Question: Steel for multitool chisel and awl

**Elizabeth Greene** · May 23, 2022, 02:22 PM

Howdy. I'm going to be making an awl and chisel for my multi-tool, and I need some steel advice. Both tools will be less than 1.75 inches/50 mm long with a maximum width of < 1/2 inch/13mm.

Would I be completely off the mark if I used HSS Tool steel for these applications? I'm sure it would be fine for the chisel, but I'm less confident for the torsion loads on the awl. I can get a "HSS Steel Square Flat Bar Strip High Speed Steel 2 3 4 5mm x 200mm Lathe Tools" from eBay for super cheap, but I don't know what I don't know. If a kryptonite alloy steel from McMaster would be better, I'm willing to pay more.

If it changes your answer, I'll have to anneal these to drill the pivot hole and the new heat treatment will be done under less than ideal (Torch, oil, oven for tempering) conditions.

**Toolmaker51** · May 24, 2022, 06:42 PM

Speaking about general materials and experimental toolmaking, thin enough HSS for the connection will be troublesome. I'd braze 1095 spring steel to oil or water hard and they both have good machinability.

((edit in)) Tremendous benefit of both Oil and Water hard, probably easiest of all the tool steels to attain hardness desired, not requiring atmospheric furnaces, detailed timing, or sophisticated quench mediums. Darkened shed, pre-armed with known color to attain, and either of the two quench liquids. Drawing back, about the same, knowing what shade straw-to-violet results to monitor.
And they are economical. O1 is very common in flats and rod 'drill rod', a little searching all the way into high graphitic. W2 is often used for collets, cold work punches and locators.

All the auction sites will periodically have material catalogs, find one including tool steels, that even have machinability ratings, recommended applications, heat treat parameters, and most important a 'conversion' or comparison of alike brands. Mine are Earle M. Jorgensen and LaSalle.

**Inner** · May 24, 2022, 08:34 PM

I think HSS from eBay will work great. I've seen them made out of nails, drill bits, and other general scrap. Like Toolmaker51 says, the connection may be the real issue. Here's Linn of Darbin Orvar making a simple one from a nail:

**TheElderBrother** · May 25, 2022, 01:23 AM

I have a heat treating oven if that helps. Make your parts and send them to me. I'll heat treat them and send them back.

**CanBeDone** · May 25, 2022, 03:34 AM

Originally Posted by Elizabeth Greene

Howdy. I'm going to be making an awl and chisel for my multi-tool, and I need some steel advice. Both tools will be less than 1.75 inches/50 mm long with a maximum width of < 1/2 inch/13mm.

Would I be completely off the mark if I used HSS Tool steel for these applications? I'm sure it would be fine for the chisel, but I'm less confident for the torsion loads on the awl. I can get a "HSS Steel Square Flat Bar Strip High Speed Steel 2 3 4 5mm x 200mm Lathe Tools" from eBay for super cheap, but I don't know what I don't know. If a kryptonite alloy steel from McMaster would be better, I'm willing to pay more.

If it changes your answer, I'll have to anneal these to drill the pivot hole and the new heat treatment will be done under less than ideal (Torch, oil, oven for tempering) conditions.

The answer depends on what you mean by "Multitool". Here in NZ it is an electric powered saw that cuts by vibrating a saw blade. See e.g. https://www.bunnings.co.nz/aeg-300w-multi-tool_p0088692. The Leatherman derivative of the Swiss Army Knife is also called "Multitool".
The distinction is that a vibrating tool gets so hot at the cutting edge that nothing short of HSS can give reasonable edge life, and even that is way below my expectations for a useful tool. If you mean a hand tool a la Leatherman, heating the cutting edge is no issue, and any steel having 0.6% or more carbon is good enough after ordinary hardening. HSS retains its 60 HRC hardness to 550 Celsius or so, plain carbon steel is down to 40 HRC already at about 300 Celsius.
I have made myself a chisel for wood cutting out of 8x12mm HSS with a wooden handle, and it has not failed me, hammer blows or not. Is it any better than chisels made out of carbon steel? Of course not, edge holding is first of all determined by the steel's hardness, and secondly by the angle to which the cutting edge is ground (25 degrees or more for cutting timber). Toughness in the form of Charpy tests or equivalent is irrelevant for such small tool sizes. My steel-cutting scraper is also HSS, 25x2mm glued into a wooden handle.
But if you decide to use HSS, don't attempt to heat treat it yourself. That is for experts only, and they need to use rather sophisticated, electrically controlled ovens with salt or lead baths to ensure uniform and repeatable heat treatment conditions. If you need to machine HSS, buy yourself a carbide endmill advertised for 65 HRC. In thinner gauges, they are available from Aliexpress for under 10 US$ - they cut hardened HSS like the proverbial butter.