Need a Straight Edge?

Check with Busch, I believe they told me it had been stress relieved once already. When I cast them, I get them high temp stress relieved after casting and then rough machine them and then high temp cook stress relieve them again. That means heat it to about 1100 degrees and cook it for 2 hours, lower heat to 900 to cook for 2 more hours, lower to 600 deg for 2 hours, lower to 400 for 2 hours and then shut off the heat and let it stay in furnace for 2 hours...then let it cool to room temp. You can screw around and make a home made oven, but I have found it to be unreliable, so send it to a pro. They will set it on steel plates usually at the airy points or 30 %. Some will drill and tap a hole in one end and hang it in the furnace. I have to scoot...more later. Rich
 
Well maybe I will not cut it up. I have been looking on ebay for only about a month and have not seen any 24" long straight edges. I think I need to relax with the book Machine Tool Rebuilding and learn more about making things flat. And I am interested in hearing more about stress relieving as is being dicussed here!

Ray
 
Marshall said:
I can fit a 24" piece, I think, in my heat treat oven, but I don't think I can fold up a 48" and make it fit.
Marshall
Click to expand...

Marshall,
I suppose using my OA torch to pierce a hole in the side of your oven so that you can do 1/2 of it at a time is a reasonable answer...



My 48" arrived today. I ordered yesterday morning, easy to work with!
With that type of service I should consider purchasing additional items from them when/if the time comes.
 
I'll be starting boxes on Monday or Tuesday.
I want to complete the fabrication of a 2 step flat belt pulley for my shaper.

Thus far I show 4 requests for boxes:
Marshall
Shopsweeper
Turbotadd
Uglydog

Anybody I missed?
Did anybody not order from Busch, or doesn't want a box.
Did we all get 48inch?

Please send me a PM with a ship to address.

Daryl
MN

IMG_0746.JPG
 
I am in for a 48". I spoke with a very nice person who works with Bob the other day while I was driving across Arkansas (she was very concerned that I might have my phone in my ear (it was on bluetooth audio)).

So I THINK UPS has a big chuck of Fe with my name on it right now.

Thank you so much, Richard for finding and sharing this gem (and for a promoting a remaining NA manufacturer). I hope that all of us have our castings made into an edge worthy of your gesture.
 
No Problem.

When you get it, I would drill and tap a hole in the end and insert an Eye-bolt to hang it from the end. Draw a X on the end on the beefier part to calculate the balance point where you will drill the hole I have found over the years this is the best way to store straight-edges. The same principal as storing a ball screw. If your not in a hurry to use it, set it outside and let Mother Nature stress relieve it. The old time machine builders would set their castings outside for 5 years to heat up and cool in the summer and winter. I have also heard Henry Ford did that to his engine blocks too. While machining and scraping them, hang them up using a rope or nylon strap and take a block of wood or dead blow hammer and rap them to "RING" them like a bell a few times during your SE. This vibrates the iron to help stress relieve it too. If you need any other help please ask. Rich
 
Richard King said:
No Problem.

When you get it, I would drill and tap a hole in the end and insert an Eye-bolt to hang it from the end. Draw a X on the end on the beefier part to calculate the balance point where you will drill the hole I have found over the years this is the best way to store straight-edges. The same principal as storing a ball screw. If your not in a hurry to use it, set it outside and let Mother Nature stress relieve it. The old time machine builders would set their castings outside for 5 years to heat up and cool in the summer and winter. I have also heard Henry Ford did that to his engine blocks too. While machining and scraping them, hang them up using a rope or nylon strap and take a block of wood or dead blow hammer and rap them to "RING" them like a bell a few times during your SE. This vibrates the iron to help stress relieve it too. If you need any other help please ask. Rich
Click to expand...

Richard,
Please clarify.
Hanging a straight edge is preferable to a wooden box?
Your wisdom and experience certainly trumps my assumptions.
If so, I will retract my box building effort offers in deference to better tool storage options.
I just double checked Connelly. I don't see that he addresses tool storage best practices.

I am confused about how to calculate the best location for "Draw a X on the end on the beefier part to calculate the balance point where you will drill the hole". Please clarify. Thank you.

Hope your blood pressure is improving!
 
You'll have to count me out on the box deal. I've already got a 48" (Challenge Machine) and the shipping costs would take this deal out of the "killer deal" category.
Thanks again for the offer!

Tadd
 
Uglydog said:
Richard,
Please clarify.
Hanging a straight edge is preferable to a wooden box?
Your wisdom and experience certainly trumps my assumptions.
If so, I will retract my box building effort offers in deference to better tool storage options.
I just double checked Connelly. I don't see that he addresses tool storage best practices.

I am confused about how to calculate the best location for "Draw a X on the end on the beefier part to calculate the balance point where you will drill the hole". Please clarify. Thank you.

Hope your blood pressure is improving!
Click to expand...


A box is for shipping, not storage. Or if you need to take it to a job, you put it in a box. The best way to store them is laying on a granite plate, but no one has room to do that. Several years ago, I taught a class at Honeywell in New Brighton MN. Much like many of the big companies in the USA years ago they had a machine repair group who rebuilt machinery and those guys retired and never taught anyone to replace them, so the skill was lost or faded away. Well anyway, Honeywell wanted to revive the scraping team. After our classroom session we went to the area where they used to scrape in maintenance and I said I wonder if they have any straight-edges? The foreman said.. "there are some hanging in the cabinet over there, No one has used them in 25 years. We proceeded to open this closet looking cabinet and in there hanging from eye-bolts were 4 or 5 straight-edges. 3 camel backs; a 6' King-Way brand, a 4' Busch and a 3' Brown & Sharpe. and some home made triangles..I can't recall the lengths. We took them out and checked them on a granite table and all were straight as an arrow and scraped to 40 PPI by hand. Since that time I have told people to hang them from an eye-bolt. We used to make straight edges and I still have the wood patterns. But I got sick of everyone wanting a deal as they had no clue how much time it took to make and scrape one and complained about the costs. So I said to heck with it. When we sold one we made a shipping box and supported them on felt covered wood blocks placed at 30%. The box is a nice idea, but I would save my time and hang them. Rich
 
Uglydog's question and Mr. King's comments got me researching last night when I should have been sleeping.

1. You can search for a thread titled: "Straight edge storage" over on Practical Mechanist. This post seemed to start when a member made made a DUAL-use wooden box (both a stand and a storage box) so it's useful for our discussion here.

2. You can search for another PM thread titled:"Storing Cast Iron Straight Edges" on PM too. I could link them both here but I'm not sure about the propriety of such activity. This second thread is full of opinion, facts (many OT), and reports of practice. I can summarize by saying that "opinions are varied". I learned a lot including the concept of "Airy points" and "fifth points".

3. I asked dad (retired mechanist) and he said that he used to: "Store it flat side down on the granite surface plate at all times". This is not going to work for my 30" surface plate and my 48" edge.

4. I worship along with a metallurgist who makes his living testing, measuring and certifying metals (mostly for the energy business) and I will seek his opinion when I can. My 'ammo in exchange for metal advice' program may be need to be augmented with lunches to get this kind of answer. If I get anything relevant I will post it here.

I think the good news is that my casting is not YET a precision instrument and I have some time to get a plan going.

The question I have is; "What is going to make the iron 'creep' at room temperature"? The only answer I can come up with is; "unresolved internal stresses within the part itself".

The next logical question is; "Why is laying on a flat or hanging going to prevent this?". And I am not able to approach this question due to lack of knowledge.

Both the long PM thread and dad hinted at a book titled "Foundations of Mechanical Accuracy" by Moore. My inter library loan clerk is going to hate me.
 
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