Making A Socket Firmer Chisel

[Preston Baxter]

Some folks were interested in seeing the details of how I made my mortise chisels. I made a 3/8" firmer chisel yesterday and took some photos along the way to show the process.

The round blank is chucked in the lathe and the socket is turned to a taper using the compound slide set to 5 deg.
This lathe is not really well suited to turn tool steel. It lacks the rigidity to make all but light cuts. I'm eventually going to install a compound slide on my Hardinge Mill so it will be able to quickly do this task instead.


Here the shoulder being roughed out:


Here is the completed socket after polishing:



The part is now being supported by a steady rest, and the socket hole is being drilled out to the root size using the tailstock:



After drilling, I switch to a boring tool mounted on the compound slide which is set to 5 deg. This pic was taken after taking the final finishing cut:



Here is the part with all the lathe work done. The small round shoulder was turned to the proper diameter to give me a reference check point during the milling process.


Since messages are limited to 15 images, I'll add rest in a separate post.

[Preston Baxter]

The part is now clamped in a vice in the mill. There is a spacer under the part to give support.


The first side has been milled with a couple of roughing passes and a final finishing pass. This nearly 60 year old machine can really hog off metal.


The second side is complete.


The third side is done, it's starting to look like a chisel.


Next, I layout the taper for the face side of the chisel:


Milling the final, face side.


The part straight off the mill:




The tip is then hardened with a MAPP torch and peanut oil. The dark color on the first third of the blade shows the extent of hardening. From here, the chisel will be tempered in the kitchen oven for thirty minutes at 350 deg.


After tempering, the chisel is flattened on a cast iron lapping plate. Here I am charging the plate with 120 grit compound. It just takes a little. Too much, and the part just slides around without the grit embedding in the plate once lapping commences.


The plate will start to get sticky as the steel residue mixes with the grease. Just wipe the plate off with a little Kerosene or Mineral Spirits and continue lapping until the grit breaks down, then recharge. I keep meaning to try just some plain dry grit and Mineral spirits since the compound has a bad sulfur smell. After lapping all faces, I finish up on oilstones.


I turn and fit the handles pin to the socket first, then complete the handle:



Here is the finished chisel. It works beautifully.




Here it is beside its big brothers:

[george wilson]

That's a lot of work! I'm surprised that that 6" lathe will cut the steel. I started out with a 12" Atlas,and it was a pain to get anywhere with. I couldn't take off more than 1/32" at a pass!

[Jim Koepke]

Thanks for showing this.

I wish I had taken metal shop when I was in school. This makes it look easy enough that maybe I could book learn if I had the machines.

Sure is an interesting subject for the neanderthal galoot.

jim

[harry strasil]

I took metal shop while going to school even tho the school didn't have a metal shop, I was still an apprentice blacksmith under my father and uncle. LOL

[Preston Baxter]

I would like to learn some basic blacksmithing skills someday. It would come in handy for projects like this. In this case, I could start out with a much smaller bar and upset the socket end to the larger diameter and have a less machining and metal waste.

[harry strasil]

the old method was to upset a bit, then flare out the end and form it into a socket then forge weld the seam, lots of old chisels you can see the seam inside the socket. Also the socket and chisel were made as seperate pieces and then forge welded together. Tang are much easier to make so there were a lot of them in the real early days.

I have used ordinary black pipe to replace broken off or really mutilated sockets by first swaging out one end, then fullering down the other end and welding to the old blade socket stub.

[harry strasil]

FWIW, Preston Upsetting is one of the harder things for most Smiths to do, as they tend to get too much of the end hot and then all the hot end wants to do is bend over when they hit it. I have made what I call an Upset Helper that makes the task much easier. Its just a 2 inch square piece of hot rolled with gradually larger holes drilled in it and a square shank that fits into the Hardy Hole of the anvil. To use you install the upset helper and then heat only about 1 inch of the end of the piece you want to upset and drop it into the hole as quick as you can and start striking the top end while holding with a pair of tongs, it will want to bend over but the hole restricts it to only so much bending, you then take it out straighten up the end and then you reheat and drop in a larger hole, they progress by 1/8 inch larger and do it again. It works rather well, just remember to only heat the very end of the piece.

[Keith Christopher]

SIGN ME UP FOR A SET ! Thanks for the play by play. I loved it. It is funny with the flash and all they almost look like copper.


Keith

[Jonathan McCullough]

Fantastic work. Two questions: what kind of tool steel are you using? And how were you able to get the taper on the lathe? Did you just set the compound on an angle and advance the compound instead of the carriage?

[george wilson]

He said 01 somewhere else.

[harry strasil]

Angled Compound = Independently Poor Machinists Taper Attachment.

[James Taglienti]

That was really cool.

[Roy Wall]

Preston --

Sensational Thread......Awesome work.

Those are beautiful chisels - thanks for sharing your talent!

[Jim Koepke]

Harry,

With your upset helper, could you then have a similar helper only with a cone inside to start the formation of the socket?

jim