Remaking floor jack parts - alloy?

[HemiRambler]

The love affair with my old Blackhawk dictates I must remake the very worn pump housing. Normally I'd attempt to sleeve such a part but the wall is so thin on one side that approach doesn't seem feasible.

So my question is - what steel should I use to make this part. The OEM part doesn't appear all that hard, but seems better than COLD ROLLED. With no knowledge on this I was leaning towards 4140 or even 4140HT.

Suggestions are appreciated!!!


Jacin

 

[A_Pmech]

It's hard to even begin with a recommendation without seeing the part.

 

[soupy1957]

Generally speaking, "X750" or "Tool Makers Steel" is sufficient for most applications. A Pmech is right.........pictures speak volumes.

 

[HemiRambler]

I stopped over a buddies last night (retired machinist) and he recommended a number of alloys including "TRS" Tool Room Steel - sounds like the same stuff you are talking about.

Not sure what I can scrounge up so I appreciate the input.

BTW here's a pic - the HEX PART part on top is the piece that needs replaced - the shaft below is fine. The shaft goes inside the hex part.

 

[sberry]

I bet that fitting can be bought off the shelf and then has a minor amount of machining done to the inside?

 

[HCRCnow]

Can you give us the model number of the jack


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[A_Pmech]

I bet that's just a leaded screw machine steel. It's not hard at all, judging by the marks your box end wrench left on the flats.

 

[laser3kw]

I bet that's just a leaded screw machine steel.

agreed.
12L14 or similar
hot rolled would be an improvement, 4140 is good as long as you can get good surface finish. A good reamer should size and finish it nicely.

 

[JESTERxHEAD]

I'm new here, figured this would be my first post.

If I'm looking at this correctly the fitting part of the jack pump is more than likely 12L14 leaded screw machine steel. However the piston that's just below it should be made out of dissimilar material, 4140 pre hard (28-36 HRc) would be a perfect option for it or 4140 annealed (14-26 HRc) A reamer or even a piece of emery cloth on a small rod affixed to a drill would "hone" and polish it enough for a cylinder bore.



If I'm looking at this completely wrong my apologies...

 

[Hiball]

Can you give us the model number of the jack


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Looks like a sears version of the Blackhawk SJ1/2 based off the 2 piece pump cylinder/cap, suppose it could be a early SJ also.

 

[HCRCnow]

I was hoping to get hemirambler to let us know what the part is off of. So i could see if its available.

Hiball, the pump on the SJ1, on my drawing is one piece. No threads on the top. If this was made differently i can not find it.


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[Hiball]

I was hoping to get hemirambler to let us know what the part is off of. So i could see if its available.

Hiball, the pump on the SJ1, on my drawing is one piece. No threads on the top. If this was made differently i can not find it.


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I really think its a Sears issued characteristic, I'll see if I can find the pictures, but I remember the first time I seen it, I was like what the Hell is that..

Here you go Marc... Stolen from jawnd393

 

[HemiRambler]

I can't say with any certainty who made this jack. I was told by the Original Owner that it was a Blackhawk, but other than his word I can't really say. The original paint was RED if that helps. I was most definitely the FIRST person to take it apart - you could see the paint "break" as I dissembled it.
You guys tell me - I can't find a tag on it anywhere.

Well you guys got me to thinking maybe it was intended to be "soft" - so I chucked the old one up in the lathe and took a test cut. Yeah this thing is definitely "leaded". And it just so happens I have a chunk of 12L14 laying around.


To be Continued!!!!

 

[HCRCnow]

Hemirambler, this part is available. If you have an interest PM me.


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[HemiRambler]

HCRCnow, I wish you'd have said that earlier!!!!!! ;-)
I ended up making one out of 12L14. Good to know I can get one if my fabbed one craps out!!!!


It's back together working and yet to be tested - A couple bolts were bent and I want to replace those before any testing!

Thanks to all who commented - I appreciate the guidance!!!!!