Care and treatment of Laps
I am mainly going to be talking about steel cutting laps. But most of this will apply to all laps in general.
A complaint I hear periodically is that “there is something wrong with my laps…” Usually people think that it is a problem with the laps themselves.
Which certainly can be, and is sometimes true. All lap manufacturers from time to time have some production problems. It just happens… not often, but it does.
But in a lot of cases it is inexperience on the part of the faceter. Particularly new faceters, partly because of being a brand new faceter, bad advice, or mistakes and accidents (like dropping a stone and quill onto the cutting face of the lap) and various other problems.
Of course another reason more beginners have problems with laps is they are usually buying quite a few because they need all of them and just the sheer number of laps they need to start faceting, mean they are likely to get a bad one occasionally.
So here are some basic things to do in the care of your laps…
Always run enough coolant/water. You should not see any waste build on your lap while cutting. If you are not sure more water is better than less. Especially on a coarser lap. Too much water will get you wet, but too little will ruin a lap quicker than about anything else.
Always flush your laps well with water to clean off any cutting residue and let them dry off completely, when you are done cutting.
Always spin dry you laps completely before storing them away.
Always break in new laps gently.
Always keep your stone moving in a sweeping motion across the lap so that you will wear the lap evenly.
Always use use light to moderate hand pressure. Using heavy pressure (a lot of people do) to “cut faster” loads up your lap and pushes the diamonds down into the metal. They will quit cutting if that happens, see “dressing laps” below.
Always use the right grit lap. Do not send a boy to do a man’s job. In other words use a 260 or a 100 grit lap to rough (especially large stones and Quartz) stones not an intermediate lap like a 360 or 600.
Always do most of your cutting on a coarser lap. Cutting on a fine lap wears them out (and is slow). You should use the fine laps for meeting facets and pre-polishing, not cutting off a lot of the rough in shaping.
Never… (If you have done any of the below things, you have damaged your lap…)
Never put your laps away wet, they will rust and moisture over a long period of time can damage the plating.
Never drop,ding, scratch, or damage the cutting face of the lap in any way.
Never cut metal on a lap, like a dop.
Never cut just in one place on a lap. Particularity girdles, you cannot sweep them as much obviously, but adjust the stone and dop so that you are not always cutting in one very narrow spot (the girdle) on the lap. If you cut just a few girdles (particularly with a hard stone) in one spot, even on a new lap you will wear the plating off in no time.
Never dig in the stone on the lap with too much pressure. Gently, use light to moderate pressure. Think about it, a girdle especially, is a very small edge and with pressure it will slice through a lap like butter. The stone is usually a 7 to 9 in hardness the lap is a 4 to 5 depending. You do the math…
Never cut with a lap if you see sparks. If you see sparks you do not have enough coolant running on the lap. The sparks are an indication that you are running hot and are damaging the plating bond of the lap.
Never ever “clean” your lap with a wire brush, scraper, Brillo pad (SOS), sand paper, and so on (yes I have had people do it). All of these things and more will damage and remove the plating from the surface of your lap.
Never run a lap dry and “cut” anything on it dry.
Never “clean” your lap with chemicals or solvents (very mild dish washing soap is OK).
Never “clean” your laps with scrubbing cleaners, like “Comet” . These cleaners have abrasives (grit) in them to help clean. They will damage the plating on a lap quickly.
A few other things:
It is common for a new lap to start out course, and “break in” over time. Typically when a lap is “broken in” it will cut quite a bit finer than it did initially.
Typically the coarser the lap the longer it takes to break in and the tougher it is. It lasts longer.
Typically the fine grit laps are more tender than the coarse laps. They wear faster.
Typically the manufacturers seem to have more problems with the very fine laps. Some of it is just maybe the mechanics of plating with the fine grits. Some of it is that the fine laps are just more tender and cannot take the abuse some people give them (like cleaning them with Brillo pads).
By far the most common problem that people have with laps is they seem to quit cutting.
Note: Like I said before manufacturing problems happen, but are generally not common.
Now assuming that there is NO problem with the manufacturing/plating on the lap. There could be…
Also assuming that the person with the problem lap has not done some thing to damage the lap, like clean it with a solvent or wire brush.
The most likely problem that the lap has is that it needs to be dressed.
Dressing Laps – By far the most common problem that people have with laps is they seem to quit cutting. What basically happens is one of several things.
The laps get “loaded” up with cutting waste and clog. Quartz is pretty famous for doing this, there is something about Quartz that clog’s laps, I am not sure what.
The person using the lap has used too much pressure (or maybe a really large stone) and driven the diamonds down into the lap. Basically the metal of the lap is covering the diamonds and they quit cutting.
Or sometimes the diamonds just seem to become dull and need to be sharpened. I do not know if they really get dull but they sure seem to.
Often the problem is a combination of these things. Of course the lap could be worn out too.
The solution to these problems is to “dress” your lap. By dressing I mean removing the waste clogging your lap and/or some of the metal that is covering your diamonds to re-expose them. Notice that there are two different grades of dressing sticks.
Lap Accessories – Dressing sticks are on this page.
Coarse – for 360 grit laps and coarser
Fine – for 600 grit laps and higher.
Note: Do not use a dressing stick on Nu Bond type laps, or on polish laps, they are strictly for steel cutting laps. Yes they are fine for steel “cap” laps.
It is very important to use dressing stick only when needed and sparingly. They do remove lap surface and over use of dressing sticks will eventually damage a lap, so never use them unless you have to.
Take the correct dressing stick for the grit of lap you are dressing and run it at a moderate speed. Use lots of water, gently apply the stick evenly across the face of the lap once or twice. Flush with water… Try cutting a stone. Re-dress the lap again if needed. That is it really, generally dressing the laps will get them cutting again.
OK, you have done all of that and still have a problem.
Assuming the lap is new it’s time to talk to the manufacturer and/or the dealer you purchased from. Like I said before there are occasionally some manufacturing problems, it does happen. It is too early to tell if manufacturing problems are getting more common because of cutting corners (like cheap labor). I do not know yet, but it maybe happening, manufactures are certainly cutting cost corners and not being very responsive.
Most dealers will try to help their customers. I have heard mixed results from people about manufacturers.
But keep in mind that people do “clean” their laps with SOS pads, wire brushes, solvents and so on which ruins them. There is always two sides to the stories, you may not be hearing all the story. Usually the manufacturer will want to see the lap before making a decision.
On some laps the defects are obviously manufacturing and most of the time a replacement laps is just supplied. Either by the dealer (who later hopefully gets a credit from the manufacturer, it can take a long time, and sometimes not happen) or by the manufacturer.
But here is the rub, on some laps there is not really any way to tell what the problem was/is caused by. It could be a manufacturing problem, or it could be something the customer did.
This is where things get difficult…
It is the gray area that causes all the problems. Usually a dealer will try to give the customer the benefit of the doubt and try to help their customer. I do… most dealers do.
Please remember that if a dealer makes it good to you trying to make the customer (you) happy there is a fairly good chance that the dealer will end up with a total loss on the lap.
Particularly if the lap seems to be abused or maybe just falls into the gray area. Large manufacturers are a lot like insurance companies, any out is fine with them. I have had this problem with almost all manufacturers.
There is very, very little profit in laps (sometimes they are sold at virtually cost), so if the dealer makes a lap good to a customer (being a nice guy) the dealer is losing on the whole deal. If a dealer makes a questionable lap good to you… it is called customer service. Chances are pretty good the manufacturer will not support the dealer’s decision.
Most dealers still do make an honest effort to support their customers.
Here is another article you should read…
I am about the only person I know making these issues public. You may not agree with me but this is how I see things in the business. Time will tell… In the mean time I will do the best I can for my customers.