|Project by Kelly||posted 11-15-2015 07:09 AM||7127 views||32 times favorited||21 comments|
Log Cutting Jig Using a Harbor Freight or Pony Bar Clamp
A friend bought a riser block for my band saw. Too, I acquired some logs sections that would allow me to take advantage of the increased capability of the saw. The sled I built a few years back wouldn’t handle the wood, so I needed to build a new log cutting sled.
I was in a hurry, and I didn’t want to consume a lot of materials merely because I built in haste. On a whim, I decided to see if I could just use a bar clamp to clamp a fence directly to the log, to give it a flat surface to run on the table and against the fence.
To build the prototype jig, I grabbed a piece of scrap 3/4 ply (okay, it was that 23/32 crap they’re pushing on us now days) and cut it into a couple pieces about four inches wide. Both pieces were a little over a couple feet long. Just a little longer than the clamp I needed for the logs I was going to work.
My intention was to secure the clamp to the pieces of plywood. To do this, I cut some notches in the one I was going to lay the clamp on, so the bar could rest flat on the edge of the plywood and the clamping portions could sit in to it. As well, a longer notch allowed the sliding part to still move.
After notching the plywood, I drilled a couple holes in the clamp, for the screws that would screw it to the plywood.
A second piece, which would laminate to the first, made the jig wide enough the clamp would not contact the fence and prohibit the jig from pressing flat against it.
I cut notches in the second piece of plywood also, to allow the back of the clamping portion of the clamp to set into the wood, and to let the sliding part move back and forth.
The jig has worked so well, I’m waiting for another, longer piece of scrap plywood so I can make a longer version for logs up three or four feet long.
Before using the jig, I, roughly, square the log ends, so the clamp can grab VERY tightly.
When using the jig, I try to find the “sweet spot” to position the log in for cutting. That is, the position it is least inclined to want to roll, as the blade moves through it.
After the first cut is made and the log can rest flat on the table, the jig is even easier to use for the second cut.
Keep in mind, the logs always wants to roll when there is no support on the bottom, at the point where the blade comes out of the wood. If the log does turn, it can be more than a little exciting. It, certainly, would be the end of a blade, at the least. How much the log wants to roll depends on factors like the sharpness of your blade, the size of the log and how well the log rides on the table.
Because of the tendency of the log to want to roll, I make sure the clamp is tight. That, the portion of the log riding on the table, and holding the jig down to the table has worked on several rather gnarly logs and I haven’t had to work too hard at it. However, having run the band saw and learned, first hand, about the hazards of cutting round things through the blade, I am always aware of how easy it would be to spin the log, so I keep my hands away from the danger area, or what would be, if the log spun.
Sleds solve the problem of the log twisting. Some by use of a clamp, others just screw the wood to the sled. With a true sled, there is less likelihood of the log rolling. With this jib, you are the other part of the sled responsible for holding the wood flat to the table. Keep these things in mind.
Keep in mind, if your blade starts running through the wood at an angle, it’s time to stop and tweak the machine, be it by way of a blade change, positioning of the blade so the gullet runs at center on the upper tire, tension or other. A blade running through the wood at an angle is going to pull on the wood and that pull will increase with the angle.
Obviously, the larger the log, the harder you’re going to work. If using this jig, you might want to run a few smaller logs to get the feel of running it.
You’ll find that having the jig clamped to the log is, essentially, just giving the log a straight edge to work with. With it clamped, you could free hand (run without a fence). You’d just have to take care to avoid getting your latest favorite blade near the jig.
If free handing, the closer you get to the center of the log, the less inclination there will be for the log to roll, since there is less gap at the bottom.