Looking to make some scales, basic questions

[KnifeManatee]

Hi all,

As is obvious, I'm newer on this forum -- I looked through the stickied threads page and couldn't find any relevant information on this, as well as scores of other sites and technical websites but failed to find the information on it.

I've a few knives I'd like to make scales for as well as perhaps outside of doing it just to learn the process, going through and perhaps selling them once I get better at it.

1. The primary problem I'm running into is the technical side of things, primarily with screws, taps and dies, and thus bit sizes to drill with and how to determine the screw size from a para 3 to a kershaw leek, and so on. I've never been to keen on figuring that out. Would calipers and a chart be the quickest solution? I'd think the screws would simply be too small.

2. I'm also looking for some clear epoxy/resin recommendations, I made some micarta and it went relatively well but the epoxy was brown in nature so obviously that discolored the canvas material when done.

 

[FredyCro]

Some pics of the knifes would be helpful. There are different ways to mount a scale. Straight pins (with or without peening) , corby bolts, loveless bolts, screws with a threaded tube. All include a good quality epoxy.

Homemade mycarta (mycarta stand for diy micarta) is harder to finish and doesn't reach the quality of the real stuff. It is probably also not cheaper then just buying the real stuff. Look for a clear 2k UV-resistant epoxy, most of them harden completely clear. Fiberglass epoxy produces better results for mycarta according to my research but has a yellowish hue.

 

[C_Claycomb]

To answer your first question about screws.
US made knives tend to have Imperial size screws, which in folding knives tend to be 2-56UNC, 4-40UNC, maybe 6-32UNC although that is somewhat more unusual. Japanese and Taiwanese made knives tend to have Metric size screws. M2, M2.5, M3 and maybe M4. To figure out what you have you really want to work from the screw. Measuring threaded holes this size, accurately, isn't the easiest way to work. Better to have sample screws and try them! To work from the screw, you need a set of Vernier callipers, or a micrometer so that you can measure the major diameter to 0,00mm or 0.000inch. I would recommend the Vernier Callipers since they can be used for more things than a micrometer (inner and outer diameters, depths, distances and offsets), although at some point, if you carry on, you will probably want both.

To identify the screws, or to choose tapping drill sizes or standard clearance drills, you just need to use a reference table. I have one that came from MSC Direct, but there are plenty on-line that you could print or copy out for easy reference in your workshop. Simpler version is that screws work from diameter and pitch, the distance per turn of thread for metric or turns per inch. You can often get an ID just from the diameter. With experience you can learn the difference between say an M2 and a 2-56UNC at a glance. When you are not so sure, you can measure the length of thread, count the number of turns and divide or multiply as needed to get the length per turn or turns per inch. If the number you get doesn't fit one standard, you try the other.

Most times you are just making clearance holes in scales since the threaded parts are the liners, or metal inserts fitted into the scales. So it could be argued you don't really need to know the screw size, you just need to know the dimensions of the screw, and buy drill bits that suit. As an example, I have bought a number of filister counterbore tools from a couple of US knife supply companies, and bought filister head screws from same companies, only to find that the counter bores cut are too tight for the screw heads. So much for working by size rather than dimensions.


Regarding epoxy, no direct experience myself. Have you searched much? I might look at some of the casting resins that wood workers are using. Low viscocity, clear, hard enough to be machined, sanded and polished.

https://www.bladeforums.com/threads/what-resin-to-use-for-making-micarta.1612563/
https://www.bladeforums.com/threads/different-resin-epoxy-home-made-for-micarta.1512882/
https://www.bladeforums.com/threads/micarta-resin-epoxy.447464/
https://www.bladeforums.com/threads/making-micarta-that-easy.1246816/

 

[KnifeManatee]

To answer your first question about screws.
US made knives tend to have Imperial size screws, which in folding knives tend to be 2-56UNC, 4-40UNC, maybe 6-32UNC although that is somewhat more unusual. Japanese and Taiwanese made knives tend to have Metric size screws. M2, M2.5, M3 and maybe M4. To figure out what you have you really want to work from the screw. Measuring threaded holes this size, accurately, isn't the easiest way to work. Better to have sample screws and try them! To work from the screw, you need a set of Vernier callipers, or a micrometer so that you can measure the major diameter to 0,00mm or 0.000inch. I would recommend the Vernier Callipers since they can be used for more things than a micrometer (inner and outer diameters, depths, distances and offsets), although at some point, if you carry on, you will probably want both.

To identify the screws, or to choose tapping drill sizes or standard clearance drills, you just need to use a reference table. I have one that came from MSC Direct, but there are plenty on-line that you could print or copy out for easy reference in your workshop. Simpler version is that screws work from diameter and pitch, the distance per turn of thread for metric or turns per inch. You can often get an ID just from the diameter. With experience you can learn the difference between say an M2 and a 2-56UNC at a glance. When you are not so sure, you can measure the length of thread, count the number of turns and divide or multiply as needed to get the length per turn or turns per inch. If the number you get doesn't fit one standard, you try the other.

Most times you are just making clearance holes in scales since the threaded parts are the liners, or metal inserts fitted into the scales. So it could be argued you don't really need to know the screw size, you just need to know the dimensions of the screw, and buy drill bits that suit. As an example, I have bought a number of filister counterbore tools from a couple of US knife supply companies, and bought filister head screws from same companies, only to find that the counter bores cut are too tight for the screw heads. So much for working by size rather than dimensions.


Regarding epoxy, no direct experience myself. Have you searched much? I might look at some of the casting resins that wood workers are using. Low viscocity, clear, hard enough to be machined, sanded and polished.

https://www.bladeforums.com/threads/what-resin-to-use-for-making-micarta.1612563/
https://www.bladeforums.com/threads/different-resin-epoxy-home-made-for-micarta.1512882/
https://www.bladeforums.com/threads/micarta-resin-epoxy.447464/
https://www.bladeforums.com/threads/making-micarta-that-easy.1246816/

Thank you, I'll definitely look into that and do some more research