eKretz said:Thank you, this is very helpful. I did see an improvement when I started putting my finger on the center of the part. I can't decide yet if figure 8, straight lines or small circles are better for me, I'm trying all of them at different times. However, I'd prefer not to wear my laps in the middle so figure 8s are probably the least favorable.Want more information on China Lapping Machine? Feel free to contact us.
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Conrad Hoffman said: Click to expand...
Nobby said: Click to expand...I didn't know. It is interesting. I might make my own little bench top lapping machine similar to what Stahli makes.
Nobby said: Click to expand...Thank you :-) I've since managed to get it a tiny bit better. It is still near a quarter light band, but rather than a dome-like shape it is flatter in the middle which mattered to me.
Nobby said:That's on my mind all the time when lapping :-) but with the abrasive embedded in the lap this is less of a problem.Contact us to discuss your requirements of Valve Lapping Machine Price. Our experienced sales team can help you identify the options that best suit your needs.
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Nobby said: Click to expand...I would be very interested in seeing some sort of a chart (if it exists) what oil viscosity with which abrasive grain size. However this information is very hard to come by. Most lapping oil manufacturers don't even publicise their viscosity numbers (maybe they tell their customers, but not the public). One that does listed one if their oils as iso 4. This is very thin indeed.
Nobby said: Click to expand...Definitely :-)
Thank you, this is very helpful. I did see an improvement when I started putting my finger on the center of the part. I can't decide yet if figure 8, straight lines or small circles are better for me, I'm trying all of them at different times. However, I'd prefer not to wear my laps in the middle so figure 8s are probably the least favorable.(multiple posts mention it, so I haven't quoted a specific one). Can anyone say what are actual advantages on using cast iron in manual lapping plates for hardened steel? I have read the same old text ls where they say: "steel works fine, cast iron is best", but they don't actually say why... With my limited experience I can only think (other than more even/predictable bahavior during changing temperatures) about cast iron being better because it's harder to "ding" it. Having a number of them I've already dinged my mild steel laps a few times. Every time I had to stone the dings with the precision ground flat stone, then lap it a little to ensure it doesn't protrude even a little bit. It can really annoy you, having to do that when you're trying to get a part done.Anyway, I've found a supplier locally that will sell me grey cast iron disks at a price of about 7eur per kilo(that's tool steel prices around here BTW). I might order a few 4in ones in future just to see for myself the difference.I like that method (rolling in the abrasive into the lap with a roller). I use a cheap ball bearing (roughly 1.5'' OD, half inch wide) with a piece of stainless tube for a handle. It is important to clean all the loose abrasive afterwards to only leave stuff embedded in the lap. This works not just with diamond, but with silicon carbide paste (probably alox too). It can be used dry for a bit too.I like this method, because it makes the plate wear a lot less and the type of finish is different. (as mentioned before free abrasive vs embedded). Free abrasive results most often in matt finish, embedded is shiny, mirror like.I didn't know. It is interesting. I might make my own little bench top lapping machine similar to what Stahli makes.Thank you :-) I've since managed to get it a tiny bit better. It is still near a quarter light band, but rather than a dome-like shape it is flatter in the middle which mattered to me.That's on my mind all the time when lapping :-) but with the abrasive embedded in the lap this is less of a problem.I would be very interested in seeing some sort of a chart (if it exists) what oil viscosity with which abrasive grain size. However this information is very hard to come by. Most lapping oil manufacturers don't even publicise their viscosity numbers (maybe they tell their customers, but not the public). One that does listed one if their oils as iso 4. This is very thin indeed.Definitely :-). In one of unrelated Robin Renzetti's videos(about sandpaper "lapping" on an old surface plate) he mentioned "you can't get flat parts on concave lapping plate, but you can on convex plate so it's better to wear your plates convex". Two of my laps were very slightly concave. When I changed them to slightly convex (about half a micron) I got much better results. It is also possible I've had more practice by then which contributed, but anyone making their own laps I'd definitely say to have your plates slightly convex rather than concave.
... While you are at this stage with everything apart take a moment to remove those razor sharp edges with a fine mill file or india oil stone - don't get carried away with large radiuses, just break the sharp edge so it can't cut you or someone else.This should clear up some of the confusion and common mistakes made lapping ways.If you decide to lap your ways, you are responsible for the results. No one at CNC Zone including myself, the site owner and site provider are responsible for the results.Mike
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