porch paint on lathe compound, accuracy for QCXTP

porch paint on lathe compound, accuracy for QCTP

I bought a used compund slide for my Harrison M300 which came with a Jerry rigged USA one. It looked good on ebay and it is in good shape except I did not realize they painted it with gray paint over all the machined top surfaces. Lucky not the bottom or inside the tee slot.
My question is do I need to remove the paint from the top where the QCTP will bear on it. Seems like the paint might be soft and allow the toolpost to rock. Do you think this will be a problem?
I also will use the painted side to measure from to set the compound angle but I do not think the paint will effect that enough to matter.
Bil lD

PS I have to pry out the gits oiler so I can get the paint out of it. Many folks suggest using a flip top cup oiler there instead to keep out chips.

without knowing how thick the paint is, hard to say if it would be of any disadvantage, or advantage actually. a number of people put paper under the tool post to increase the friction coefficient. the paint being somewhat squishy may be of some advantage if the surface isn't flat and you can't take the time to scrape and or grind both surfaces flat or slightly concave so the clamp load is on the perimeter.. i can't imagine it would be too thick to reduce the rigidity within reason.

however i would scrape it all off to verify they didn't paint it to hide a crack.

Bill D said:

do I need to remove the paint from the top

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Yes........

if thick paint put paint remover on it and in 10 minutes scrape the goo off

I question why it was painted in the first place, those compounds are ground on all sides and make for a handy surface for my magnetic sine bar on some set-ups, etc.. It could be the owner painted it to keep it rust free until he decided to use it or maybe it was on there to hide a repair? Don't know the answer but I would strip it to bare iron and use it as is if it were mine. Those ball and spring oilers are somewhat iffy but a oily shop rag is good for cleaning swarf out of them, if you hate them enough just remove and thread the hole for a shop made plug and be done with them.
Dan

my wife had so many paint drips painting bathroom ceiling she painted some of the wall tile rather than clean the drips off. i ended up using paint remover the thick stuff like paste. you apply and wait 10 minutes and you scrape off the soft goo.
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a lot of paint jobs like that people paint rather too much than remove drips or cut in neatly where paint surfaces suppose to end neatly

On the gits question, I don't think I've ever had a problem with chips getting past a ball-spring oiler, although it isn't clear how I'd know it if they did. I just give the oilers a wipe & a brush before filling or replacing.

-Marty-

Why does anyone even have to ask? You simply don't mount accurate devices on painted surfaces. Paper is fairly uniform thickness from one point to one a few inches away. Paint isn't.

Re Gits oilers, don't try to pry it out. You will only make a mess. Open up whatever you have to and use a rod a little smaller than the hole to push it out.

Bill

9100 said:

Why does anyone even have to ask? You simply don't mount accurate devices on painted surfaces. Paper is fairly uniform thickness from one point to one a few inches away. Paint isn't.

Re Gits oilers, don't try to pry it out. You will only make a mess. Open up whatever you have to and use a rod a little smaller than the hole to push it out.

Bill

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had 100 year old machine and needed to mount part subassembly on it and paint was easily 0.1" thick. took parts off (about 3 foot long) to get paint removed and nickel plated.
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paint was lead based and part had old cadmium plating on it. to get both removed per OSHA and EPA rules it cost a hugh amount of money and engineer told me do not ever do that again. but if you need to mount parts securely and accurately and be stable how can you do that on surface with 0.1" thick paint of dozens of layers on it.
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you cannot even sand blast lead paint without the sand being considered a lead hazard. literally you got guys in tyvek paper suits and masks using chemical goo paint remover to remove paint and limit dust which needs to be collected. not allowed to get lead paint dust all over the place contaminating everything.
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just saying industrial rules from OSHA and EPA might say what you are allowed to do with a painted surface