Steel grade recommendation

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ecdez

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I have a small production run of specialized gear pullers I'd like to make and one of the parts I'd like to do on my turret lathe. The part looks like the item blow. I could just buy the "bolt" but then it wouldn't be made by me and the cost of the bolt would push me too close to my target sell price.

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I plan to use hex stock and I have a box tool to turn the diameter and a die head to make the threads. The question is, what grade steel would be best for strength and ease of cutting? I do mostly aluminum so not much experience with steel.

Thanks in advance!
 
What grade of steel in hex is available at a affordable price is the question, having only small hex head may be more economical just to machine a hex on a round piece of bar, that way you can use cheaper, better quality material, also to consider is what type of finish are you using on the finished item, i've used 17mm C45 hex on a similar project and had the finished items hardened, which left a black finish and i counted them in cosmoline, do your calculations first because is hard to be cheaper then cnc manufacturing.
 
My first thought would be 1144 Stressproof.
 
A gear puller bolt will need to be hardened to take heavy loads and to have a good lifespan. 1144 does not harden well. I would tend to forget about using hex stock and machine the head to hex. Actually, I would first look for something made in quantity by someone else...
 
Were it me, I'd make them from ETD-150 and mill the hex. Similar to pre-hardened 4140 with better machinability. Alternatively, make them from a Grade 8 bolt.

If buying the bolt would cost more than making them, something is upside down.
 
I like 41L40 but I'm not sure it would be appropriate for a gear puller screw. But, it machines well.
 
Might I suggest doing your first bolts for another project, one less likely to injure your buyers if it all goes sideways. I use gear pullers quite often, and you can really put some stress into those bolts. If it broke, blood could easily be spilled.

Also, small batch hardening and tempering (required for this part) is not cheap, unless you have your own oven and know what you are doing.

Sorry if I sound like Ms. Debby Downer.
 
A gear puller bolt will need to be hardened to take heavy loads and to have a good lifespan. 1144 does not harden well. I would tend to forget about using hex stock and machine the head to hex. Actually, I would first look for something made in quantity by someone else...
Also Stressproof can fail in torsion. I'd likely use 4140 HT
 
What kind of hourly rate do you want to make with this product? If I make a bolt from hex, I would be making about $1/hour. I can buy one for $.75.
 
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