about two sizes of drill bit it seem important to know which size you used. Your results indicate a mismatch in your test. You didn't specify which dowels you used in the test but presumably they were Jessum, right?

What we need to know from someone's experience is: whether the Jessum dowels work without complications in the Jessum jig with what drill bit?

[Paulh Tremblay]

Paulh, from Bill Huber's comment about two sizes of drill bit it seem important to know which size you used. Your results indicate a mismatch in your test. You didn't specify which dowels you used in the test but presumably they were Jessum, right?

What we need to know from someone's experience is: whether the Jessum dowels work without complications in the Jessum jig with what drill bit?

They don't. The dowels I used in both tests were Jessem's dowels. I used the bit supplied by Jessem, the 3/8'' size. A Jessem rep has informed me that there is a flaw in the Jessem Jig design, and suggested I return the jig.