Thread: Chipping! experiance and help needed

With the bandsaw and jigsaw it's often advantageous to place it on top of a sacrificial board. Eg. a sheet of ply. This supports the back side of the cut; it's now the ply that's "unsupported" and will chip out.

Ditto with a crosscut saw. Clamp a sacrificial piece on the edge that the saw emerges from and that should alleviate the problem with luck.


FWIW, I can't say that I've had problems with chip-out on the entry side of a bandsawn cut... except when I'm using too coarse a blade for the cut. Or a blunt one. A rule of thumb I follow is: the TPI of the blade should be such that 3 or 4 teeth should be in the cut at any given time. eg. if I'm cutting a 1/2" board, I really want at least something in the range of a 6-12TPI blade.

Alex

What Skew said in general, even for drilling holes, a backer board is a must and brad point bits will give a cleaner exit hole but not always perfect.

For the jigsaw...even with the new Bosch upcut-downcut blades there will be some small amount of chipping...but very acceptable.

With the Cut-off saw you need a high tooth count blade.

Not sure what speeds you can get from the CNC machine, but for engraving, think router speed and router bits

I usually try to control what you call chipping by:
1. as mentioned already,using a backing of sacrificial timber, pressed hard against the workpiece.
2. wrapping masking tape around the cut area. It sounds lame, but you will be surprised how effective masking tape is at this job. Pull the masking tape taut as you apply it.
3. sometimes I slice across the surface of the workpiece, where the cut is to be made, with a sharp knife. I keep this to the wanted side of the sawblade kerf, not the waste side. This has the effect of cutting the surface timber grain and preventing it splintering.
4. for holes that insist on tearing out, I will do a very small pilot hole first right through, then drill through from both sides following the pilot hole.
5. by thinking about the order of doing things, by this I mean I will arrange the order of the various processes so that the cleanest one comes last, and will clear away any tearout etc caused by earlier processes.
6. having realistic expectations. Tools like jigsaws were never designed to give you a smooth finish, ditto materials like plywood.

Arron

When drilling holes you could try entering from both sides. Drill small pilot hole right through. Then drill finished size about half thickness. Turn board over and drill finished size from other side.
I am now able to cut ply with minimal splinters, and laminated sheets without chipping by using a Festool circular saw and track. The saw uses a 160mm blade with 48 teeth. The saw also comes with a sacrificial splinter guard to reduce splintering and chipping.