Carbide scribe

Date 09-18-2007 12:45

I have available sources of carbide. I have been successful in putting chunks and pieces of carbide on and in the ends of carbon steel screwdriver handles and rods. I have used unnamed and unknown fluxes and silver brazing materials and would like to stop playing and get it right. The tools I make are low impact except during sharpening. I drill a hole in the end of a 3/8" rod, insert the carbide and braze in place.

I have Harris "0"%, "5"%, "15"% silver. I also have a 1 # spool of Allstate Dynagrip #430 soft silver solder.

My carbide tips don't come off when exposed to grinding during sharpening. By accident got something right.

What is a good brand or type of flux to use with these products?

What kind of grinding wheels work best to sharpen carbide?

Thanks for any help, this area of metal work is a little out of my training area.

Dennis

By Tomwalz (*)

Date 09-18-2007 15:59

Probably what you are doing right is being a good workman. Most problems with carbide brazing are caused by poor surface preparation.

Alloy recommendations are at www.brazealloy.com

For Flux , White flux lets you see what you are doing but Black flux is much more forgiving.

Fro brazing help go to:

http://www.carbideprocessors.com/Brazing/book/index.htm

the free stuff is at the bottom. This is a couple versions old but the basic stuff is still good.

If it is easier you can call emily at 800 346 - 8274 for tech advice and materials. If it gets really technical she'll come wake me up and we can chat.

Tom Walz

P.S. The above covers flux, alloy, cleaning and process. The missing part is carbide surface preparation. Sometimes it works as delivered. If it doesn't just sand or grind the surface until it is a clean gray color. There are surface preparations and you might want to specify your carbide braze treated or similar.

T

By DaveBoyer (*****)

Date 10-04-2007 05:20

For grinding carbide a diamond wheel works best, the other posibility is a silicon carbide wheel. These are green in color. Silicon carbide does not work nearly as well as diamond, but is much cheaper. There are 2 types of diamond wheel on the market, plated and resin bonded. The plated wheels have 1 layer of diamonds held in a nikel plating matrix. The resin bonded wheels have a layer of diamonds usually 1/16" or 1/8" thick. The 100% concentration wheels work the best. A 100 grit diamond wheel cuts fast, but leaves a rather rough finish. 220 grit diamond wheels give a pretty good finish. There is a white abrasive stick used to clean the wheel if it stops cutting eficiently, be sure to have some on hand. These are for use on resin bonded wheels only. In silicon carbide wheels, a 100 or 120 grit wheel works pretty well.