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Cleaning & Stoning Bridgeport table

table will in general rust faster than you can stone off metal. you dont push down hard unless you feel bur
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i used regular bench stones coarse and fine. if rusty i use coarse. if not rusty i use the fine stone. i also use a reamer stone if i am making small parts (6" or less). again take a part 6 sq inches or bigger, measure and try to stone off .0002", you will be there awhile.
 
Rarely use stones on my machine tool tables. I Use a burr file normally. Stones I use primarily for fitting mating parts, after I hit them with burr file.

Best Regards,
Bob
 
Rarely use stones on my machine tool tables. I Use a burr file normally. Stones I use primarily for fitting mating parts.

Best Regards,
Bob

in my experience a abrasive stone is easier to control not taking too much off. i go by feel of stone when moving along surface. again take a 6 sq inch part or bigger, measure and try to stone off .0002" it is not that easy to do.
 
take standard polishing stones and try to polish mill marks off a part.
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mold makers use plastic stone holders and like a pencil eraser rub back and forth on part to polish. you should all try to do at least once. definitely takes a long time to deliberately polish metal or remove mill marks off a surface
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i have also used cratex rubber abrasive sticks on a lathe. like a abrasive pencil eraser. takes a lot of time to deliberately remove metal
 
in my experience a abrasive stone is easier to control not taking too much off. i go by feel of stone when moving along surface. again take a 6 sq inch part or bigger, measure and try to stone off .0002" it is not that easy to do.

A burr file is specially designed to remove only the burrs. It is a file that has the teeth lapped flat. It will remove burrs down to the surface but not below.

Edit: It also does not introduce abrasive grit on lathe ways etc. I used to use a stone until an old tool-maker showed me this method long before I had machines of my own.

Best Regards,
Bob
 
Mineral spirits or WD40 and a ~400 grit stone is what I always used for ding removal. I worked on the same Giddings and Lewis boring mill for 15 years nearly every day and to this day there is no deflection when a .001" graduation dial indicator is run over the table from ends to center. Do the job well and there will be no damage. If you grind away like a blind and senseless jackass then you will probably do some damage.
 
A burr file is specially designed to remove only the burrs. It is a file that has the teeth lapped flat. It will remove burrs down to the surface but not below.

Edit: It also does not introduce abrasive grit on lathe ways etc. I used to use a stone until an old tool-maker showed me this method long before I had machines of my own.

Best Regards,
Bob

you worry too much about abrasives. rust is abrasive, steel and cast iron chips is abrasive. a little sandpaper on a lathe to remove .0002" is standard especially longer parts that have a slight chatter finish marks on them. not everybody makes short rigid toy maker parts
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mold polishers will generally tell you you need a abrasive stone with small contact area like 0.5 by .125 or .25 by .25 to develop enough pressure to remove material relatively fast. if you could remove material with a bigger stone they would do it but it requires more pressure that average person can push down comfortably.
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a bigger stone flat on a surface removes very little to those who have tried many times to do
 
Mineral spirits or WD40 and a ~400 grit stone is what I always used for ding removal. I worked on the same Giddings and Lewis boring mill for 15 years nearly every day and to this day there is no deflection when a .001" graduation dial indicator is run over the table from ends to center. Do the job well and there will be no damage. If you grind away like a blind and senseless jackass then you will probably do some damage.

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bigger fixtures and parts weighing tons i use a coarse stone for rusty badly dinged stuff. if relatively clean and smooth i use a regular fine bench stone. many a trim pad i have cleaned multiple times and it still probes within .0002". done that maybe a few thousand times at least
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trim pads are used when i want 3 or 4 spots within .0002 to mount a part. trim pads are bolt on blocks you mark up with a marker and remove .001 to clean and then indicate to confirm within .0002 and if more than a meter apart usually tolerance is more like .0003". never know anybody to trust a table to flatter than .001 anyway.
 
I've tried to purposely remove tooling marks in metal parts and also polished a few injection molds in my time, it does take a while even with a small stone and a lot of finger pressure. A large, palm sized stone (especially a fine India) will not remove measurable amounts of metal if you're using a light touch. It doesn't make the surface flatter by bearing down on it, you're only "feeling" for raised burrs and knocking them down until flat. YMMV.
 
Cleaning & Stoning Bridgeport table

+1 on the precision ground stones. I made a few sets of these stones (about to make a few more) after watching Robin’s video. I use them almost everyday in the shop.
 
some of you obviously never used roughing or rubbing stones
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these are used when you have steel sole plates 1.5" thick of many square feet that might be very rusty and you will set machinery on weighing tons.
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you need to remove rust and any concrete or what ever is on then relatively fast. if you use a fine stone you just clog with rust and get no where. no need to remove bulk of rust or 99% before you use a finer stone.
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if sole plates were blanchard ground you normally can still see grind marks after. basically stone is to get rid of rust or anything sticking up. normally a mill table is not that bad but i have seen large fixtures in storage very rusty before quite often. obviously got to clean rust off
 

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For very rusty old angle plates or something that has been stored outside when it shouldn't have been I always used a scraper (not the precision kind - the remove paint kind) to quickly remove the bulk of the rust. Then back to the 400 grit "puck" with mineral spirits. As long as there is some semblance of the original surface left (i.e. not rusted to the point that the entire surface is pitted away) this works very quickly and quite well.
 
I see a number of old timers stone their mill table and or mill vise jaws before starting a project. What type stone and what grit are they using in order not to damage the table over time? Also, what type of cleaner would one use to clean the table of all the old solidified cutting oil before stoning? Any part numbers would help. Thanks!

Norton Abrasives - St. Gobain
Norton 614636855653 IB8 1-by-2-by-8-Inch Fine/Coarse India Combination Oilstone, Red
Amazon.com: Norton 614636855653 IB8 1-by-2-by-8-Inch Fine/Coarse India Combination Oilstone, Red: Industrial & Scientific
Grit type: fine, coarse
$20

Atoplee 6pcs Grit 3000# Ruby Sharpening Grindstone Whetstone Graver Sharpening Tool 6 Shapes [Square/Triangle/Semicircle/Cylindrical/Edge/Rectangle]
Atoplee 6pcs Grit 3# Ruby Sharpening Grindstone Whetstone Graver Sharpening Tool 6 Shapes [Square/Triangle/Semicircle/Cylindrical/Edge/Rectangle] - - Amazon.com
$33.69
 
For very rusty old angle plates or something that has been stored outside when it shouldn't have been I always used a scraper (not the precision kind - the remove paint kind) to quickly remove the bulk of the rust. Then back to the 400 grit "puck" with mineral spirits. As long as there is some semblance of the original surface left (i.e. not rusted to the point that the entire surface is pitted away) this works very quickly and quite well.

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roughing or rubbing stones the extra coarse ones also remove any concrete grout drips that might have got on 1.5" thick steel floor level sole plates that are grouted to hold machines weighing tons.
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if it sticks up the coarse stones are made to remove it fast be it rust, concrete, a dent/ding
 

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