I have received many comments and even a few emails telling me that if I want to get better quality cuts with my table saw, jig saw or even my sliding mitre that if I use masking tape, and cut through that tape, it reduces tear out, which is what causes that fuzzy edge when crosscutting boards.
Well ... I heard the same thing well over 20 years ago and I tried it then a couple of times and it didn't work so I have never tried it since. I guess it's time to try this again with some of the newer tapes and see if it makes a difference and to be honest ... I was skeptical at best that using something a flimsy as tape would really work as a solid backer on wood and give better cuts ... but ... I am always up for having my mind changed and this wouldn't be the first time that would happen.
Watch it on Youtube: https://youtu.be/_9nPFox_n5Q
I armed myself with 2 good quality tapes that I already use in my workshop for a variety of things, first 3M Blue Painters Tape and secondly, a newer tape I have only just started to use Frog Tape ...
Table Saw Tests
The first test would be on my table saw, and to make it worthwhile I needed to use a blade that I already knew would produce tear-out so I opted for that 40 tooth no-name combination blade I have. You can see the results from this blade in the "Zero Clearance Tests" I made recently and you will understand why I had to pick this blade to use.
The medium I was cutting was double sided Melamine, the same material cabinet makers use for things like kitchen cabinets and regarded as one of the top hardest products to get clean cuts on both sides of, and coincidently, the easiest to see any chipping or tear out with.
The first cut I made was with no tape as I needed something to compare with.
The second and third cuts were with Blue Painters Tape and Frog Tape respectively. As expected the top cuts were all very clean, but I expected this because the teeth of the blade are driving down into the material, but when I flipped the board over and removed the tape ... there was chipping and tear out galore on ALL the cuts. For some reason, the Frog Tape produced the slightly worst chipping. I don't know why this would be, this is an excellent tape for painting and giving an extremely fine edge, but as a backer for cutting with a table saw it was not good ... but then neither was the Blue Painters Tape.
Conclusion: Attaching tape gave little or reduction in chipping or tear out on the table saw.
Jig Saw Test
I moved on to the Jig Saw to see if using tape here would help at all. For this testing, I made sure the Jig Saw was set at it's the finest cut. What I mean by this is that some of the new Jig Saws have a small switch on them that re-sets the angle of the blade to a slightly leading, rather than vertical position. The purpose of this is to give a quicker saw cut, which if you were cutting a hole in plywood for a window opening, would be a nice feature and who cares about chipping or tear out there. For woodworking where we often want a finer cut, the vertical position gives a slightly finer cut, which is the setting I used.
In terms of blades, I decided to invest in a new blade and selected what I thought would be a somewhat popular blade, a Lennox Fine Wood blade. In the end, it really didn't matter too much what blade I selected because all I wanted to see was if using the tape would make the cuts cleaner. I also happened to have a Lennox Scroll Saw version Jig Saw Blade which has finer teeth and is really designed for cutting tighter circles, but I thought it would be interesting to see if the finer teeth would make any difference.
For the Jig Saw test, I made the first cut using the Lennox Fine Wood blade and NO tape.
For the next 2 cuts, I wrapped tape all around my Melamine test material so I could see how the tape affected the cuts on both the top and the bottom of the Melamine board. An, of course, the last cut was done using the Scroll Saw version Jig Saw blade, but with NO tape.
Conclusion: As with the table saw the test, the tape made little or difference to the quality of cuts, the tear out and chipping were equal, and with the Frog Tape, slightly worse. Even the very fine-toothed Scroll Saw - Jig Saw Blade with no tape made significant tear out and chipping.
More - The Lennox Jig Saw Blades I was using ALL had UPWARD angled teeth, which means that the underside of the wood being cut will receive the best quality cuts and here again the tape made no difference. I should be noted that some Jig Saw manufacturers offer jig Saw Blades with DOWNWARD point teeth which means these blades will give a clean cut on TOP the wood being cut and tear out and chipping will be on the underside just like a table saw.