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A guy in a Detroit shop told me to always hand-scrape a new vise before trusting it

I was setting up a new machine at a job in Pontiac last year and this old timer named Carl saw me just bolting down the vise. He walked over, tapped it with his knuckle, and said 'You'll get a tenth out of it if you scrape the base first.' He spent twenty minutes showing me how with a piece of granite and a sharpie. Anyone else still do this for critical work?
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3 Comments
pat_perry
pat_perry1mo agoMost Upvoted
Oh, absolutely. That old timer knew his stuff. I had a similar thing happen with a surface plate that just would not sit right. A bit of careful scraping with a hand scraper and some Prussian blue made all the difference. It's a slow job, but for getting things truly flat and locked down, you can't beat it. I still do it for any setup where half a thou matters.
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ellis.nina
ellis.nina1mo ago
Truly flat" sounds like overkill for most jobs. Modern vises come pretty good from the factory and I've never had one fail me. That whole process seems like a solution looking for a problem.
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paul_lane80
paul_lane8012d agoMost Upvoted
Have you ever tried to hold something really thin or delicate? Factory vises are fine for rough work, but they often rock slightly. That tiny bit of movement can ruin a finish or throw off a precise measurement. Taking the time to flatten the jaws makes sure everything is solid and square. It's not overkill if you need things to be right, not just close.
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