pitchfork heat treating

[mike landrich]

I have a bunch of antique pitchfork heads that were a barn that burned. They were to be used for the Scottish Highland Games, so they need to be able to withstand a lot of stress, which they were great for, before the fire.  The tines are bent. I'd like to straighten them, but have no idea what I would need to do to heat treat them, to retain and, hopefully, regain some of the spring qualities of the steel. Any advice?

 

Background on me. I've done a lot of welding and fabricating, but have no experience as a blacksmith. I would most likley do the heating and straightening using either an OA or oxypropane torch. I could do a primitive coal forge if needed though, if there is an advantage

[Latticino]

I'm not too familiar with use of pitchforks in a highland games setting.  Are they thrown at a target (in which case toughness is more important than hardness and I would just straighten the times by heating with your torch and hammering to shape over a stump) or used to fork up large, multiple bales (in which case you might want to heat treat them)?  Please note that many forged garden tools are not made from high carbon steel, so heat treating will not be effective.  The easiest way to tell definitively if your forks are high carbon would be a quench and break test, but that is destructive and you would sacrifice some material.

If I had to do heat treat I would (assuming they are high carbon steel):

1. remove the shaft
2. heat to just above non-magnetic (ideally all tines simultaneously, which likely puts you in a larger coal fire, but might be able to do individually depending on configuration)
3. quickly quench in 140 deg. F vegetable oil (hopefully a relatively shallow pan that can take all times at once if that option is selected)
4. temper twice  in large oven at 450 deg. F for an hour each time

If not high carbon, then you are pretty much stuck with just work hardening.  With any luck you will get a better response from someone who has actual hands on experience repairing pitchforks.

[JHCC]

The "sheaf toss" is a traditional Highland Games event wherein the competitor uses a pitchfork to throw a burlap bag filled with straw over a high bar. 

Since you don't need high strength (as you would with moving lots of heavy bales), I wouldn't worry too much about tempering for maximum strength. Reforge and normalize; if you do want to try tempering (and the carbon content is high enough), go with Latticino's advice above. 

[Smoggy]

I'd also suggest reshaping one (a gas torch would suffice one tine at a time) and fit with a temp shaft to try it out. You should know then if they require any heat treatment or not and can set up as needed to work the rest.

Keep us upgraded on your progress and a few pictures never goes amiss here.....best of luck.

[ThomasPowers]

Stop by the smithy and I'd be happy to give you some basic lessons on working high carbon steels as pitchforks generally were.

[jlpservicesinc]

 If they were vintage pitch forks,, 2 or 3 tine (3 tine were rare on small farms) then they most certainly were hardened and heat treated..    

A vintage 2 tine pitch fork in the normalized state will twist up like a pretzel in use.. (I have made vintage 2 tine types for moving loose hay) They have to be hardened and then a peacock or purple temper.. Just like a spring..      As a bragging rights kind of thing.. It was said who ever could make a pitchfork to the exact pattern, model, thickness.. etc, etc.. And the 2 tines would bend to touch and then spring back with no distortion was consider a master/ workman of the day..

 

Oil quench then smoke off should work great.. 

 

Real question is.. What kind of pitch fork?     They only made 200 different kinds..  Thus a picture would help pin point the right way to solve the problem.. 

[mike landrich]

On 4/7/2017 at 5:05 PM, jlpservicesinc said:

 If they were vintage pitch forks,, 2 or 3 tine (3 tine were rare on small farms) then they most certainly were hardened and heat treated..    

A vintage 2 tine pitch fork in the normalized state will twist up like a pretzel in use.. (I have made vintage 2 tine types for moving loose hay) They have to be hardened and then a peacock or purple temper.. Just like a spring..      As a bragging rights kind of thing.. It was said who ever could make a pitchfork to the exact pattern, model, thickness.. etc, etc.. And the 2 tines would bend to touch and then spring back with no distortion was consider a master/ workman of the day..

 

Oil quench then smoke off should work great.. 

 

Real question is.. What kind of pitch fork?     They only made 200 different kinds..  Thus a picture would help pin point the right way to solve the problem.. 

 

I have 10 different forks. Most are indeed 2 tine, since I throw in the Northeast, where we can use them. I'll just start by straightening and then see about hardening

 

 

Thanks to all who replied. I will take before and after pics and post them then

[jlpservicesinc]

Pictures are worth a thousand words anytime iron work is involved.. 

[mike landrich]

21 minutes ago, jlpservicesinc said:

Pictures are worth a thousand words anytime iron work is involved.. 

I'll get, and post, some tomorrow.

[Andrew_]

Reading this now (working on straightening prongs on a "normal to me", five prong pitchfork. (which currently has just four prongs)

 

So disappointed not to find any pictures... 

I came here following a YouTube video that said just to use a vise, and a long piece of pipe for leverage on the tine and bend it back that way.  

[BsnNFrnt]

I have made several Highland Games forks and “modified” traditional pitch forks for the games. I would suggest using heat before trying to straighten the forks, in my experience the tines will likely break. 

[George N. M.]

I'd be careful about cold bending in a vise.  I'd be leery of either snapping the tine or putting enough metal fatigue into it that it would bend again in the same spot.  I'd bend it hot, quench, and retemper the bent tine.  Easier done on an outside tine.

"By hammer and hand all arts do stand."