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Scraping a vertical surface?

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agfrvf

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#1
Been trying to research scraping a vertical surface and could not find anything but a special vertically mounted granite surface plate. I have a mill I want to inspect and possibly scrape if I have to.
 

Kernbigo

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#2
i did a bridgeport one time and laved it down(the machine) to scrape the back flats
 

chips&more

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#3
I can’t stick weld upside down to save my life. I had the whole neighborhood over one time to help me turn over a boat trailer so I could weld the underside. I was the talk of the neighborhood from then on. Like said, just turn it.
 

Dredb

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#4
I have Connolly's book, wherever possible the parts are laid flat, it's just easier that way.
Dredb
 

FOMOGO

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#5
I can’t stick weld upside down to save my life. I had the whole neighborhood over one time to help me turn over a boat trailer so I could weld the underside. I was the talk of the neighborhood from then on. Like said, just turn it.
Trust me, your not missing anything. I can run a decent overhead bead with stick, but it's never any fun. Nothing wrong with flipping it over if possible. Mike
 

Bob Korves

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#7
Been trying to research scraping a vertical surface and could not find anything but a special vertically mounted granite surface plate. I have a mill I want to inspect and possibly scrape if I have to.
The information you are looking for is in the machine renovation "bible", Machine Tool Reconditioning, by Edward Connelly. You can find it here on this site:
http://www.hobby-machinist.com/threads/connelly-on-machine-tool-reconditioning.41802/

That said, I suggest strongly that you do not start out learning to scrape and rehab a mill by reading part of the book and getting on with it. You will not be very likely to have great results doing it in that way. It is a bit like a guy who has never held a screwdriver in his hand, and has a plan to completely rebuild the engine and transmission of his car, including all the machine work, all as part of his first project and by himself. It isn't likely to turn out well.

I do recommend you read the book and make sure you understand how to properly test and assess your mill's current condition, and read and understand the sequence of operations used to get the geometry of a mill back to flat, square, and parallel like it left the factory. Hint, that sequence is almost certainly not what you think it is. After getting an understanding of the process and how to prepare for the job, then make sure you are up to the renovating task, which can be long and difficult at times, and even more so for someone new to the work, who WILL make mistakes.

The best bet is to find someone who has a lot of real world experience with doing this work and try to get him or her to mentor you for the project.

It is far better not to start rehabbing the machine at all if you are not truly up to doing the learning and hard work required to complete the job to a proper result. That usually ends with frustration followed by a basket case sale.

Machines do not need to be perfect to do very high quality work.

Scraping vertical surfaces is not required, and should be avoided if at all possible.
 

benmychree

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#8
In the shop where I apprenticed there was a guy who did scraping "back east" He told of a job where he laid on the floor and scraped overhead on a surface that the "powers that be" did not want to rig and turn over. Things can always be worse, but at least for smaller machines, it is always best to have your surfaces to be scraped "in position", that is, in a horizontal position.
I quite agree with Bob in that machines do not need to be in perfect alignment to do acceptable work, even very high quality work. Perhaps we impose overly high tolerences on ourselves when much lesser limits would suffice. Think of the phrase "perfect enough".
 

agfrvf

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#9
I can see original scraping marks on the machine and spindle accuracy when new was 0.003". I know the .0001 changes if you blow on it. I just want to see what I have and be ready for the worst. I litteraly paid scrap value on the machine. It is cleaning up nicely. My dial indicator isn't moving more than one thou so its in spec as far as I can tell.
 

Bob Korves

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#10
Assuming the mill is still assembled:
Before measuring things, make sure to adjust all the gibs to their best possible fits. Otherwise you will find geometric problems that can be pretty easily brought closer to what the machine is capable of. For instance, if the knee gibs are loose, then the knee will hang downward at an angle (sag) and that will leave you thinking that the top of the knee and the saddle are badly worn as you move farther from the column. As with machining, lock any axes that are not actually moving. You will then see the geometry more clearly, and it will correctly show less wear. Also note that if you measure from the spindle straight down to the table, and then traverse the table left and right, It might show a very good reading for the entire travel even if the table is actually sagging badly at the ends. A perfect curve will show no needle movement in that setup. Shake the table fore and aft at the table ends with the locks loose to feel how much play you find there. Repeat up and down. With the table at the center, tighten the locks and then loosen the locks just until the table will traverse without much friction, and then see how much the friction increases closer to the ends of the travel, and how much you have to loosen the table locks to reach the ends.
 

tertiaryjim

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#11
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.
 

agfrvf

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#12
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.
 

4GSR

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#13
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.
 

Kernbigo

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#14
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.
 

agfrvf

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#15
I guess I will start with my chinesium HF cross slide vice. I don't think I could do anything but make it better.
 

Richard King 2

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#16
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.
 

Uglydog

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#17
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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C-Bag

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#18
"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.
 

Richard King 2

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#19
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.
 

tertiaryjim

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#20
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!
 

Uglydog

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#21
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.
Yes, the camels cleaned up pretty well. I'm still looking for a plate large enough that will allow me to reliably qualify how flat they are. I've just been flipping them. They come in pretty close.
I didn't remember that the cradle was Ed Hadleys idea. Thanks for the reminder!
I should have purchased that planer from you!! However, I didn't have space then. Still don't. ... One of lifes regrets.

Daryl
 

Richard King 2

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#22
My wife wants me to remodel my garage up at our new cabin in Hayward WI so I can teach classes up there in the summer. Scraping class and go fishing for Muskies class...lol My place is near Mystic Moose Resort and I have plenty of room plus students could double up at the resort.

Or maybe have a weekend for the Upper Midwest club.
 
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