Need some help cutting spring tempered steel! [Archive]

Mat5121

11-Aug-2015, 18:51

Hi folks,

I'm attempting to make some leaf springs for a camera back. I ran a 1/16" sheet of spring steel through the table saw and it ruined the temper. Does anyone here know of an effective way to cut this stuff while keeping the temper?

Thanks in advance for any tips,

Matt

bobm4360

11-Aug-2015, 18:58

Use a cutoff wheel in a mototool or die grinder and cool the metal every 4 to 5 seconds in water. The other way is don't worry about the temper and re-heattreat it afterwards.
YMMV, Bob

vinny

11-Aug-2015, 19:22

If you can't get it to work, buy some .031 stainless feeler guage stock in 12" lengths. No cutting required. I've built two backs with these. Some pics on my site.

MikeH

11-Aug-2015, 21:00

When I worked in a hardware store 40 years ago, we could cut the thinner stuff with sheet metal shears. You might try a cold chisel, with strong safety glasses...

Jody_S

11-Aug-2015, 21:11

I use a pneumatic nibbler.

Jac@stafford.net

11-Aug-2015, 22:36

It is a good idea to put a metal clip on the long side right up close to the cut as a heat-sink even when using a cutting wheel.

Jim C.

12-Aug-2015, 05:49

Holey Moley ! You cut steel spring stock on a table saw !?!

Unless you used an abrasive cutting blade that blade is probably ruined
and you're lucky to have your fingers.

You may try electro chemical machining instead, less nerve wracking,
here's a thread I bookmarked -

http://www.practicalmachinist.com/vb/general/cutting-shim-stock-electrolysis-245768/

Another option is if you have access to a guillotine metal shear.

Mat5121

12-Aug-2015, 09:32

Thanks all for your advice.

Vinny, that feeler gauge stock looks like a great solution! Unfortunately, I planned the back with 3/8" springs in mind and the space is slightly too narrow to accommodate 1/2". I really enjoyed checking out the details on your site btw; that's a nice looking camera!

Jody_S, is it possible to get a nice clean cut with the nibblers?

Jim C., I used one of those thin kerf Diablo steel demon blades with a Gripper block against the fence. It made short work out of my aluminum with a little lubrication and also worked well on the spring stock with a slow feed rate. Too bad the temper was ruined.

Looks like I may have to re-temper but any other ideas are welcome.

Thanks again, Matt

EdSawyer

12-Aug-2015, 10:25

Steel on a table saw is pretty scary sounding to me too, even with an abrasive blade. but it sounds like the diablo used was just a carbide tipped blade? whoa.

I cut aluminum all the time with a carbide blade in a miter saw. no lubrication necessary. It's still a bit scary but spring steel + table saw = way too insane, IMNSHO.

If you have some place near by that does water-jet cutting, that would probably work without losing the temper.

BrianShaw

12-Aug-2015, 11:01

...

Looks like I may have to re-temper but any other ideas are welcome.

...

Yes you may. Its not too difficult, but takes practice to get it right. Make multiple spring blanks while you're cutting metal (safely) so you can temper, test, and then temper another one... until you get it right.

Barry Kirsten

12-Aug-2015, 14:13

The Deardorff store on eBay has back springs and shackles, plus other Deardorff spares. Worth a look.

Mat5121

12-Aug-2015, 15:17

I was consulting Colin Graham's awesome 'Darkshop' blog extensively until it was, sadly, taken down a few days ago. I seem to remember him mentioning those Deardorff springs at some point, and that they were "a joke". I did order a tripod adapter from the ebay store and that was just fine. Anyway, I need odd sized springs because my camera backs aren't traditionally sized: one is 8x8 and the other 10x16. Maybe I should look at other spring options...ideas anyone?

Bob Salomon

12-Aug-2015, 15:21

Carsten Wolff

2-Sep-2015, 04:33

Bamboo is an amazing spring material.

LabRat

2-Sep-2015, 07:52

Or talk to a gunsmith... They make springs all the time...

Steve K

Drew Wiley

2-Sep-2015, 08:26

Table saw??!!!!?? Find a local sheet metal shop that has the correct kind of shears or nibbler. Or just order in cut strips as noted in the previous post. McMaster is
a good source for these.

Mat5121

3-Sep-2015, 10:46

Thanks everyone, and just to follow up here's what happened with the springs: I took Bob's advice and had the steel chopped up at a local fabricator for a small sum. Unfortunately the temper was ruined throughout. I didn't want to reorder from McMaster as it's a PITA for Canadians so I built a small charcoal forge to harden the steel and then tried to temper them on the BBQ, hah! That didn't work out very well so I ended up re-hardening the springs inch by painstaking inch over a butane/propane camping stove and then tempered them by placing on a small sheet of steel suspended over the stove and watching for what I hoped was the correct temper colour. This was sort of a desperate move but it actually worked. Much sanding and polishing later I have some half decent looking, functional leaf springs. Interesting process but "next time" I'll probably start with pre-tempered strips. Carsten's bamboo suggestion could be interesting, although I'd be worried about it splitting.

Regards from British Columbia,
Matt

Leszek Vogt

3-Sep-2015, 12:53

Matt, not sure of what the config is on this item, but I thought that small grinder (4") could accomplish such cutting. The spring has to be in a vice or good sturdy clamp. Sure, one can use a table saw and a metal-cutoff blade (no teeth), but that's convoluting the process, IMO.

Les

Jim C.

3-Sep-2015, 13:22

...... had the steel chopped up at a local fabricator for a small sum. .

Matt5121, I'm at a loss as to how you lost temper if they were cut on a guillotine shear ?

Unless the fabrication shop saw cut them again which would have put you right back where you started.

Drew Wiley

3-Sep-2015, 13:53

Ferrous abrasive metal cutoff blade in a table saw? Someone comes in this store asking to do that, they leave with nothing. Voids the warranty on every table saw I can think of. Not like cutting aluminum (non-ferrous). Nor do I want someone returning with an ambulance-chaser lawyer after they lose an eye or some fingers. I do have German rail saws that accept ferrous carbide, but require a complete anti-static vac line and spark trap system to do it safely. I saw three examples of mini-Chernobyls last year alone where someone tried a shortcut and their containment system melted down into a blob of plastic. Lucky the whole shop didn't burn
down.

William Whitaker

3-Sep-2015, 17:32

Use a cutoff wheel in a mototool or die grinder and cool the metal every 4 to 5 seconds in water. The other way is don't worry about the temper and re-heattreat it afterwards.
YMMV, Bob

+1. I have used this method to cut to length some springs that I had bought from Dick Phillips for more than one ULF camera. I was able to do a neat job with little effort. Just use caution throughout. And wear eye protection!

My 12x20 Folmer & Schwing now has a fully independent rear suspension which is a vast improvement over the 100 y-o brass springs I replaced. But I warmed up my skills with a Korona 12x20 and a shop-built 7x17. Worked like a champ in each case.

Daniel Stone

3-Sep-2015, 18:12

If you have not already purchased material for this project, I'd use multiple layers of thinner material(capable of being cut with metal hand shears), and stack as many "layers" as required to get the desired thickness/spring tension you require.

Tim Meisburger

3-Sep-2015, 23:42

I think you could cut it with a cut-off wheel and a garden hose to keep it cool, but I've never tried it. Handsaw blades are a good source of spring steel.

Vaughn

4-Sep-2015, 08:33

Tim Meisburger

4-Sep-2015, 08:52

Since we are on the subject, I have an old 5x7 camera and the springs have gotten weak. I rebent them by hand and that got them to hold the film holder tighter, but it does not seem like a permanent fix...is there a better way?

If you can bend them to shape they need re-tempering. You can do it yourself or ask a blacksmith or knifesmith.

RichardRitter

4-Sep-2015, 09:22

If the springs are brass the way you harden then is by roll forming, hammering or bending this is call work hardening. To anneal heat to red color and quench in water.

For spring steel to harden heat to cherry red and quench in the right liquid water or oil depend on the type of steel used. then anneal to the proper temperature for the given use of the steel this can be done by watching the color change.To anneal spring steel to the soft stage heat to cherry red and pack in a insulating material and let it cool very slowly or use a temperature controlled oven.

Re-bending a spring will help work harden the spring.

Have you ever taken a paper clip and just kept bending it at the same point until it broke. The spot it broke at is the result of work hardening.

Yes cutting spring steel with an abrasive cut off saw will anneal the steel.

I had a camera come in for repair and the spring were made of old hack saw blades.

Vaughn

4-Sep-2015, 10:00

Thanks...they are brass. I'll try hitting them with a hammer -- perhaps I will take them off the camera first...;)

RichardRitter

4-Sep-2015, 10:44

Vaughn the best thing to do is over bend then with a very nice arc. Keeping the bending point away from the holes. Most leaf spring break at the holes.

Vaughn

4-Sep-2015, 14:59

Vaughn the best thing to do is over bend then with a very nice arc. Keeping the bending point away from the holes. Most leaf spring break at the holes.
Thanks! The springs do have some extra width at the holes -- probably for that reason.

Here is a photo of the camera back and springs -- pretty straight forward set-up. I also have some spare springs (steel) somewhere...hard to know where after a couple of moves, but I had my hands on them relatively recently, so there is hope!.