How to Braze Carbide

[rwm]

I would like to make a mini carbide boring bar. My plan is to braze some 3mm carbide rod into a hole in a larger piece of steel. I have never brazed carbide. What type of braze rod is appropriate? Do I need any special flux? Have you tried this and if so do you have any tips?

Robert

 

[4ssss]

You use silver solder for carbide brazing

 

[4ssss]

If I read your post right, you can also shrink fit that carbide into the steel and avoid any brazing.

 

[rwm]

If I read your post right, you can also shrink fit that carbide into the steel and avoid any brazing.

Theoretically I could do that but the carbide is only 3mm diameter and I don't have the ability to make an accurate hole that is 3mm minus .002"
I have some 56% Ag solder as well as white and black flux.
Robert

 

[bill70j]

Do I need any special flux? Have you tried this and if so do you have any tips?

Robert

Robert:

I used Hobart brazing flux and a 1/8" bare bronze rod to make a LH boring bar from a scrap TPG insert and a DIY bar. Worked great.

Here is a YouTuber showing the process start to finish. I followed roughly the same procedure, except used oxy acetylene. I think he used MAPP gas. He starts the brazing at about 9:30 in the video.

HTH, Bill

 

[whitmore]

Theoretically I could do that but the carbide is only 3mm diameter and I don't have the ability to make an accurate hole that is 3mm minus .002"

Steel expansion of a 3mm hole with red heat is only 12 parts per million per Kelvin; at yellow-red heat, circa 1300 K, it's really TOO hot,
and the hole only gets to 1.4 mils bigger. Maybe you could grind the carbide to a taper, and taper-ream a socket for it,
though. I see 3mm taper pin reamers are available on eBay.

 

[NortonDommi]

I've found tinning the carbide with cast Iron flux and Tobin Bronze first makes it very easy to set with some Easy Flo.