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Scraping a 30x84" cast iron surface plate

BrianB

Hot Rolled
Joined
Aug 24, 2006
Location
Shelbyville, Ky
So I was at an auction the other day and decided I couldn't let the 30x84 cast iron plate go to scrap so I drug it home but I am sure it is in need of a good going over. It is one of the plates that has the holes in it for handling and rolling it upside down to print with. I suspect it weighs over 1000lbs though. When printing and hingeing something like this how would it normally be done, get a buddy to help try to drag it? I think I can get it mostly on my 4x6ft granite table by going diagonal.
 
Make a flipper. Look at the first few pages of my booklet and you can see the flipping rig Do-all uses, or if you have a copy of the Moore book they show them in there too. If I were you I would make some long handles to fit in those 2 holes say 4' long and use them to lever it back and forth. Be sure to set it on 3 points for a while if it's been sitting cockeyed for a while. Also get your big rubber dead blow and ring the heck out of it every other time...this also helps vibrate off any chips or crud on it.
Keith bought a bigger granite too. You guys are really making the shops perfect :-) I put you how to use a radial arm drill on another forum when a guy asked about them. Have you ever power tapped with yours? Radial arm drills work super for power tapping. Rich
 
Let us know how this goes! I'd love to get larger cast iron surface plates so I can scrap them in myself, but was wondering the same thing.

We don't have an overhead crane at our shop since all our work is small scale, but one can dream. If nothing else, a small but heavy duty gantry crane could work.
 
I have power tapped some with my Carlton. It does work very well, much easier to tap on it than my Cincinnati.I figured I would make some shafts to put in the holes for handles then I would slide pipes over the outside of them so that I could use slings to pick it up and then spin the plate in the pipes to flip it over. Best I recall the plate has 4 pads for support,I think ideally I would like them to be parallel to the face when it is finished so I could use a precision level off of them to reference the plates plane to what ever it was on.
 
My last trip to China, the shop I was at a machine shop that had several cast iron surface plates placed around the shop. They were about 2 meter square and at one time hand scraped to a degree of flatness. They reminded me of the YouTube video of the Japanese guys scraping those big surface plates they were doing. Very well could have came from there, too. They were well worn from many years of use. I would guess they were at least 40-50 years old if not older. Would love to drag one of them home with me. They would probably ship one to me just for asking. I would have to pick it up at the port of Houston though. That would be the killer!

Ken
 
Dang Brian, Man after my own heart, too many projects and not enough time to do them :) Keeps us out of the bars I guess. I cannot wait to see this one on U toob

Warren
 
Brian another tip and I think you saw me do this, use a lead blow hammer when it is on the granite and pound on it and listen for the same solid thud. If it has a slightly different ring. That spot is open. It maybe bluing up but it's tipping into it.

Remember if it is low in some area's you can tip scrape it too, another trick we talked about at Keith's class. :-)
 
It will be awhile before i get onto this job. I have to get my granite checked first so i know what I am starting with. Also i have way more pressing projects at the moment. Too much to do too little time!! Someday though!
 
You probably already know this but beware the plates sucking to each other when you take a rub.

A younger, foolish me raised my 4’x9’ CI surface plate a few inches while bluing up a 3’ square plate. Luckily no tragedy; lowered everything with the crane and then re-leveled things.
 
On those big plates a lot of times we have it hanging from the flipper and it's leaning on an angle of approx. 30 to 40 Degrees and you sit beside it on a chair and scrape it on that angle instead of leaning over it sitting flat. One can get a bit of a back ache doing it that way. lol.

We would let you take multiple turns....lol.....Rich
 
Or, you could try to get one of those 3 or 4 foot long Japanese hip scrapers where you can reach the whole thing just standing around the sides. Being able to see the spots out there in the middle may be a different challenge. Maybe that's where you need a small kid as a helper to sit out there in the middle of the plate and give you directions. :D
 
My dad did special effects prop making in Hollywood for a number of years and one oh his specialties was making custom fitted leather "flying" harness's. They were essentially a pair of thick leather pants with connections on the sides to mount wires so they can string people up in the air and flip them around.

Maybe I'll have him make one of us a harness so we can "fly" over the plate, lol.
 
Get the harness and I can fly you from the bridge crane. :-) 30" wide isn't too much of a reach though. Doing the mill table on the HBM would be easier from the crane tough. Baily's barn scrapefest!
 
So I was at an auction the other day and decided I couldn't let the 30x84 cast iron plate go to scrap so I drug it home but I am sure it is in need of a good going over. It is one of the plates that has the holes in it for handling and rolling it upside down to print with. I suspect it weighs over 1000lbs though. When printing and hingeing something like this how would it normally be done, get a buddy to help try to drag it? I think I can get it mostly on my 4x6ft granite table by going diagonal.


good thing you put the dimensions in inches...you sure go for the small stuff. Before you start messing with it, you might just want to get yourself an optical collimator, or a set of differential levels, neither will be cheap but given your setup over there might be a necessary investment. Given that size and weight, you might want to verify that it will not noodle on you when you flip it upside held by the handles. Even CI bends under its own weight, but you already knew that. You prolly best scraping it resting on its 3 points and using a collimator to verify flatness. Still, a huge job to get it flat. But hey you are the biggest denier of human limits when it comes to handling the big stuff, I am looking forward to the videos. They all start..."Hi, Brian here! I have no clue what I got into, but figured this much out :)

BTW, no pixtures no proof, just sayin'

dee
;-D
 
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Good luck !

Everything bends quite a lot.
A CI surface plate is very floppy vs an optical table, for example.

For instruction and learning, it would be very very interesting to see how much your CI table bends.
If you lift one part like the center 0.01 mm how much does the corner lift ?

Or put a cigarette paper shim somewhere, and lower the table while observing 2 dtis.
What is the difference ?
 








 
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