Fence and trap clamps

Kinks and possible issues that lead to frustration

Moderator: Michael

Fence and trap clamps

Postby quiinc » Sat Mar 14, 2009 9:47 am

I assembled my JMP without issues and spent an afternoon with my daughter using it to cut miters for small picture frames. I was stunned by the glass-like surface of the saw cuts. I experimented a bit, using hide glue to make some end grain rub joints. They are quite strong.

Even with the trap clamps, though, we had some trouble holding the pieces for miter cuts. They kept coming loose. We used an additional clamp to hold them tight, and that helped. Late in the day I remembered reading in a review or somewhere that some sandpaper glued to the fence and clamps would make a big difference.

It did.

I don't think this recommendation is in the manual -- if it is, forgive my oversight -- but it made all the difference for holding the workpieces tight.
Posts: 7
Joined: Thu Aug 14, 2008 6:53 pm

Postby John » Sat Mar 14, 2009 12:08 pm

You know, all of my trap clamps on the demo units have 220 grit stuck to the faces--it is a complete oversight on my part to not mention it. We will revise the manual. Thank you for sharing. Of all the cuts the JMP will do, miters need the most forethought regarding clamping and sandpaper really helps.

Congrats on getting your JMP up and running--now you know what all the hullabaloo is about--the cuts are unbelievable. Chris Schwarz took a lot of grief over his statement "Cleanest cuts I have ever seen, hand or powered".
Now maybe he will get some apology emails...

I can't tell you how you made my day today by sharing that you have involved your daughter making frames. Please post a picture of the frame and if you are comfortable, the two of you! Little victories like this are crucial to balance out all the negativity in our society today.

Short story; Recently during a demo at the Crucible in Oakland, a small girl wanted to try the JMP. Unfortunately it was set up for me (6'3") and there was nothing in sight for her to stand upon. Her dad held her up and she made a cut in a small piece of wood and said to her Dad; "Daddy, if you had one of these I could make things without you having to supervise me."

Well, they left and I have no idea if they every called the office. But I do know there were two people watching that did buy JMP's based on that one observation--this tool can involve the whole family if they show interest.

Anyway, thanks for the post--I love getting good tools in peoples hands but this is way better!

Site Admin
Posts: 187
Joined: Thu Apr 10, 2008 11:54 am

Postby User304209 » Wed Mar 18, 2009 5:05 am

Important !!!

Be sure not to place the sandpaper where it would interact with the blade as I noted in my review at ...
under post no. 7 Fixturing, Work Holding Requirements &
The Cutting Experience with Appropriate Applications.

I cut out part of that section and posted it here......


Cutting and work holding

As John remarked "When you make a cut and it's a new species of wood, or a new width or a new thickness or whatever, it's a good idea to find out where you're at." This is done with a light cut to gauge the resistance of the cut. In some woods you can't sense a thing...others you know intuitively that you need to make a pitch adjustment.

In powering/operating the Jointmaker Pro You're pushing with one hand and cranking with the other. Within this rhythm there are three basic ways to approach your cut; one is to make one turn with the crank per stroke cycle with the sliding table. With this technique it is likely you're not engaging all of the teeth and the cut occurs on the back half of the blade - and this works fine. By rotating the crank more than one rev (depending on the pitch/width/species variables) you will engage more teeth and lighten the chip load per tooth. In order to do that you need to determine, through cutting resistance, the optimal pitch for your board - this takes about 15 seconds once you know what you are doing. The third way of sawing is by pushing forward a few inches, back up an inch, push forward twice as far as the first time, back up an inch and work your way down the blade while climbing the blade - all without a full table retraction. This works too but relies on touch to determine when to stop each forward motion and is not as uniform as a full pass stroke.

When holding small stock by hand, the closer your fingers are to the blade (sounds crazy, but in practice it's not) the less vibration and more control over the negative feed of the blade. When cutting extremely small length pieces it is advisable to double-stick tape a false table of aircraft plywood (1/16" thick) to the sliding table (the two tables are most often bridged by the fence and act as a single table), make a through cut and your fall-off will stay on top of the table. This technique is also valuable for knowing exactly where the kerf of the saw is and this kerf can be used as a dead-accurate reference - like cutting marked dovetails on the proper side of the line, this is incredibly accurate and easy. And yes, you can cut your finger if you put it in the way of the blade. Keep in mind; this saw is no more dangerous than any sharp handsaw, in my opinion.

Although the tables can, and do work independently, I found the cuts to be easier when they were bridged with the fence. And in most of the cuts I wanted to test, the tables were bridged. Miter cuts require a rear bridge for the cuts to be perfect.

I found that that you monitor the cutting action by the sounds you hear. When you hear a "rumble" in the blade, the pitch is too aggressive, or there are too many teeth engaged with the stock - wide boards are cut differently than narrow stock. If the falloff portion of the stock is not clamped, you'll hear it. I found that perfect cuts were predictable when the stock was clamped on both sides of the blade. Remember, when sawing by hand your stock is either clamped or held in a vise, with the Jointmaker Pro your vise/clamp is the table and you need to know that accurate work can only be achieved if your stock is rigidly held. It's like any hand saw operation, let the saw do the work - if possible I recommend always clamping your stock with the exception of really small cross-sections. Determining how to pitch the blade and table technique is part of the "getting acquainted period" I continue to mention.

If not clamped tight enough, the work will slip and you could damage your blade. If you don't want a small burr on the falloff piece, it's wise to clamp both sides. Having 180 grit sandpaper on the face of the fence (with double faced tape) really helps the holding power and combats slippage; just make sure not to place it where you would trash your saw sharpness.

In summary, when the pitch is correct, the stock firmly clamped, this tool sings. And it is easy to tell, it simply sounds efficient.
Posts: 9
Joined: Wed May 14, 2008 10:19 pm

Return to Jointmaker Pro Known Issues (Complaint Department)

Who is online

Users browsing this forum: No registered users and 2 guests