What are the Mechanical Properties required for a good Lap ?

[m82bd586a]

Hello Members

What are the Mechanical Properties required for a good Lap ?

I am used to reading a specification and having the task that has to be performed and then choosing a material for the task.

I am very new to this Faceting Game, however I notice that there are many types of materials that are used for making laps.

I understang that a cutting lap has the cutting material impregnated into the surface of say a copper lap.

But what about all these other materials eg Tin, Type Metal, 60/40 Solder, Steel, Cast Iron, Perspex, and the list goes on.

Which material is the best for the application.

Advice please.

Kind Regards

Ian ORRELL

[Alan Balmer]

Very big question. The best lap material depends on your technique, what material you’re cutting, what you are using as a cutting/polishing media, and what the operation is. About the only purely mechanical property is that it be flat with parallel faces.

If you have specific questions, you will get specific answers, usually several different ones. We don’t always agree on the best way to do things. 🙂

Otherwise, research. Search the message boards at Gemology Online, or the old USFG Faceter’s List on Yahoo. You’ll find information on commercial sites, e.g. http://gearloose.co/product-charts/ (though the charts there are not updated with the latest laps.)

If you’re not already a member, join USFG. For $18, you get access to many years of information and opinion in the newsletter archives.

[Tom Mitchell]

Ian,

Do I assume correctly that you want to make your own laps or are you looking to purchase laps and you are looking for advice on what to purchase?

Tom Mitchell

[m82bd586a]

Hello Tom

You got it right first go.

I have already made three [3] laps.

1. Copper top on Casi Iron

2. Pewter [ royal Selangor Pewter Sn 97%, Cu 2.3 % Sb 0.7%]

3. Zinc

I am not looking to buy [ a dirty three letter word] LAPS. as I have plenty of materials to make my own.

I just haven’t been able to source the Mechanical Properties required.

Kind Regards

Ian O

[m82bd586a]

Thank you to Tom and Alan for your answers.

Kind Regards

Ian Orrell

[gemmakermz]

hey friend, you want to facet? ok making laps that will only end up causing you time and troubles is not worth it. go to ebay and buy the cheap china made laps for cutting/grinding. what size do you need? 6″ or 8″ what machine are you going to use? i’m 78 and been faceting and teaching same for 53 yrs. i’ve use most all machines and laps. the china laps (plated/metal bonded) are cheap/ affordable and very good functionally. if you want to make a lap make a good tin lap for polishing as the ones out there are expensive. if you dont have a machine make that, i’m doing that now for my club members. there’s a new machine from china on ebay item # 183491495656 that is quite affordable. if you need more insight email me at gemmakermz@cs.com

[Dennis Anderson in sunny Southern California]

Ian Orrell, as just stated, making you’re own laps is OK as long as you are willing to live with our own results and are going to experiment with the alloys to get what you want. The mechanical specs are pretty simple, make the lap as sturdy as you feel is needed to avoid bending the lap too much (about 2 or less 1/00 ths of a degree) when light pressure is put on the lap while you are cutting. The rest is all your own to learn what you like. Note the bending is subject to the lap and the machine that you using it on as you cut.

Dennis Anderson, In sunny Southern California.

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