complex scraping alignment approach

Hi,

I'm continuing work on my Van Norman 22LU machine.

So far, the column is scraped, the knee back is scraped, and the knee flat way
is scraped.

The top of the column (bearing surface for the ram) is scraped, perpendicular to
the column face.

I'm not certain how to achieve multiple scraping goals while scraping in the ram.


The ram sits on the top of the column flat ways, has dovetails and then the
cutterhead mounts to the side of that and rotates through horizontal/vertical orientations.

picture is of underside of ram, showing ways.



There was a fair bit of uneven wear on the ram's flat ways, so I have been scraping them.
However, the alignment is fairly challenging-- the ultimate goal is the two flat ways
should be in a plane and perpendicular to the side of the ram that the cutterhead mates to.

I'm struggling a bit with how to achieve these goals concurrently and efficiently.

I have so far scraped "straight down" on the ram flat ways and have therefore taken out the major central wear and have good blue coverage with a 36" dovetail straightedge printing. However I am having trouble holding those two surfaces in a plane, both longitudinally (length of ram) and laterally (across ram).

I have made some scraped parallels and have printed across them. This shows some uneven printing leading me to conclude they are not parallel.

I have bolted a scraped angle block to the side of the ram, and used that as a reference plane with a DTI to measure as well. This shows some lack of parallelism (maybe .0005" lateral tilt and .001-.002" longitudinal?) but hard to be confident of a long arm projection of a Noga indicator holder.

The bottom of the ram in the center was originally planed and still shows the planer marks. It is not a precision surface so not directly usable as a reference. I could of course scrape an area there perpendicular to the side of the ram as an intermediate reference.

This part isn't small (400lb or so, 30" long, 10" wide) with no nice flat top, so not easy to precision level to make it easy to level and use a precision level to translate measurements. There are a few places on the ram casting top where I could possibly attach leveling points, maybe that would be a good approach.

I tried putting the ram back on the machine to evaluate whether I could blue and print it that way, however the gib fit is tight enough and the piece is big and heavy to maneuver, so by the time I got it on, I wasn't confident of the accuracy of any ink transfer I would achieve.

SO, any advise on the procedure for establishing these alignment constraints while also scraping for bearing?

Thanks,
Phil

Sounds like you need a Kingway gauge or a variation of one. maybe Richard will chime in


Sent from my iPhone using Tapatalk

while visiting the reiden factory i saw they were delibetately scraping out of straight/parallel to alow for all kinds of sag.

I would set it up on a surface plate with the flats up using just 3 jacking screws
A height gauge and a bump guage should tell you what you need to know
Personally I'd scrap it right there on the plate

Dian has a good point about not scraping to perfect unloaded geometry it will sag when flipped over and assembled
Knowing how much to lead it is a art and a science
Pretty sure it's why the pros get the big bucks