Help a vernier spaz out please

Fletch Helical

Fletch Helical

Joined
Sep 29, 2009
Messages
1,614
Some of you remember I made a very nice score on a Mitutoyo height gauge a little while back. I searched a bit online and figured out how to read a vernier caliper in "mm". For whatever reason I think I'm spazzing out on trying to use my height gauge for the first time. In theory it should read about the same but for whatever reason I'm having a brain fart I think.

It could be the fact that it's late, it could be the Jack Daniels night cap, or it could just be I don't know how to actually read one of these things as well as I think I do.

This is off a piece of 5/32 stock, which according to fairly basic math should equal 0.15625.

I know reading a vernier on a caliper you take the reading at where the vernier scale is at zero and then find where the lines line up further down the scale. Why am I coming up with something like .16822.... Tell a spaz what exactly I'm looking at here please :o.. Naturally after you've finished laughing.

vernier.jpg
 
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If your flat bar is not precision ground it wouldn't surprise me if it is .01197 thicker than 5/32. Try reading the thickness with calipers.
 
Also, any dirt, or grinding dust beneath the knife, height guage, or the point on the height guage will throw it off ten or so mils easily.
 
Its probably the camera angle, but if you read at the 0 mark, it looks to be just a little less than .175". If you read at the vernier match point (25), it actually reads .175" even. You have to get your eyeball directly over the reading point. How did you get numbers in the ten thousanth and hundred thousanth column. Your gauge only reads to the nearest thousanth of an inch.
 
tiguy7 said:
How did you get numbers in the ten thousanth and hundred thousanth column. Your gauge only reads to the nearest thousanth of an inch.
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This is what lack of sleep and a bit of JD can do to you kids :o. I was adding places that weren't even there :p

I double checked it again this morning and from what I'm gathering It's coming in at .172 the match point to me looks like it's at 22. So I'm going to set it for center at .086 to mark my line correct?

Also since this is my first time marking a center line when I grind I might as well attempt to mark grind lines on either side to grind to.... What is the usual distance you guys go to either side of center?

I'm attempting to go totally mathematically on this one. I found a grind angle chart which lists stock thickness to grind height to tell you what angle to grind at. So I want to see if I'm able to use the grind lines, plus the grind chart PLUS the bubble jig to see if everything matches up to (near) perfect as my limited skills allow..... Hopefully.
 
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Los Angeles said:
Could you share that grind angle chart? I've always been curious about that.
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Post #4 has a site to calculate it Post 9 has the PDF chart to download both are here. Although it doesn't have a listing for 5/32 I figure ballparking it isn't all that tough.

This post shows how you can run the formula but I was never very good with math formulas... So I'm just using the cheat sheet :p
 
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