Lol and glad only once was enough.

Knowledge is KING .

@@wesleymonske8103 Love is the THING.

I learned the black art from old Germans and Dutchmen. They would never be caught with a Bix or a carbide tipped scraper in their hands. Myself, I preferred carbide, but always finished out with a carbon steel scraper (usually the last four or five passes when we are splitting the dots). Most guys hated the job, but I loved to scrape and cut surface plates. It took me several years to just learn to read the dots (if done right will really save a lot of time). Those old men would have had a stroke watching me with an electric scraper. My chips were often smoking

Nice smart comment . Well done .

That sir is sound advice and not nit picking in the least. If that table goes south, east or west it's gonna hurt big time!

I value this comment too. I have rigged part time for 40 years and seldom considered your concern. I intend to heed your advice. I have a 3T gantry with chain fall set up very similar to Keith's in my hobby shop. I work mostly alone. The chain fall operator chain is prone to catch on the loads unlike a hoist that stores its surplus chain in a bag. I didn't expect that issue when I set up my hobby shop. That chain grab can happen suddenly. Doing his demonstrated operation could easily prompt the load shift that you warn about. Retired tradesman are still inexperienced enough to need additional training. I had a seemingly endless supply of one time use straps. A vendor shipped precut stock with a new strap on every piece delivery. The lathe operator collected them. I cleared out his matched inventory giving dozens of them to my boys. I assumed that I would stock up for myself, but suddenly decided to retire. I have a large inventory of mismatched straps and slings. I regret giving away those straps to the boys. Now I will have to buy my own!

there is a gauge used to judge the quality of a scrape job (assuming that everything is flat and all angles are brought together well). It's really nothing but a piece of .03" or .06" gauge stock that is roughly 2 inch square. The center will have a one square cut out.. You lay it on the surface about count the dots. A machine way should be between 15 to 18 dots, but not all dots count. Your looking for foot ball shaped dots that are about 3/16" x .10". Round ones under .125" don't count, and anything bigger than .25" means you're not done. Holes in the pattern also say you are not done. When you start seeing a majority of small foot ball shaped dots, then it's time to start picking. This is also the time your reading skills jump out at you. You don't cut anything out, but you learn to split the dots and even then not every dot gets cut. That's also when that forged carbon scrapers jumps to the top of the list. Lastly; it's an unwritten rule that you never ever touch a scraped surface with your bare fingers. If someone does this, you'll see it on your next cut.

Bill, where do you buy your microfibre from in the U.K?

@@iantaylor5579 Hi Ian. Amazon have a good selection here. Bill B

It makes one wonder if the initial process could be automated in some fashion.

@@tsmartin Exactly my thoughts, with laser scanning to identify the high spots and report back a map of the surface irregularities? 🤔 I guess such a system MUST exist nowadays?

there some tricks to scraping with a power scraper. First of all keep adjusting the hight till you get comfortable. Then measure that hight and write it down. Another guy will be different. The bad ones are the ones you have reach way out there, or scrape from an odd angle. Usually vertical. Dove tails can be a pain, and you always get busted knuckles. Forget the power scraper as it's too hard to control at angles. Gibs are easy once you figure out how to hold it in place. Most good men don't use a power scraper, and will not work with somebody using one. I can do either, but always finish with a hand scraper. The thing about a power scraper is you must learn to control the way you scrape first. You cut in a small circular pattern keeping the blade moving in one direction. I go right to left while reaching further out all the time. I practiced on an old 12" x 18" cast iron plate till I got the knack. Once you got it the rest is easy

I think the blue would make the table stick to the surface plate pretty good. I've done that with a little ground fitter's rule that was 18x4 and it stuck to the plate badly enough that it had to be slid sideways off the plate. When things are flat you can feel the air between surfaces until it squeezes out.

I think he trusted that the grinding service did their job. Likely they have validation equipment of much higher precision than what Keith has, and likely they certified their work. And as mentioned, it would be very difficult to move or get the pieces apart due to stiction or 'wringing'.

@@kindabluejazz I agree.There was no need at al, to scrape that table.

@@JaapGrootveld His reasons for scraping had nothing to do with making it flat - he explains why he did it in the video. You of course are free to do whatever you prefer for your own equipment.

yes not good for headphone user

he lowered the volume on purpose, because the scraper is loud

0.255 lbs per cubic inch, I am going to guess 800 to 1000 pounds.

Go up to his name above the 224K number and click on this to go to his channel index. There look for the videos about scraping or any other subject of interest. This is the best way I can tell you how to find them.

Not Keith but 2 things help to keep the parallelism. First, you're scraping equally across the table, so the high points should remain to describe a plane parallel to the opposite surface. Secondly, scraping might remove .0001 in a pass so a single pass isn't going to change things a lot. You'd have to take a bunch of passes to change things across a table that size.

@@russkepler Thank you, so the changes are negligible.

Would be interesting to hear about your ideas on scraping and such like you mentioned in your first paragraph. Really hard to find this dying knowledge (i.e. tricks and techniques you or people at a place like Monarch used).

@@JFirn86Q Like I said I learned from old German and Dutchmen, and they got me going. They were extremely picky about the pattern quality, and often picked my work apart. They rarely used red or orange lead, and used nothing but High Spot Blue (the kind that wouldn't wash off). The one thing I really didn't learn much from them was scraping bearings. They were good at it, and I wasn't! I had to learn that one on my own, and still wouldn't call it great. Yet good enough to get by with. The trick with scraping is to learn to read the dots (or pattern) when a good pattern starts to show up. Not all dots are the same, and you can spend a lot of time cutting them out. Later in life i learned to read the dots much better, and only cut about 30% of the dots. A few years later I was introduced to water based stuff, and learned to work with it. A year or two later I learned to leave the water out, and use a very light weight spindle oil with pure mineral spirits. That's when i knew my time had come, and really got serious. Then I was tasked with undoing a couple bad scrape jobs on rotary table tops. (you actually can get by with murder on a table top once you learn) A guy I was learning to read by looking over his shoulder showed me tricks with stones, and pure spirits and a little light oil. The stones were made of used thread grinder wheels (white, orange, and red mostly). You make the stone do the work and break up the pattern with the scraper. (sounded backwards to me, but it works) That was from a guy named Steve, and trust me he was very good! I get caught standing around and inherit all the surface plates in the building (both granite and cast iron). I find I also get two near new Bix scrapers and a small light duty one. Can't make them do anything right, and a friend that scraped for Monarch Lathe Company showed me what I was doing wrong (actually showed Steve and another guy named Norman. Now I'm really going at it with the Bix, and my boss is a nervous wreck! This guy was good. A little practice on a junk plate was all I needed to learn the circular pattern. Then he showed me how to pick. Now I in a different world and then he told me the Bix was OK for picking the pattern, but also too heavy handed. I drag out the little one, and we put a reostat in front of it to adjust the speed. I could now pick with an electric scraper well. The trick was in reading the dots and finding the real hard spots, and then cutting them apart in certain spots. With that knowledge Norm gets a rebuild job of a Heald Gauge Grinder. Somebody had been in there before Norm, and it wasn't good. I offer Norm a hand at rubbing the Vee & Flats and now I'm scraping with him (our first job together). On down the road it starts to look real good. I checked the pattern with my gauge, and my head is two feet in diameter. But how to you know if the flat is the right hight? I just don't know for sure. I go and ask Steve, and he comes over. Looks at it (we did check it with the Kingway levels), and comes back with a wood box and a set of Jo Blocks. His tool was similar in concept to the Kingway, but used Jo Blocks and a dial indicator. We had been using my Inter-rapid .0001" indicator. Steve checks the ratio of the flat to the center line of the Vee, and sees .00025" error in four feet+, and then goes back and gets a .000050" indicator. All I know is that my readings and Steve's are indentical. Steve looks up at us and says it'll get by! Norm wants to scrape some more while Steve is on the other side of the shop laughing at us!! (Steve later told me got the .000050" indicator just to jack us around) I turn the slide upside down and break the glaze with the Bix. Then a couple days later we have the slide done on the bottom. Now comes the top side and the dove tails. When done we end up with a grinder better than all they have except for a Moore Jig Grinder and that difference was very little. All of the above was a mistake! Boss figures out that Norm and I can undo most anything (nope!). I'm back on the surface plates, and here he comes to take a ride with him (this was always a bad sign). We go out to a 4360 Devlieg Jig Mill that is torn down to the X axis. Norm's at lunch, and the guy running the machine next to this comes over and says I missed all the excitement. Norm is madder that hell, and has ran everybody off! I get along with Norm very well, so I just laughed. I see right away that the W axis has been Mogliced, and here comes Norm. He says "am I glad to see you!" What's wrong? The W axis is out .009" and he doesn't know where to start. W axis must run parallel to the Z axis (+/- .000050"). I get a felt tipped pen and we plot it, and find it's really almost .010". I tell him we have to do this in layers and then scrape it flat. I drag out the Bix and start cutting it real hard (chips are smoking). Four hours later we are within a thousandth. We need strait edges and seem to be constantly sharpening scraper blades. Moglice just eats up scraper blades. At the end of the next day were almost done. Boss comes by two or three times a day to see if we need anything, and buy coffee. We set the W axis table back on and button it up for a check to see what the table top looks like (it has to be within a tenth), and it's out a couple tenths. I fix that in about three hours with the Bix and a pink stone. I'm done and Norm is happy. Tell Norm he can save my butt on the next job! I come into the shop one day, and across the way from me is this huge Blanchard grinder. They are working their butts of trying to tram it in and get a good pattern. I stay away from this thing. After two weeks they give up (machine was rebuilt by some rebuilding company outside). One morning my boss says to see what's really wrong with it. I hate grinders! I pull the table to see what's really going on. Clean it out only to find they scraped it .0075" out of parallel (as best I could measure). Got nothing big enough to rub it, and by now is pretty nasty. Boss gets a kid to help me, and I give him hell. Where's Norm? Kid is lazy, and doesn't like to get his hands dirty. Boss fires him (he's one of the guys Norm ran off). Brings down two black guys and they work like they are killing snakes!! After about six weeks and two new lube systems plus a real nasty scrape job. I'm done. Machine runs great, and I never want to see it again! Told the boss that somewhere along the way we have to scrape the vertical ways and wheel head, but told him to wait till I retire. Just one machine right after another

@@garytotty3971 Fascinating. I appreciate you writing down what you've learned. Thanks for sharing the stories too. It's becoming a lost art I'm afraid. Not many teaching a new generation these techniques. Machines are all becoming throw-away sheet metal boxes using computers to compensate for error. I've acquired some old machines (monarch 10ee, jones & shipman 1051 cylindrical grinder, kearney & trecker 2CK mill, moore universal measuring machine, taylor hobson talyrond #2, B&S 1236 micromaster, archdale 38s radial drill, and others) that I want to fully restore to be better than new if able - which is hubris, but gonna try.

@@JFirn86Q I started life as a machine repairman, but when I changed jobs the scope of work really narrowed. Later I went into machine building, and this was where I needed to be from the start. Used to keep note books on the machines I worked on, and also ones that I built. Gave them all away to guys I had for an apprenticeship. Building machines was fun, and for me anyway I looked forward to going into work everyday. I built machine centers for about five years, and I really liked doing that stuff. Learned to work close scraping surface plates and machines, and once you learn to work close it easy. The last ten years of working, I ran this little bench reverse engineering machine parts, and rebuilding them. This was really fun, and no two jobs were the same. There are things I can get by on but wouldn't say I'm great at. Cutting gears was one of my weak points. I can get by, but wasn't great. I hated grinders, but most I could get by on without too much of a problem. I was pretty good with hydraulics, but have seen better. Lube and air systems was what I was probably the best at. Machine tool alignments was something I was better that 90% at, but you had to be that way. Having had to work on this stuff when it broke down; I learned to make my systems user friendly instead of taking the cheaper and faster route. My lube system would tell you where to start looking before you got a wrench out of your tool box. Some didn't like that, but at $300K and hour they payed for themselves with the first break down. Most machines are not set right from the start, and with this you are constantly fighting with them. Of course some will never be that exact. I've had scrape jobs that were almost impossible to get to that magic number, and some just fall together. I once had a Browne & Sharpe universal gauge grinder that liked to drove me and Norm insane. Ways were too narrow for a long strait edge, and later we find out that the machine was never plain'd right from the start. I could have stripped it and sent it up to Viking for a good grind job, but I'd still have to scrape it. You never want to have to scrape a ground surface if there is a way not to! Then after we finally got the ways as close as we could; we find other problems that had to be dealt with. Then I find a lube system that was non functional. Like we were on a merry go round. Never been very impressed with anything from Browne & Sharpe. What I felt was going to be two to three weeks ended up being three months! Someday I'll tell you about my adventures in robotics.

You can usually get closer to flat scraping than with a grinder. If you want flatter than lapping is the way. You don't normally want a lapped machine table though because it will be highly prone to dings causing high spots and can create a lot of stiction to other flat objects. It is easier to slide something on a scraped surface than a ground surface.