Brazing O1 tool steel

I want to grind a form tool from O1 tool steel. I have a piece 1/8” x 1 1/2”. I need to braze it to a handle of some sort so it can be used on a wood lathe.
So the big question is how or in what order do I heat treat it?
If I harden and temper what effect will the brazing have?
Almost seems like a catch 22!

Thanks

What I have done in the past is pocket tool steel in the shank so it is well supported and then used TIX jewelers solder. It is relatively high strength and low eutectic temp material.

Alternately you use a long piece of O1, put the working end in chill blocks, or wet sand and solder on the distal end with something like BAg8 silver solder and black flux and be quick about it with a soft slightly reducing oxy-fuel mix.

And the secret to TIX is absolutely clean, oxide free close fitting joints.

True brazing works better with HSS than O1, because brazing temperatures (over 800F, BAg-7 at 1150F) will take the temper right out of O1, and if you reheat the O1 tip to requench (1400-1500F), you'll probably melt the braze. Seems like you were already aware of that.

A strong solder (like TIX mentioned above) to hold the tip in place while a mechanical pocket resists the cutting forces will retain much more of the tip's hardness. You could also bolt your 01 form tool to the shank, as an alternative to brazing.

You might make your form tool from hardened HSS instead of O1. If you're careful with the brazing, you won't draw much of the temper. And the result would probably be more abrasion resistant than O1.

could you redesign the tool to a mechanical connection rather than a brazed connection? you aren't
curling blue chips on a pacemaker here. depending on the design, a pin and socket w/ jb-weld or set screws
might be an option.

Silver brazing can be accomplished without damaging hardened areas if:

1) There is enough space between the area to be brazed and the hardened area
2) A heat sink is used. This can be as simple as a couple pieces of 1/2" square stock clamped to the both sides of the part just behind the hardened area.
3) brazing is done with the area to be brazed oriented on top.
4) Heat is aimed and controlled.

There were several times while brazing PCD tipped multi flute endmills or milling cutters where we used these techniques. Of course your example may not be applicable if there is not enough space behind the hardened area. Also it will depend on the thickness of the O1 stock as well. Hope this helps.

Best Regards,
Bob

Rather than brazing is not the above tnmgcarbide mechanical attachment just as fast, easier, and less worry?
Don't they hold inserts into holders with tiny screws or a simple clamp?
Yes one could braze O-1 to a shank without killing the hardness but you had better have a lot of experience with heat control, color temps and a way to suck the heat from what will be the cutting edge.
A cooled heat sink in the right place up top can prevent the draw at the cutting edge.
Bob

+1 on Carbide Bob's response. Also to add to my previous response that while it is possible, it would be reserved to an expert at silver brazing. If possible, a mechanical solution would be best.

Best Regards,
Bob

tnmgcarbide....great minds thinks alike. I did just that. Turned up a nice handle out of Ash. Used a piece of 1/2" rod turned down a shoulder to 3/8" dia. to screw into an aluminium block that's 1/2" x 2" x 2" with a 1/8" slot to hold the form tool with a coupld of grub screws. This came to me the other day. I filed out a profile and gave it a try without heat treating just to see how it would work. I just used a pair of Vice Grips and it turned the hard Maple perfect.

Then It hit me that If I can hold it with Vice Grips why not just make up a tool holder and call it job done. Plus the added bonus that I can try out a tool before heat treating to make sure I like what it's doing.

I'll post a pic of it when finished.

Heretic here. Going back to original dilemma .. why not weld? Some 50 years ago, doing a bit of stick welding with a buzz box, needed a chipping hammer to dislodge slag. Weekend, days of no REAL shops open here. Had a piece of O1 about 3 1/2" long x 1" wide x 5/16" thick. Hacksawed & filed to 'blade' one end, 60 degree 'point' t'other. WELDED a 3/8" dia mild steel shaft with 6013 I happened to be using, old valve spring for a hand grip. Torch hardened the head of the 'hatchet', torch tempered the blade & point individually. Meant to buy the 'proper' tool following week, didn't, still using the improvisation, it having never failed or worn out. These days, knowing better would probably use 'Weldall' as it's called here (think it's 312 stainless) to play safe. Only submitted this to tell how forgiving O1 is, & how amenable to a 'quickie'.

Well here it is so far. Untested at this point. The handle hasn't been pushed all the way on either.