Real 1144 "Stressproof"

[jgedde]

I bought 3' of 1144 from a big name industrial supplier to make a crankshaft for my Panther Pup engine. Despite making fixtures to keep the crankshaft from flexing and collapsing, and trying three different methods of machining the throws (including using the toolpost grinder) I now have three warped crankshafts. Some warped by as much as 0.030"! Not the 1144 I remember using in the past...

Not only that, the stuff I bought machines like 1018 not the 1144 I've used in the past.

Where are you guys buying your 1144 from? Any recommendations of a house that sells real LaSalle Stressproof steel? Any other materials I could use instead that exhibit ultra low warpage during machining?

John

 

[toolznthings]

Small pieces from McMaster Carr when I need it quick, or Alro steel.
Sounds like you got something besides 1144.

 

[jgedde]

Small pieces from McMaster Carr when I need it quick, or Alro steel.
Sounds like you got something besides 1144.

Thats where i got it from... McMaster...

John

 

[mcostello]

Why don't You tell them and see what they say?

 

[GailInNM]

I have been very happy with the 1144 that I have bought from Speedy Metals.
http://www.speedymetals.com/c-8238-category.aspx

I have bought 1144 from thm about 1/2 a dozen times. I generally buy my 1144 as TGP ( Turned Ground Polished). TGP has a diameter tolerance of *0/-0.001 in under 1 -1/2 inch diameters so it is very consistent. Used mostly for Swiss Screw machines where that is a must. Costs about twice as much as cold finished 1144 but is well worth it for me.
Gail in NM

 

[jgedde]

Small pieces from McMaster Carr when I need it quick, or Alro steel.
Sounds like you got something besides 1144.

Thanks for mentioning Alro.

I emailed Niagara-LaSalle and they told me Alro is an authorized dealer for their product. I ordered a new piece from Alro and hopefully it'll all work out.

I've been making crankshafts for over a month! It's getting old...

Here's what I've been doing. Maybe someone can tell me where I might have gone wrong...

1) Center drill the stock on each end.
2) Machine the round stock to be flat on two sides. Final dimension is .015 oversize on purpose.
3) Center drill each end in two additional places: the centerlines for all of the throw journals.
4) Rough machine away most of the material.
5) Install small jacks between all of the throws to keep crank from collapsing whilst between centers. When a particular journal is being machined, all of the remaining throws have the little spacer jacks installed.
6) Turn the throw journals. Leave .015 oversize.
7) Turn the center bearing journal. Leave 0.015 oversize. (The turning operations chatter like mad!)
8.) Set up the toolpost grinder and finish grind all of the journals.
9) Turn the ends of the shaft to size.
10) Surface grind the crankshaft to final thickness.

Having just written this, I wonder if reversing operations 3 and 4 will help at all. It would be nice to be able to easily machine the ends first (Step 9), but then I'd have no place for the two outboard centers and it makes the workpiece even less rigid.

I had a thought of stress relieving the metal after rough machining by putting it in my kitchen oven and running a cleaning cycle (900-950 degrees F)! My wife'll think I'm nuts and she probably be right! I wonder if that's hot enough?

John

 

[Blogwitch]

On the rare occasions I have had to make a multi crank, I didn't use jacking screws as they impart an outwards pressure just to stay in place, I cut some blocks up of the correct length (any metal material), but not a tight fit at all, and stick them in the gaps with 5 minute epoxy but allow it to dry for an hour, holding everything in place with masking tape. That way you have no pressures at all trying to bend your crank.
A few seconds with a blowtorch soon releases the epoxy.

John

 

[gbritnell]

Hi John,
Here's the link to a tutorial I did on making a crank. Maybe it will help you out.
gbritnell
http://www.homemodelenginemachinist.com/showthread.php?t=5011

 

[jgedde]

On the rare occasions I have had to make a multi crank, I didn't use jacking screws as they impart an outwards pressure just to stay in place, I cut some blocks up of the correct length (any metal material), but not a tight fit at all, and stick them in the gaps with 5 minute epoxy but allow it to dry for an hour, holding everything in place with masking tape. That way you have no pressures at all trying to bend your crank.
A few seconds with a blowtorch soon releases the epoxy.

John

Thanks for the info. My jacks have a cross hold drilled through their base. I sandwich them between plates that are clamped onto the crankshaft to hold the jack in place. That way I don't need to tighten them so that they deform the crankshaft. They're basically installed so that the jack screw just touches the opposite side, then a 1/4 turn more to snug it up. Then the lock nut is tightened and the clamp plates are installed. They go in loose enough that they can easily be pulled out by hand without the plates installed.

Like this:

 

[jgedde]

Hi John,
Here's the link to a tutorial I did on making a crank. Maybe it will help you out.
gbritnell
http://www.homemodelenginemachinist.com/showthread.php?t=5011

Thanks! What I did is very similar. The main difference between what you and I did is that you made those block to offset the crank vs. me using three center drilled holes. I like your method because the block helps rigidity! It's not clear to me what holds the crankshaft in the blocks though.

My second attempt at the crank used little pieces of aluminum glued in between the throws using CA glue. Very similar to what you did. My third attempt used the adjustable jacks.

I can't wait to get real StressProof(tm) from Alro... The only thing I can think of at this point is that the 1144 I bought from McMaster wasn't stress relieved properly. That and it is machining like 1018... Not like the 1144 I've used in the past. What's stranger is that this stuff doesn;t even seem to be consistent along the 3' I purchased.

John

 

[MachineTom]

I recently purchased some 1144, from speedy I believe. StressProof is material that has been cold worked, so its round, and straight. However internally it appears that there is still material that is under its own stresses, as a piece on .875, turned to .500 for a length of 3", moved .030 overnight after being machined.
To correct that, I broke out the O/A torch and heated up the junction area that was turned down, then tapped it straight'. worked well.

 

[gbritnell]

This reply isn't meant to get into a debate about what is and what isn't stress proof steel but rather to present my experiences with said material. Since I was put onto 1144 steel many years ago I have used nothing but for my crank making and I can honestly say that I have never had it distort more than .002 on even the most complex shaped cranks. I have even used it for a lot of parts that I previously would have used 12L14 steel for. It machines very nicely with high speed tooling and it doesn't rust like 12L.
As far as McMaster, I would contact them and explain your experience.
gbritnell

 

[jgedde]

This reply isn't meant to get into a debate about what is and what isn't stress proof steel but rather to present my experiences with said material. Since I was put onto 1144 steel many years ago I have used nothing but for my crank making and I can honestly say that I have never had it distort more than .002 on even the most complex shaped cranks. I have even used it for a lot of parts that I previously would have used 12L14 steel for. It machines very nicely with high speed tooling and it doesn't rust like 12L.
As far as McMaster, I would contact them and explain your experience.
gbritnell

I too have had good luck in the past with Stressproof 1144. That's why I'm using that instead of CRS with torch stress relief as recommended by Mr. Reichart's plans.

I will see what happens after I try my hand with the real 1144 StressProof from LaSalle. If it still warps, it's my fault.

I've learned quite a bit about 1144 since I started this thread:

LaSalle invented and patented 1144 StressProof (tm) in the 30's. The ASTM spec that covers 1144 (ASTM A311) even has a special class (Class B) for LaSalle's product vs other 1144 stock. This info comes from LaSalle' marketing information so it can certainly be considered biased.... So take it with as many grains of salt as you like.

What I have learned definitively is that not all 1144 has been processed the same! It is available hot rolled, cold drawn, cold drawn with deep draft (whatever difference that makes). Worse yet, the mechanical properties between A311 Class A 1144 and A311 Class B 1144 are notably different!

All 1144 that conforms to ATSM A311 has been stress relieved to meet the mechanical properties called out by A311 (Table 2) - which doesn't include any information about internal stresses. So, I read this to mean that we're not guaranteed a fully stress relieved product. I wonder if this explains the mixed results?

In any event, LaSalle claims they do a warp test of their material periodically and whenever a forming die has been changed out.

Hot rolled 1144 does not conform to the ASTM spec at all and is not stress relieved. That said, by nature of it being hot rolled, I would expect it to have lower internal stresses than unrelieved cold drawn 1144.

An interesting bit of trivia is thsat the A311 spec covers other carbon steels besides 1144! That surprised me. Here's a link to a edited version of A311: http://www.fushunspecialsteel.com/wp-content/uploads/2015/09/ASTM-A311-Specification-for-cold-drawn-stress-relieved-carbon-steel-bars-subject-to-mechanical-property-requirements.pdf


I did buy some 12L14 to try as well. I've never used it for warp sensitive machining projects, in fact I have only used it once before. I wonder how it will do?

John

 

[toolznthings]

Hi,

McMaster will stand by their sale so you should maybe give them a call. Explain that the material is not cutting correct and you are knowledgeable.
Your are not getting the crank hot from the grinding operation by chance ?

Brian

 

[10K Pete]

I started using StressProof (tm) back in '83 for production of some parts. At the time I took careful notice that StressProof (tm) derived its mechanical properties from the specialized cold working it was subjected to by LaSalle Steel. At that time I was not aware that there was an 1144 designation. Said designation seems to have been confused these days with the StressProof (tm) product.

When I need a good steel with good machining properties I buy 1144. When I need the specific physical properties of StressProof (tm) I buy, and receive certifications for, StressProof (tm).

Pete

 

[jgedde]

Hi,

McMaster will stand by their sale so you should maybe give them a call. Explain that the material is not cutting correct and you are knowledgeable.
Your are not getting the crank hot from the grinding operation by chance ?

Brian

Thanks Brian,

I'm still not 100% sure it's the McMaster material. There is a decent chance it's me or my technique. I don't feel comfortable complaining until I know for sure.

I'm virtually certain it's not a grinding problem since the first crankshaft was fully turned, not ground. I only went to the grinder because chatter was an issue. At that, I was only taking a few thou at a time.

Oddly enough, and this may be another clue: a few times I took a break. When I came back and ground another few thou, I noticed the sparks occurring irregularly (sparking out once per revolution). No changes except for time. This, of course, would clean up after a pass, but it makes me wonder....

John

 

[jgedde]

I'd like to thank George, Brian, Pete, Tom, Gail, John, et al. for responding with helpful information! I don't mean for this post to close the discussion, just to thank you all for your time...

John

 

[jgedde]

Things are getting even more gnarled up with the 1144 deal:

1144 is available in:

1144M FatigueProof
1144 Stressproof and equivalent (ASTM A311) including TG&P
1144 Cold Formed
1144 Hot Rolled

Alro stocks them all... Here's a link if you want to compare them all:
http://www.alro.com/divsteel/metals_comp_type.aspx?Mat=CARBON%20STEEL&Type=Bars&mc=CS

So, when we order 1144 for a low stress material, we need to make sure it complies with ASTM A311 Class B. Class B is important...

John

 

[petertha]

Add one more naming varietal: Cold Drawn Stressproof 1144. I've yet to do anything serious with my stick, but its going to get a try for a cylinder liner & a crankshaft. The C/S is not as complex as yours.

With OLM you get a manufacturer spec sheet for everything purchased so at least some confidence what's in the box corresponds to a specific alloy/standard.

https://www.onlinemetals.com/merchant.cfm?id=286&step=2&top_cat=197

 

[jgedde]

OK fellers,

I bought a new rod of 1144 A311 Class B Yesterday from a local house (A311 Class B but not LaSalle according to the material certs). The real deal from Alro wasn't supposed to arrive til early next week and I didn't want to lose the weekend. Wouldn't you know it, the Alro StressProof showed up today.

In any case, I started a new crankshaft last night using the stuff I bought locally. Things are going MUCH better... No warping to speak of.

John