Scraping a vertical surface?

Hmm, Overhead welding with 7018 and other fast freeze rods is very close to doing it flat. Just turn the amps down a very little and
keep a steady hand.
Scraping is another matter. I still have trouble getting a nice pattern doing it flat. Getting into dovetails on a base that cant be rotated
takes gymnastic ability. Flaking dovetails in any position is like a controlled wreck for me.
If possible, get some machined angle plates and material for small rectangular surface plates to get into small fits and work with those.
Just learning to get the blue spread correctly and at proper thickness is a learning process.
That will give you time to get tooling and basics learned and you'll have some nice tools as well.
 
While cleaning a the table I pluged the T slots and filled the chanels with evaporust. I then wacked it as hard as I could and saw zero impact tremors in the liquid. No noticeable increase in resistance at end of travel. However there is 0.01 backlash on the traverse. I think the sub .001 movement on indicator is from black scale and pits on the table.
 
When I recondition my Index mill, it started out stripped down when I got it from dad. I did just that turn the base/column on its back, propped it up with 4 x 4 blocks and cribbing to make sure it don't move. Tried to fuzz down the ways. Scraper would not even cut very good from the chilled Meenite castings Index used. Just oilstoned the surfaces and called it good. Likewise on the knee, too. Did a impression check, got good contact at all four corners, don't remember about the middle. Checked squareness with a 20" machinists square I bought second hand and verified against a Starrett electronic height gage that was designed to check squareness and was within .0005" in 20". I could see a little daylight at bottom of the square, but couldn't get a .001" feeler in there. Called it good and went to the next step of checking the gib fit.
 
For most home machinist, if you tear it down and re-oil pocket the flats and v-ways it will work fine. Talking a mill first time scraping i can just about guarantee it will get screw up. I scraped for 25 years in a shop, not on a daily bases, but you don't learn that over night, take all the classes you want you need hands on experience. Start out with a old surface plate and scrape that in.
 
I like to follow up behind when someone who has never scraped before scrape upside down :wink::wink::wink:
Also I have had hundred say you can't learn to scrape in a week, the majority were professional maintenance men and I proved them wrong. Scraping a surface plate is duck soup. Scraping a Knee Mill and or a Jig bore takes skill because your working with a lot more then flatness: Squareness, parallelism, sweep tests, etc. Lots of practice with a journeyman watching.

I have scraped upside down using a mirror laying under the way and looking in the mirror and learning how to move to the left when you need to scrape to the right. When your working on a 10 ton machine and no overhead crane you improvise.
 
I do not consider myself an practiced rebuilder or a seasoned scraper....

We made what might remind some of a Rotisserie to hold the column. We could pivot the entire column so that it was easier to scrape and blue.
The bottom cradles the base and the top has a floating mechanism with bolts to pinch the top of the column toward the cradle.
The entire assembly and column could be laid down with the assist of a gantry, jib crane or engine hoist. The back was flat so that it was stable and wouldn't roll.
While our first build was pretty crude it worked.
Didn't take any pics. Sorry.

On edit: if this is your first rebuild. Please take the solid advise of those above. This is a huge project. Scraping is only a small part. The complexities of the machine tool geometry is much more than a math problem.

Daryl
MN
 
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"On edit: if this is your first rebuild. Please take the solid advise of those above. This is a huge project. Scraping is only a small part. The complexities of the machine tool geometry is much more than a math problem."

+1 THIS. I'm going to pile on with those that caution jumping in. If you've not read the Connolly book it is not only a fount of practical info it is a great test of your patience and commitment. The commitment to read and understand the approach alone lets you know the scraping is just a part of the process. Then the basic equipment like gages, surface plates, jigs etc etc alone is daunting in $$$ and foremost time. It is no wonder this became a lost art because the amount of skill and the knowledge involved. Not to mention the hours and hours of practice alone would make an industry always trying to take labor our of the bottom line deep six this profession. They would much rather you replace a worn machine than fix it. Win win for the manufacturer.

Congrats on your score and saving some old iron from being scrapped. My approach to any machine whether it be a car, truck, or machine tool is to run it and learn to use it first and it will tell me what needs fixing. But that's just me, YMMV.
 
I do not consider myself an practiced rebuilder or a seasoned scraper....

We made what might remind some of a Rotisserie to hold the column. We could pivot the entire column so that it was easier to scrape and blue.
The bottom cradles the base and the top has a floating mechanism with bolts to pinch the top of the column toward the cradle.
The entire assembly and column could be laid down with the assist of a gantry, jib crane or engine hoist. The back was flat so that it was stable and wouldn't roll.
While our first build was pretty crude it worked.
Didn't take any pics. Sorry.

On edit: if this is your first rebuild. Please take the solid advise of those above. This is a huge project. Scraping is only a small part. The complexities of the machine tool geometry is much more than a math problem.

Daryl
MN

Daryle still have all those straight-edges we recovered up north? There used to be a guy named Ed Hadley that Dennis and I both knew who specialized in Bridgeport rebuilding and that idea of the cradle was his. He also had 3 planners set up dedicated to doing the table, saddle and column.
 
It is best to go about it with knowledge and tools ready but some of these machines are so messed up from the factory that
even a bad job of it would be a big help. I started with the lathe compound and even the poor job I did made a huge improvment.
Yes, I scrapped it again later and will also check it next time I tear the lathe down. As I practice and learn my scraping gets better.
Git er done!
 
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