Sunday, August 9, 2015

Fun With Chop Saws

These are commonly called chop saws but more accurately double bevel miter saws (because you change the angle of the cut in two different axes).  The new one has some nice features such as being a compound saw, which slides across a substantial distance, so you can cut pieces much wider than the diameter of the saw blade, and a laser that projects a line onto the workpiece.  There is one annoying downside.  The old Ryobi had a clamp for locking the workpiece against the back fence:
This actually worked well not only when cutting a piece of wood or aluminum in two, but also when I needed to take off a slice of tube or rod.  I constructed a number of fixtures from square aluminum tubes with 3/8"-16 bolts to hold round objects firmly, while the clamps locked the square tubes against the back fence.
This makes it possible to lock down round workpieces quite strongly.  When cutting 1" sections of acetal, all I had to do was loosen the bolts with a wrench, advance the material, tighten down the bolts, and make another cut--all while keeping fingers well back from the blade.

Of course, as the round workpiece neared the end it became more difficult to cut short sections without the blade hitting the end of the holder.  So early on, in fact before the square holders, I started using these steel L-brackets with a 3/8"-16 bolt to hold the rods in place.  The back of the bracket would be clamped to the back fence.

The 3 is the diameter of rod this is for cutting.  Each cut, I loosen the clamp and move the workpiece further into the saw blade.  Of course this requires drilling and tapping a 3/8"-16 hole in the center of the rod.

The new Ryobi does not use the same workpiece clamps.

These clamp from the top and it is more a hint than a constraint.  For my purposes, useless.  Also the right side clamp blocks bringing down the blade at 30 degrees, one of my very necessary angles.  The good news is that unlike the old Ryobi, the new one's fence is flat on the back, so C-clamps can be used just fine.

These are not quite as elegant as the old Ryobi's clamps, but they work and they are general purpose tools.

Finally, you will notice the back fence on the right has a ruler, somethiong I had to add to the old Ryobi.

This is not quite as accurate as what I had created on the old Ryobi.  It tends to cut stuff about 1/16" too long, but I can compensate for that. 

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