Myford Super 7 - bed - part 1: initial measurements

I have now finished the painting of all parts, including the bed and went on to the evaluation and restoration of the geometry of the machine No. SK 92574

Part 1 here covers the intial scraping and measurements on the top (flat) ways of the bed as well as the feet.

Part 2 to follow will cover the vertical ways, then part 3, 4 and so on the rough-to finish scraping and "after" measurements on the flat ways, then the vertical guides and lastly some thoughts/wrap-up of the process so far

The bed was of course very rusty as shown before, and I had to remove this first. To do this I made a couple of passes with the scraper over the bed and light stoned all machined areas (to remove any possible burrs/dings). There were some pitting on the flat ways towards the tailstock, but most went away when I finish scraped them. Very happy so far. I think it is evident that the machine has seen only light hobby use. It turned out it wasn't much worn, just a 2-3/100 mm (ie. apprx.1/1000 of an inch).

My take on scraping the bed is of course not the normal route, but I wanted to show this as an alternative to send it off to grinding, which for some might be out of reach economically. Arguably it is better I guess, at least a pro job, and easier/doesn't require the "scraping skills".But, scraping the bed like I try to show shall also be good enough and get you to an accuracy well within hi-end tool room specs.

As far as I know, most new modern machine beds are ground, but the saddle and other pieces are scraped or at least in some ways fitted to the bed. To avoid stick slip, provide lubrication and built-in longevity, scraping and so called flaking are methods for these parts/purposes. The exposed surfaces, like the lathe bed, can of course also be scraped , but to avoid trapping dirt are (usually) left smoother than the un-exposed surfaces.

Methodically working your way through the different steps in a proven manner, and in this case with simple tools like the hand scraper (didn't use the BIAX power scraper) and indicators, although maybe the big granite is not usual in every hobby shop (but this is also not really a neccessity.. just convenient), will also yield good results.

In the midst of measuring/scraping I thought about leaving the headstock area alone, which would also be OK. However, in the end I scraped it though, but this wasn't really neccessary. Pros and cons can be discussed.