I got a used CX-329 Smithy mill, (rebadged RF-45), for a great price. The table ways are not ground, although the saddle is top is scraped as as are the base ways and the column. The table ways still show the milling marks, similar to the way the IH mills used to be. I am going to start with the Z slide. I have some Canode #2243 water soluble die spotting ink. Will this work? What is recommended?
I plan on scraping the saddle top, then use that to mark the table bottom. I'll do the same saddle bottom, then use that to mark the base.
I won two 3"granite surface plates at an auction, (one 18x24, other 18x28). I plan on taking one of them to the marble counter top place and see what it would cost to cut a 4" wide slice off of one, preferably at an angle, and use that to spot the column.
I'm not going to mess with the dovetails. I don't have the measurement equipment to be sure that they remain parallel to each other while they are worked on. I'll check them for flatness however just for grins. I'll take pictures as I go.
For my scraper, I had an old piece of 1"x.5" carbide that I brazed to a long strip of steel. I taped the strip to a smoothed flat 3/8" thick oak strip for a handle. I ground the cutting edge to 5" radius and chamfered the top to make it easier to see where I was scraping, (it was a pretty thick cutter).
I pulled the Z-Axis saddle and checked it on a surface plate. I was able to rock it .002" on the ways. Spotting showed that the gib side was only riding on .5" of the way on each end. I appears that the casting sprung a bit when the gib screws countersinks were machined. The biggest problem I had was getting the spotting blue enough to see well, yet thin enough to show the subtle high spots as I got it flatter and flatter. I may need to try oil based ink instead. I had the best luck with my water based by letting it almost dry to the surface plate. I was spotting directly on the surface plate. I don't have a parallel yet. I have a second 3" surface plate that I want to see if I can have a strip cut off of it at the local granite counter top shop, (I'm hoping they can cut it at an angle so I can get under the dovetails when I attach the table ways.).
They saddle came out great. I set the saddle on the surface plate and indicated off of the circular boss that the head seats against and had it within .0005".
I'll get some pictures uploaded tonight. I'm not sure how well the surface blue came out. I may need to adjust the contrast first to cut out the glare.
I just refuse to use the old-fashioned prussian blue dye anymore; it's too messy and doesn't work any better than the Canode ink. Canode comes in many colors and simply washes up so easily in water. 2243 (blue) is probably the best choice to start with.
If you plan to use granite masters, I suggest making sure that you stone with a piece of hard arkansas stone after each scrape before spotting. It's not a big geal for hand scraping but if you use a scraping machine, a lot more burrs can be kicked up since material removal can be much higher. I previously used a cheap silicon carbide stone (typical black stone), but IMHO it's best to use a stone that is least inclined to leave particles behind. Even with careful brushing afterwards, you will eventually scratch the master.
Nowadays, my process has evolved to scrape, wipe off swarf with chip brush, wipe off canode with an alcohol moist paper towel, intermittently lube the surface with an alcohol damp paper towel while I stone the surface, then wipe with a clean alcohol towel, wait a couple of seconds for it to flash off the alcohol, then chip brush ot be sure. The alcohol keeps the stone from loading-up and reduces stone effort/time. we are talking about minimal dampness on the rag(s). It seems to work better to ensure that masters stay scratch-free.
$25 got a strip cut off of one edge of the surface plate at a 32 degree angle from vertical. As indicated in a prior post, I have the Z axis saddle finished. I have the table saddle finished now as well.
The table saddle top surface was the best so I started with that. One side was pretty symmetrical, but had a dip in the middle. The other side ramped up 2.4 mils. The dip was the same height as low side on the opposite way. I'm probably not aggressive enough with the scrapper, because it took forever to scrape down the extra .0024".
My arms were ready to fall off from hefting the Z axis saddle on and off the surface plate for spotting, so this time I used the dovetail strip I had cut off for spotting the table saddle.
I measured what one hard scrape took off and it was barely .0002". I took it within .0005" and then worked on the opposite way. I got that within .0005" of flat, then used the surface plate for spotting the rest of the way.
I am using the gib to spot the gross imperfections in the dovetail and taking down the biggest high spots. The table comes next.
I WILL get some photos posted as soon as I find the proprietary camera USB cable!
The bottom of the saddle was high .004
Another tidbit that I learned about scraping.
I started out by using a silicon carbide stone to deburr in between spottings, which still scratched my granite master. Switched to a hard arkansas stone after realizing that the silicon carbide stone was leaving behind debris that even brisk brushing didn't always remove. The scratching situation was better.
What seems to work best is a deburring file, to make your own do this:
8-10" double cut flat file with handle removed. Use an old file if you have one. First grind a 40 degree safe edge along one side and grind a 90 safe edge along the other side. Now use a whetstone to dull the file which will include deburring your safe edge work. The dulling is needed otherwise the file will leave its typical cut scratches. The purpose of a deburring file is mainly to "knock down" burrs and to remove larger burrs. Works great and can be used for any dovetail. This was a recommendation that I found in a tool reconditioning book. I will never use stones again for this job.