Silly Question -- Mill Scale?

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diverdale

Well-Known Member
Total new guy question. Do you guys sand off the mill scale before getting started on your blades (stock removal)?
 
For my stock removal knives I do. I like to have 90% of my ricasso area sanded before HT so I find it easier to sand the profiled blank to 400-600 grit early. I do all of that on my grinder. It also help me to know I am starting with relatively flat blanks too.
 
diverdale said:
Total new guy question. Do you guys sand off the mill scale before getting started on your blades (stock removal)?
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From your question Im not sure what your process steps are. But here is mine.
I do most of my grinding pre-heat treat. When I have the blade ready I heat treat and quench. I remove scale prior to tempering with a combination of grinder and hand sanding. Then it’s final grinding - fit and finish.
Hope this helps.
 
diverdale said:
Total new guy question. Do you guys sand off the mill scale before getting started on your blades (stock removal)?
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opaul said:
I'm not sure what your process steps are.
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I'm also a bit confused. As soon as you start grinding, the mill scale will be gone. Sometimes you can use the mill scale to scratch your layout lines in, but this doesn't always work, especially if your scribe isn't extremely sharp. And sometimes a chunk of scale will pop off (but you can just go over the line again in that spot). There are a lot of folks who will grind off the scale before applying layout fluid to scribe the layout lines in. This works all the time and some folks find it faster to do this than fighting the mill scale.
 
billyO said:
I'm also a bit confused. As soon as you start grinding, the mill scale will be gone. Sometimes you can use the mill scale to scratch your layout lines in, but this doesn't always work, especially if your scribe isn't extremely sharp. And sometimes a chunk of scale will pop off (but you can just go over the line again in that spot). There are a lot of folks who will grind off the scale before applying layout fluid to scribe the layout lines in. This works all the time and some folks find it faster to do this than fighting the mill scale.
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I read the initial post incorrectly. I was thinking heat treat scale, thus my answer.
Yes. I do remove the mill scale and flatten/true the blade before stock removal.
 
I am obviously a forged steel guy but I've done enough testing work for myself and clients to make some observations. Removing iron oxide scale will save on belts, and also be aware that where there is oxide scale, there most likely be decarb on some level. That hot rolled bar stock with the rounded and bulged edges can have a significant amount of decarb. Clean and uniform steel surfaces heat treat more uniformly and will offer less opportunities for distortion.
 
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Thanks guys ... I've removed the scale before getting started as well .. just wondering if I was wasting time/energy in doing so.
 
Any more Before I even grind the bevels i lay the whole blade on the Platten (scratches running From tip to butt.) and go up to whatever grit I am going to stop grinding bevels at. I find this gives me better results personally.
 
I always grind off mill scale. Another reason to do so it that the bar stock you get is never 100% flat, and you always want to have that flat foundation to start to make sure you are in proportion. I do this with my disc grinder but you could also use your platen lengthwise
 
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