We’re having a bit of a debate in the forum on how you should cut notches. Obviously, we’re talking about multiple plies, not single or double layers.
The central question is, can -or should- you use your main cutting tool to cut notches? Those using a round knife have figured out this doesn’t work. Being round, the blade doesn’t cut far enough into the top or bottom layers and can nick too deeply into central layers. So, the question becomes, do you switch to a knife and use that for general cutting and notching, or do you buy a stand alone notching tool?
The contrary opinion is that it takes longer to switch tools but it’s not as though you can cut the notches with the knife as you’re cutting around the body of the pieces anyway. That’s done after. If anything, it seems more unwieldy to have to lug the knife around the table (or move the cut ply piles into it, possibly misaligning them) plus it has to be plugged in using power and the ratio of cuts to energy usage seems wasteful. The hand tool is easily scooted around, needs no power and you align the notcher into the plies without having to move bundles around. I think that there are no, if any, cost savings using the knife. If anything, I suspect using the knife would take longer. Besides, even if the knife did take less time, aren’t the quality gains worth it?
With a knife, it’s too easy to cut too far into the lay, they have to eyeball it and if they’re busy, that’s just too much potential for disaster. What if a given seam allowance is only 1/4″? Your cutter isn’t always going to know (or remember) which allowances are where -and for given sides for each piece? I’ve never had to give a cutter seam allowance information. As though they could remember what goes where on each piece (assuming they even know what each piece is; it’s not always obvious). As JC mentioned, you can buy blades for a variety of cutting depths (1/8″-1/4″) so it is impossible to cut too far into the lay. Additionally, cutting is a higher end skill. With the cloth notcher, anyone can do it freeing up your higher paid cutter to do other jobs. If it were me, I wouldn’t even hire a cutting service that notched with their knife. The very idea frightens me; lose an entire lot because one piece on one side was mis-notched? I’m not willing to take that risk. It didn’t even occur to me that a contract shop wouldn’t use a notcher. I’ll have to remember to add that to my list of criteria.
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