Need info about stainless steel for LF springs

Discussion in 'Camera Building, Repairs & Modification' started by Jim Chinn, Mar 9, 2006.

  1. Jim Chinn

    Jim Chinn Member

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    I am starting work on a 8x10 reducing back for an 11x14 camera. I am using the back on my Commercial View for a rough guide. The parameters of this job require stainless steel for the springs.

    I am woefully lacking in materials knowledge concerning stainless steel grades and designations. So I have a few questions for anyone with knowledge about stainless that is used for camera springs.

    I assume the springs are made from the same grade of stainless that a fairly stiff spatula or pastry knife is made from. The springs on the commericial view are .040" thick. Is this type of stainless, already tempered for flexibility available as stock or would you need to buy stainless and heat treat and work it first to achieve the qualities required for a spring? (outside my range of ability).

    If it is available what is the grade designation? (301, 302, 17-7 etc)

    I can buy commercial grade spatulas and flexible knives up to 18" long and cut out springs on a water jet. It would be better to be able buy a piece(and less expensive) 20"x20" to cut pieces from for future projects if available.

    Thanks in advance for any and all answers.
     
  2. Donald Qualls

    Donald Qualls Member

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    Have you looked in a kitchen shop? I've seen cake frosting knives made from stainless in that thickness range that sell for a few dollars each; the blade carries through the wood handle, so you should be able to get a pair of spring strips (cutting on both sides of the rivet holes in the tang) from one such knife.

    OTOH, if you're not wedded to stainless, have you looked at a leaf rake for spring stock? The tines are just about perfect...
     
  3. Donald Miller

    Donald Miller Member

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    If you can find a machine shop that has a metal cutting band saw then the worn out or broken blades make excellent springs. If the thickness is inadequate then one could always build a leaf spring arrangement with shorter subsequent lengths

    Most of the stainless steel that I have encountered over the years has been 316 and it has a certain degree of spring to it...but I don't think that it qualifies as spring steel.
     
  4. AZLF

    AZLF Member

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    The flat raw spring stock I have purchased for past projects did not come tempered. You would have to have that done or do it yourself after cutting and shaping.You can buy flat spring stock in a number of thicknesses, I bought mine from Brownelle's which is a gunsmithing specialty house. Were I to need to make something like a spring mechanism for a view camera film back I would probably do as others have suggested and find something already tempered that had the size needed and cut my spring pieces from that. Tempering requires precise temperature and time for the given stock and is especially hard to do in a home shop envirorment unless you have an oven that can reach 700+F reliably. My few attempts at it were not successful.
     
  5. Jim Chinn

    Jim Chinn Member

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    The pastry knives will work, but difficult to cut something that narrow on a water jet without having to make a jig to hold it. With a bigger piece I can duplicate the shape of the commercial view springs.

    You are right about the bandsaw blades Donald. I have made springs out of scrap and it works perfectly. However this back goes on a camera I am selling so I need the more "professional" look of stainless. Regarding 316 stainless, I think I have used it for other purposes. In the raw form I get it in it is flexible but fatigues and loses its "spring" with repeated flexing. I think 316 is a grade that with heat treating or chemical "pickeling" you get the combination of hardness and flexibility for springs. (two thngs beyond my capabilities. I think heat treating stainless for temper and hardness requries about 800F.)

    The pastry knives are actually the cheaper alternative after doing a quick google search. So if I can't find a source for stock of that particular stainless I will be heading over to the local restuarant supply house.
     
  6. Kino

    Kino Member

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  7. Aggie

    Aggie Member

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    Bob Coogan at the Appalacian Craft Center in Smithville TN. will know exactly what you need, and where to get it cheaply. Just tell him I told you to call. He is not there on Friday's. Tempering is easy to do if you have a blow torch. It is t6he color the metal heats up t6o that you need to know for each particular type of SS. Some take water cooling, some oil cooling, and others air. For what you are talking about get one of those cooking torches that they brown the sugar on the top of Creme Brulee. It will be hot enough for what you want. Metal fabrication places have all the scrap metal you could use. Fruehof in Omaha would be a good one to start with.
     
  8. Sparky

    Sparky Member

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    I think I might be able to help you.

    Well - I actually have a little bit of experience in this. The first 4x5 I ever shot with (about 1984) was borrowed from a neighbour. It was a compact-ish monorail with a triangular x-section rail and red bellows (anybody wanna help out on what this might have been??)... at any rate - during the exposing of my third photograph on the camera (a two hour exposure of a twenty-foot high pile of gravel at about 2 am...!), a bunch of yahoos in a pickup truck come TEARING around the corner and actually RUN over the camera, tripod and all. SOMEHOW the camera actually ended up UNDER one of the wheels...!!

    So - to cut a long story short - I opted to get the really beyond repair parts of the camera re-fabricated - that would be the ground glass and the springs.... which SOMEHOW got torn in half. I went up to the engineering shop of the local university and they told me it was a very specific metallurgical blend called, simply, 'spring steel' - and they re-made them for $40. I'm not sure if a waterjet would be the right way to cut them. You should talk to a materials engineer to see if they'd retain the correct properties (might stress the material too much...?).

    http://www.industry.net/industry/file/national/09dvn/psw05.html


    Good luck.
    Jonathan
     
  9. noseoil

    noseoil Member

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    Donald may have hit the best source for you. Band saw blades with the teeth ground off work fine. You can use the raw stock from an old blade, grind off the teeth (cabinet shop, metal shop will have broken blades for nothing) and use a torch on the ends to bend them into shape. If you just heat the ends and use a vice or clamp as a heat sink, the temper will stay in the middle and the ends can be worked hot. I think there is a paste used in gunsmithing which will quench heat traveling in the metal. Try Brownells, they may also have spring stock. tim
     
  10. Aggie

    Aggie Member

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    It's called yellow ochre. Rio Grande Metals tools catalog will have it. They are out of albuquerque NM. Also try a parts catalog called small parts. They may have that exact spring type you want already made. They are really quite reasonable (cheap) on their products.
     
  11. Donald Miller

    Donald Miller Member

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  12. Robert Hall

    Robert Hall Subscriber

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    Aggie,

    Have you been taking "smithy" classes down there in southern Utah? Your not making armor, are you? :wink:
     
  13. Aggie

    Aggie Member

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    Naw spent 3 years taking metal smithing classes at the appalacian Craft center in Tn. It is the art center connected with TN Tech University. Then in SF CA, I went through the Revere Acedemy of Jewelry arts and got certifed as a bench jeweler. A girl has to have a good source of diamonds, and I hate paying retail.
     
  14. Jim Chinn

    Jim Chinn Member

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    Thanks for all the replies. I requested info on a couple of metal working forums and have been told that 301 stainless is a hardened, tempered stainless specifically made for use as springs and items such as metal spatulas and pastry tools. It requires no additional treating for cutting or machining but does require a pretty specific process of heating and cooling to be formed or bent and then retain its qualities as a spring.

    It can be cut on an abrasive water jet or stamped. For aerospace applications water jet is the required method as it introduces no heat into the metal and causes no fatigue at the edges as does stamping.

    I will probably be ordering a 24"x24" sheet of .047" (9 gauge I believe). So if anyone needs such a material in the future for some reason let me know and I can have some cut for you.
     
  15. epatsellis

    epatsellis Member

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    could it be a graphic view, similar to this one?

    graphic view auction

    erie


    Well - I actually have a little bit of experience in this. The first 4x5 I ever shot with (about 1984) was borrowed from a neighbour. It was a compact-ish monorail with a triangular x-section rail and red bellows (anybody wanna help out on what this might have been??)