02-14-2021, 05:03 PM
Please read to the finish and I will answer your question. I can not speak to the tool you are referring to because I have no experience if them. But please read word for word and do not read anything into it. Also put everything you have been taught aside and do not let it influence you until you have finished reading my reply.
50 years experience building tooling for production. If a fixture was needed to hold a part. or a jig needed to be built so the part could be made, the tool maker was there and it was their job to build it..
So here it goes.
A datum is a line, plain, surface or feature assumed to be prefect. It does not have a tolerance but everything is referenced from it.
The thickness of everything is determined by the distance the cutter head is from the bed of the machine. Therefore the bed of your machine is the datum.
Your cutter head may or may not be parallel with the bed of the machine. Yes I know everyone wants it to be so. but miss locations do happen. In fact the cutter head may or may not be the same diameter form end to end.
I set my knives from the bed using this tool.
It needs to be rotated so the other end of the blade is the same height. and all three blade can be set on the same plane I try for a total difference of .002. by rotating both the gage and the cutter head.
If you have jacking screws fine it is going to be a breeze, if you don't, you are like me, and in for a long afternoon.
Because you are also dealing with pressure rollers pay attention to the height of the cutters before removing them since you do not have the knife setting tool that came with the machine and this will be true no matter which way you decide to pursue.
The same applies to the jointer only the out feed table is the datum.
The tool you posted is good for only one thing here are some other uses for mine.
Moving a tenon jig a few thousandths.
Setting blade height to the thousandths. A quarter inch is .250
Moving rip fence .004 or 1/4th of a 46th
Setting a miter gage for square, my Starrett square is square within .001 in 12 inches. So much for a plastic drafting square nd an eyeball
The indicator id remounted and a thickness move can be measures. If it measures a 1/64 over 3/4, then moving it .015 down will make it exactly .750
You can PM me if you would like more information If you wish answers to what is happening in the pictures post them here for anyone of PM me.
Tom
50 years experience building tooling for production. If a fixture was needed to hold a part. or a jig needed to be built so the part could be made, the tool maker was there and it was their job to build it..
So here it goes.
A datum is a line, plain, surface or feature assumed to be prefect. It does not have a tolerance but everything is referenced from it.
The thickness of everything is determined by the distance the cutter head is from the bed of the machine. Therefore the bed of your machine is the datum.
Your cutter head may or may not be parallel with the bed of the machine. Yes I know everyone wants it to be so. but miss locations do happen. In fact the cutter head may or may not be the same diameter form end to end.
I set my knives from the bed using this tool.
It needs to be rotated so the other end of the blade is the same height. and all three blade can be set on the same plane I try for a total difference of .002. by rotating both the gage and the cutter head.
If you have jacking screws fine it is going to be a breeze, if you don't, you are like me, and in for a long afternoon.
Because you are also dealing with pressure rollers pay attention to the height of the cutters before removing them since you do not have the knife setting tool that came with the machine and this will be true no matter which way you decide to pursue.
The same applies to the jointer only the out feed table is the datum.
The tool you posted is good for only one thing here are some other uses for mine.
Moving a tenon jig a few thousandths.
Setting blade height to the thousandths. A quarter inch is .250
Moving rip fence .004 or 1/4th of a 46th
Setting a miter gage for square, my Starrett square is square within .001 in 12 inches. So much for a plastic drafting square nd an eyeball
The indicator id remounted and a thickness move can be measures. If it measures a 1/64 over 3/4, then moving it .015 down will make it exactly .750
You can PM me if you would like more information If you wish answers to what is happening in the pictures post them here for anyone of PM me.
Tom