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Making a few tools for the wood lathe #3: Heat treating the tool blanks (for 01 tool steel)

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Blog entry by Bob #2 posted 09-02-2007 04:23 PM 2537 reads 0 times favorited 6 comments Add to Favorites Watch
« Part 2: Phase 2 - refining the blanks Part 3 of Making a few tools for the wood lathe series Part 4: Making up the handles »

Well, some disappointment for me this week:
After checking some metal heat treating companies here I find that they have (understandably) a $60.00 minimum for processing materials. The sort of leaves us little guys out unless we have a whole batch of tools to do at one time.
This has never been my good fortune.

So, luckily I had a casting furnace sitting around for years with nobody asking for one so it is now pressed into service as a heat treating unit.
heat-treat-1

Showing here is the furnace with a stainless steel umbrella stand and small electric heater to preheat the canola oil for quenching the red hot steel. You can use any oil wth a high flash point ( over 400° F and you should be O.K. . ( motor oil will work but I dont’ like the smell ) Olive oil corn oil etc etc.

The umbrella stand was fluke that showed up at my local Princess Auto store this week.
I leaks a bit but I will sweat a bit of silver solder around the bottom seam when I have time. ( Another poorly made, great idea from China!)

I needed something taller than my tool steel to prevent spattering – with fiddling, this will work, the heat required is less than 300° F so melting the solder out is not a problem.

heat-trea-3

This shot shows the two tools I’m making with monel wire leads through drilled holes to dip the hot iron in the canola oil . (This wire was scrounged from the old wire style heating elements from electric stoves.
I could do this with tongs but the wires make it easier to handle the pieces .
Were ready to go so I take the temperature up to 1450° F and let the tools soak at this temp for 20 minutes

heat-treat-4.

Now I take them out of the furnace and quickly into the hot oil to quench the steel.

Next step is to clean off the thick black scale with a rag and rinse off the residual oil .
When the furnace drops to 350° I put the tools back in and hold that temperature or 2 more hours to take the brittleness out an give the steel some resilience.

heat-treat-5

Here’s the result , all mottled and looking like junk but hopefully a few minutes with some abrasive and they will be ready to recieve their handles then back to the wood lathe.

Before I get everybody thoroughly confused I should give you some definitions of the stages of metal we are interested in here:

Annealing – Softening the tool steel for working, by heating to the hardening temperature and cooling slowly. Slow cooling can be accomplished by burying the steel in an insulating medium such as lime or vermiculite and allowing it to cool to room temperature.

Hardening – Heating the steel to the hardening temperature and cooling suddenly by quenching in an oil bath.

Tempering – Reheating the hardened steel to the tempering temperature in order to relieve stress induced in the hardening process, and remove some of the hardness in exchange for toughness. Untempered, hardened tool steel is nearly as brittle as glass.

-- A mind, like a home, is furnished by its owner



6 comments so far

View mot's profile

mot

4911 posts in 3500 days


#1 posted 09-02-2007 04:43 PM

Bob, wow. You’re poor wife is going to be sick of me this winter. LOL. Cool process. This is a great blog!

-- You can discover more about a person in an hour of play than in a year of conversation. (Plato)

View Bob #2's profile

Bob #2

3809 posts in 3485 days


#2 posted 09-02-2007 05:01 PM

Mot, my wife lets me do anything!

She’ll be happy to have you around.

I am a bit concerned that your wife may be a bit apprehensive when she finds you “sneaking” oxy acteylene and heat treating furnaces downstairs though! <vbg>

We are so clever – but—- they know

Bob.

-- A mind, like a home, is furnished by its owner

View mot's profile

mot

4911 posts in 3500 days


#3 posted 09-02-2007 05:37 PM

Just as long as I get rid of the box, Bob…just as long as I get rid of the box. :)

-- You can discover more about a person in an hour of play than in a year of conversation. (Plato)

View MsDebbieP's profile

MsDebbieP

18615 posts in 3624 days


#4 posted 09-02-2007 08:51 PM

this is interesting. Rick worked in the auto part manufacturing world for hmmm a long time :) and after retirement he did some delivery runs… taking products to heat treat plants. Now I understand the process a little more! Cool. or I should say “hot, hot, hot”.

-- ~ Debbie, Canada (https://www.facebook.com/DebbiePribeleENJOConsultant)

View Bob #2's profile

Bob #2

3809 posts in 3485 days


#5 posted 09-02-2007 09:57 PM

I’m sure no expert Deb and only learn enough to get the job done in most cases (Jack of all trades- master of none)
I’m just glad that I could share some of this stuff with the rest of you.

Cheers

Bob

-- A mind, like a home, is furnished by its owner

View Karson's profile

Karson

35035 posts in 3864 days


#6 posted 09-03-2007 01:56 AM

Great series. Thanks Bob.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware soon moving to Virginia karsonwm@gmail.com †

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