Been there. Squirrely forging on an antique machine to produce a frail part full of close tolerance fearures. Tip, I used to duck tape the end of the Pi tape to the part and jog the table around full circle. Untape the tape and take the reading. The tape takes its wrap under tension and full control
i used about 12 indicator magnet bases located on a magic market line drawn on the circumference of a 160 inch spur gear once. pi tape sat on the bases located on the line. gotta do what ya have to do to get the job done. Af. engineering right?
@@ChrisMaj I remember number years ago Keith Fenner was talking about those tapes but then really get into that much detail if I can remember but thank you keep up the great videos
Sorry to be off topic but does anyone know of a way to log back into an Instagram account? I somehow lost the password. I would appreciate any help you can offer me
@Douglas Jamison Thanks so much for your reply. I found the site thru google and I'm waiting for the hacking stuff now. Looks like it's gonna take a while so I will reply here later with my results.
@@trace12345678900 I used to do there frames thay were fun forgings then cleaned up then cut in half and pined and bolted back together and machined it had a bunch of angeles and grooves the groove on top got 1/8 X 10. Stanless friction roles into the grove and had to maintain . 015 between then machined on both sides with angeles I miss working on them
Place I used to work made big segmented rings for GE we had a Betta VTL from the thirties they did all the turning on. We would start with a ring of a smaller diameter and cut it into a bunch of brick size pcs. The would get rough machined and then assemble into a larger ring and turn on the VTL
Fun reading all the GE guys' comments. Real nice parts. Used to work at Mohave Generating Station of Southern California Edison (Laughlin, NV). 825 MW cross compound turbines. I never could understand how all the casing internal detail was machined. GE man told me, "lt's not the problem you think it is. Just finish mill the casing castings (May have been forgings. Not sure. I think steel castings tho. Steel casting is a bi___, I read) on a big planer mill. Drill, mill all the casing bolt holes. Then do rough machining on only the halves. Then torque 'em together and do all the finish machining. Nothing to it!"h
Man, please... Put your cam on a tripod and let it run... 3 hours, 5 hours, 7 hours... i would watch every minute. Your videos are the best, but waaaayyyyy to short.
Chris, for the OD maybe you can use a blade mic to measure the thickness of the wall, pretty sure you got that ID much easier. And then, ID + (wall thickness x 2) = OD
@@tuantq06 - Haha. You never know. My Son runs a hi end cabinet and furniture shop. Got a man from the union, didn't know how to add and subtract fractions! My Son was patient for awhile but finally told him, "Man. You gotta learn fraction manipulation. You can't call yourself a cabinetmaker, woodworker or millman unless you can do it.
@@ChrisMaj Where you're working at reminds me of the first job I had working in the machine shop that made parts for steel mills and heavy industry. Those were good times! Plus it's awesome to see a fellow craftsman at work!
how much "out of roundness" did you encounter? same with parallelism? was stress relieving a step not shown? additional...i bet that thing resembled a "Pringles" potato chip when done, warped and egg shaped.
spot on as always...are you making curly fries on that pass? lol Stay safe One question is how much will a part like that " move " with you hogging out the ID
Je ne sais pas exactement quelle est l'utilité de cette pièce Mais j'aime depuis mon jeune âge voir toutes les opérations de façonnage, tournage, fraisage, usinage,polissage, des métaux, un métier très professionnel et de précision. Il suffit que l'axe de rotation ou la fraiseuse soient inclinés d'un petit degré pour que le travail ne se réalise pas comme prévu.
Thanks for this great video. I was turning a big diameter ring on VTL, material : stainless steel, 56" diameter, 0.5" thick wall, 3.5" height. After roughing I.D found .100 oval. After the roughing the O.D got .400 oval. Any suggestion from you?
Pi Tape is 0.01in (0.25mm) thick spring steel tape has graduations and numerals engraved and acid-etched on a ground surface. Vernier scale permits readings to .001in (.025mm) diameter; accuracy to ±.001in
If you keep those micrometers too long on hand, they will expand. It’s best to keep those in same room, where lathe is so that temperature is not too cold for example. But it is easy to calculate temperature correction in mm. With steel 0,000012*temperature difference in celsius degrees*diameter in mm=how much to correct your reading from micrometer. Something like that. We have even 2000mm outside micrometer and every size below that.
Great stuff, Chris, as always. I’m curious - what determines when you use lubricant/coolant? Is it related to speed and feed? Or desired/required finish? Specific tool geometry? Or something else?
It is possible to buy an outside micrometer for measuring, that pi tape should be banned, when we were turning journals on crankshafts on 2 stroke engines-on site- we were using big micrometers or a faro arm for measuring, throw that pi tape thing out please, nice work by the way...
Micrometers are nice but they are crazy expensive and on large diameters they are also tricky to use. Pi Tape is easier to use on taller pieces. Say what you want, but they are damn accurate if you know what you doin.
@@ChrisMaj If you know how to use those big micrometers they are the best, it tskes around 2 years for a good machinist to know proper use of big micrometers, in the maritime world when you are measuring journals on crankshaft’s e.t.c i think the oem superintendent would actually not allow that measuring device, i never seen it in use on-site, never heard the lloyd ins.guys mentioning this device but maybe it has it use somewhere but as i see it , it’s and old method and we have better ways of measuring today. So learn how to proper use a big outside micrometer, its all in the fingers and the position of micrometer, never hold a big micrometer in vertical pos. Just an example, there are alot of things to consider when u measurer with big micrometers...
Pi tapes are used extensively in the aircraft industry and all sorts of large OD measurements. They have a vernier, are super easy to read, and quite accurate.
Ohh man. Face grooving in plate just sucks. Cant break that chip at All haha. I just did a video where i did some face grooves on some flamecut plate. And I never really got the grooving chips under control.
@@Tugabud2 I'm the one who's arrogant? You might want to check your comment. This isn't a learning channel, you want to watch it, you watch it. You don't fine with me.
