conical compression spring

I'm on a snipe hunt for a special compression spring. it needs to be conical with the large end OD around 0.390" or a bit smaller (like
3/8) and a small end OD of 1/4" or a bit smaller. When the spring is compressed to 0.225" high it needs to push 8 - 10 lbs. force. Similar straight compression springs have 6 coils of 0.028" music wire and constant of 25 lb./in.
I've been trying on line catalogs with no joy, so far. Anybody suggest a good source to try?
Karl
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wrote:

I made a compression spring at the beginning of the month. In fact I made several before I got it right. There are some good web sites with information. So if you can't find one already made, you can make one yourself.
I used the lathe, but turned the spindle by hand as my lathe will only go down to 4 threads per inch and I needed about 2 turns per inch. So turned the spindle a half turn and then moved the carriage a quarter inch and repeat. It came out surprisingly well. The reason I had to make several was to get the mandrel the right size so the finished spring was the necessary diameter. i ended up making the mandrel out of oak from a pallet . .750 was too big and .625 vas too small so the metal rods i had on hand would not work.
Dan
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-I made a compression spring at the beginning of the month. In fact I -made several before I got it right. There are some good web sites -with information. So if you can't find one already made, you can make -one yourself... -Dan
My 10" South Bend has enough back-gear torque to wind 1/8" SS TIG rod into conical spiral wood stove handles, on a steel mandrel threaded 4 TPI with a half-round bit.
There is a traditional clock part called a "fusee" which is similar to the mandrel for winding a conical spring:
http://upload.wikimedia.org/wikipedia/commons/1/11/Fusee_With_Cord.png
jsw
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My lathe has enough torque in back gear and with the VFD it can be very slow. But no easy way to get 2 tpi.
Many years ago a friend and I made springs out of quartz. It takes a little experimentation . We used a quartz mandrel about 12 mm in diameter. The quartz being wound was about 0.5 mm in diameter. You have to heat the quartz being would with a oxy- acet. torch enough to soften it , but not so much that it sticks to the mandrel. We used power feed on a little Craftsman 6 inch lathe and about 8 tpi .
Dan
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On 23/04/13 14:18, Jim Wilkins wrote:

I was wondering about doing that recently for a similar application but when I looked my local farm supply had chipping hammers with coil spring handles for 1.70 UKP (about $2.60) so just bought one and cut the head off and welded it where required.

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The stainless wire door handle doesn't feel hot in a location where previous wood handles slowly carbonized. jsw
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On Tuesday, April 23, 2013 9:18:18 AM UTC-4, Jim Wilkins wrote:

Hi,
Interestingly, a Fusee is a "thread" following a hyperbola, not just a tapered thread. They are a bit more difficult to make.
I have written a program to CNC a Fusee on a lathe. Quite surprised myself with that one.
--

PaulS

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    It sounds like a custom spring. How many do you need? If enough (thousands at a guess), contact a maker of springs and ask them for a quote.
    If on the order of 20 to 100, set up to turn them on your lathe.
    Here is an excellent resource on how to make springs. I don't remember anything in it about conical springs, but I would turn up a tapered mandrel and wind the springs on that. Perhaps a tapered thread on the mandrel to guide the spacing of the wire.
    Is the taper in this to allow the spring to compress to a flat spiral at maximum compression?
    Good Luck,         DoN.
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The usual use for a conical spring is because they can be compressed down to a much shorter height ( IE one that's made .028 wire can be compressed to a height of appx .028)
In contrast, a straight compression spring made with the same diameter wire will take up .028 on each end amd another .028 for each turn.
All of which makes me wonder why you are wanting a conical spring if you are only compressing it to .225 height

I go through about 500 springs per month, ordering from "custom spring products" in Hillsboro, Oregon.
Suggest call-they might have something in stock....
http://www.custom-spring.com/
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Karl Townsend wrote:

Contact spring from a flashlight battery clip maybe?
http://www.reidsupply.com/products/tooling-components/springs/compression-spring-music-wire/conical-compression-springs/
http://home.earthlink.net/~bazillion/types.html
--
Steve W.

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On Monday, April 22, 2013 4:50:37 PM UTC-7, Karl Townsend wrote:

Well, the stainless springs in Delta faucet seal kits are about that size. They're a bit light on the force side, though.
You can often stack Belleville washers (adding them in parallel for higher force, or in series for lower) to get a target stiffness. They're conical, but not as extreme as your description (nearly flat disks). Four McMaster-Carr     9712K58 in series would be about right.
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wrote:

Some single-control faucets used such springs, replaced valve spindles with them a whole bunch of times at the parents' place.
Stan
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On Mon, 22 Apr 2013 18:50:37 -0500, Karl Townsend

Thanks everybody for all the tips. I had posted this request on several sites. Turns out another guy needed the EXACT same spring and had it custom made. he's GIVING me a couple.
Karl
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