Thread: lapping problems

Have norton stone kit and a chinese 12k. Even though the pencil lines are removed during lapping, done several times on each stone, the stones are not perfectly flat. Using the lapping stone which came with the norton kit but that is not perfectly flat either. Other lapping mediums or suggestions would be appreciated.

Originally Posted by shortmoneyshave

Have norton stone kit and a chinese 12k. Even though the pencil lines are removed during lapping, done several times on each stone, the stones are not perfectly flat. Using the lapping stone which came with the norton kit but that is not perfectly flat either. Other lapping mediums or suggestions would be appreciated.

Try the DMT 325. I got it from SRD (Straight Razor Designs) and it did a wonderful job on my Naniwa 1K, 5K, 8K and 12K.

-Robert

When lapping your 12k try using a ball point pen to put your grid lines on with. I did the same thing with a pencil and discovered that as soon as you work up a slurry the pencil lines will come right off even if you are not against the lapping stone. After I drew the grid on with a pen it took me about 2 hours to actually get the 12k stone flat.

If you're using a soft pencil the lines will rub off in the slurry right away. Pen seems ok, but I have never used it so I wouldn't know. The DMT 325 is a good lapping stone.

IME lapping on a 325 or a 120 DMT in the kitchen sink with the water gently washing the swarf away is a good method to avoid a build up of slurry that will give you false readings on your grid or cause stiction. YMMV.

Originally Posted by JimmyHAD

IME lapping on a 325 or a 120 DMT in the kitchen sink with the water gently washing the swarf away is a good method to avoid a build up of slurry that will give you false readings on your grid or cause stiction. YMMV.

Right! I don't know how I forgot to mention the running water. This should definitely help with the slurry rubbing the pencil too soon.

shortmoneyshave,

I used all sorts of methods for hone flattening until I finally gave in and got a DMT 325 continuous diamond plate.

Flattening the hones is now so much easier, quicker and cleaner than before

Highly recommended

Have fun !

best regards

Russ

+1 for the 325 DMT. Thats a great stone, very useful for lapping, and you can also use it for major edge repair if you need to.

Lap your Norton on some 220 wet/dry sand paper. Rotate the Norton lap around several times through the process. When lapping you hones also rotate the hone around from time to time and also the lap. If your Norton lap is flat within reason your results on the hones should be just as good. Rotating them while lapping will improve the results. Flat is a relative term. DMT's may give better flatness if rinsed while lapping. With the Norton, I don't rinse very often and allow the slurry built up on the lap to assist in the lapping process. Rinse when the groves in the lap are close to full with slurry. That works best for me.

I picked up some 3M wet/dry grit sandpaper and a 80 grit emery sheet. Lapped the nortons on 80,220,+320, did a great job of flattening. The chinese 12k will need a little more work. After a couple of hours of lapping stones, I put it down for the day. Thanks for all the helpful advice.