What Shapton DGLP Confirmed!

I finally finished off my 10 stone set of Shapton's with the 220, 500, 1k, 30k and also the Diamond Glass Lapping Plate (DGLP) over the last month or so. Today I decided to lap the new ones and clean and chamfer all of them. I started with the new 500 and it lapped in just a few minutes and was barely off from being already flat. I thought how lucky, because all my stones, Shapton, Naniwa, Norton, coticules, PHIG, WHIG, etc. have always been high in the middle and required a fair amount of lapping with the DMT325/DMT8C. I've used the same DMT for all of my lapping over the past 6 or 7 months and its been a good system, maybe? Next I lapped the new 1k and it needed even less lapping with the DGLP than the 500. Both of these stones had a pencil grid. I was going to only clean/light lap the remaining stones since all had been lapped with the DMT325 and had only been used on one razor since lapping. Instead I decided to pencil grid the 2k and lap it with the DGLP (which is rated to within 5 microns of flatness) just to see. It was immediately obvious that it was now low in the middle and high on the ends. It took a fair amount of lapping to flatten it. Accident? Put a grid on the 3k with the same result and so on 4, 6, 8, 16, and 30k all were low in the middle and high on the ends and had been lapped with the DMT. I had kind of checked the DMT before, but not really close because I really thought it was true. I wish I still had my milling machine so I could level the DMT on the table and chuck up a feeler gauge, but of course I sold it a few years ago. So not having a way to really gauge it I laid several of the Shaptons that I had just lapped on the DGLP on the DMT and each-very slightly-rocked from end to end. I can only guess, but I would say the middle of the DMT is off by several thousandths of an inch. Anyway, if you're using a DMT and find all of your new stones are high in the middle, I'd check the DMT first. I'm not knocking the DMT's I've recommended them many times, but I guess now and then a black sheep can always get out of the pen. :confused: Now I've got to re-lap all the other stones!! :boohoo:

Regards,

Howard

I doubt the "flatness" you had in the past hurt anything...don't be mislead that you have to have your stones flat to the millionth of an inch. They need to be flat, but don't get "lap-happy" and rinse your stones down the sink...

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Originally Posted by shooter74743

I doubt the "flatness" you had in the past hurt anything...don't be mislead that you have to have your stones flat to the millionth of an inch. They need to be flat, but don't get "lap-happy" and rinse your stones down the sink...

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Glad you brought that up, I'd intended to add a comment along those lines, but the wife interrupted me so many times I couldn't keep a train of thought going. I agree, but it sure is nice to have one flat as possible to cut down on the original lapping.

Well Howard?

If you used any of those out of square stones on the razors you honed for me, it sure doesn't show in the final product. ;)

NO complaints on this end. :)

Willie

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Originally Posted by Wullie

Well Howard?

If you used any of those out of square stones on the razors you honed for me, it sure doesn't show in the final product. ;)

NO complaints on this end. :)

Willie

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Yeah, I don't think it affected the honing, but it does play havoc with lapping. If you use just a slightly different length stroke or figure eight on subsequent lappings you think your stone has done something weird between lappings because it doesn't remove the grid evenly like it did previously.

Glad those are still working for you!!

Howard

Actually, if you just take off the metal straightedge of a decent tri-square, and lay accross your DMT leveling plate with a strong light behind it, it should show you very quickly is you are off in "Flatness" to any degree that would make a difference in the quality of you finished honing, That's what I"ve found, YMMV!

You're right, but when I sold the shop machines and welders, etc. the small tools and gauges, straight edges and all went too. Anything left was packed for a move and now I could't find them on a bet. Besides, working in thousandths makes one, well, anal. You just have to know exactly how far something is off. LOL. Thanks though!

Best Regards,

Howard