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- Nov 23, 2014
- Messages
- 2,632
I would wind it by manually rotating your chuck, no power feed needed. It's simple to do; if I can do it, anyone can! Rotate the chuck by hand and manually move the carriage as you wrap the wire.
If you were making a compression spring with closed and open coils, I'd wind the closed coils by manually rotating the chuck. Then engage your half-nuts to "thread" the spring on the mandrel. Disengage the half-nuts after you hit your open coil count, then manually turn the chuck to do the ending closed coils.
I attached a photo of Machinery's Handbook spring arbor page. You'll need to do a little development; a 1/4" OD spring made from 0.020" music wire should have a mandrel 0.165" in diameter. I attached some threads of some of the springs I've made and the jig I made for winding them.
A technique for securing the start of the coil on a torsion spring like you need is to drill/tap a hole through the mandrel for a set screw. The start of the spring is trapped under the screw head; let's you stick a leg out before winding. That'd be a pretty tiny screw for a <0.165" mandrel so I don't think that'd work.
A couple of "winging it" alternatives would be clamping the end of the wire to the mandrel with a small clamp. Another is to loosen your chuck and slip the starting leg under one of the jaws. Yeah, the mandrel will turn out of center which might not be a problem. If it is, wrap a loop of wire around the other two jaws so all three jaws are clamping down on the 0.020" wire, that'll center the mandrel. Or, drill a cross-hole like doing an extension or compression spring and manually bend the straight leg after the fact. Your wire at 0.020" bends pretty easily.
Another thing to account for is (pun intended) spring back. Machinery's Handbook mandrel size of 0.165" plus 0.040" of two wire thicknesses is 0.205"; once cut the wire will unwrap on the mandrel and yield a spring ~0.250" OD. This also reduces the number of coils in the tightly wrapped condition vs. the free-state condition.
I did the math on a Bridgeport safety handle torsion spring which worked out pretty close. In your case, (assuming a 1/4" OD instead of 6mm OD spring), here's the math:
0.205" OD (0.165" mandrel plus 2 diameters of 0.020" wire) x pi = 0.644" circumference
0.250" OD x pi = 0.785" circumference
Looks like your spring has 9 full coils:
9 coils of a 0.250" OD spring = 7.07" length (coil length only, not your extended legs)
7.07" length / 0.644" circumference = 11 coils.
I'd start by winding 11 full coils and see where you end up; adjust the number of coils when winding as needed.
Bruce
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If you were making a compression spring with closed and open coils, I'd wind the closed coils by manually rotating the chuck. Then engage your half-nuts to "thread" the spring on the mandrel. Disengage the half-nuts after you hit your open coil count, then manually turn the chuck to do the ending closed coils.
I attached a photo of Machinery's Handbook spring arbor page. You'll need to do a little development; a 1/4" OD spring made from 0.020" music wire should have a mandrel 0.165" in diameter. I attached some threads of some of the springs I've made and the jig I made for winding them.
A technique for securing the start of the coil on a torsion spring like you need is to drill/tap a hole through the mandrel for a set screw. The start of the spring is trapped under the screw head; let's you stick a leg out before winding. That'd be a pretty tiny screw for a <0.165" mandrel so I don't think that'd work.
A couple of "winging it" alternatives would be clamping the end of the wire to the mandrel with a small clamp. Another is to loosen your chuck and slip the starting leg under one of the jaws. Yeah, the mandrel will turn out of center which might not be a problem. If it is, wrap a loop of wire around the other two jaws so all three jaws are clamping down on the 0.020" wire, that'll center the mandrel. Or, drill a cross-hole like doing an extension or compression spring and manually bend the straight leg after the fact. Your wire at 0.020" bends pretty easily.
Another thing to account for is (pun intended) spring back. Machinery's Handbook mandrel size of 0.165" plus 0.040" of two wire thicknesses is 0.205"; once cut the wire will unwrap on the mandrel and yield a spring ~0.250" OD. This also reduces the number of coils in the tightly wrapped condition vs. the free-state condition.
I did the math on a Bridgeport safety handle torsion spring which worked out pretty close. In your case, (assuming a 1/4" OD instead of 6mm OD spring), here's the math:
0.205" OD (0.165" mandrel plus 2 diameters of 0.020" wire) x pi = 0.644" circumference
0.250" OD x pi = 0.785" circumference
Looks like your spring has 9 full coils:
9 coils of a 0.250" OD spring = 7.07" length (coil length only, not your extended legs)
7.07" length / 0.644" circumference = 11 coils.
I'd start by winding 11 full coils and see where you end up; adjust the number of coils when winding as needed.
Bruce
Spring winding jig
POTD was repairing some Erector set parts for sale on eBay. One thing leads to another; I needed some springs and could have gone the finished product route, or wind them myself. I’ve had making a spring-winding jig on my “list of good intentions” for 30+ years. Finally got around to it! I made...
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POTD- PROJECT OF THE DAY: What Did You Make In Your Shop Today?
POTD was done yesterday; ironically “spring time” on the first day of summer. My wife has a coworker who bought a KitchenAid mixer that is missing a spring at the mixing head (for securing attachments). He found a replacement spring on line for $35 and was complaining about the cost. We have the...
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POTD- PROJECT OF THE DAY: What Did You Make In Your Shop Today?
Nice work, is the tool made from a wood dowel? The main body is aluminum. This is the thread on its construction. Bruce https://www.hobby-machinist.com/threads/spring-winding-jig.104748/
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POTD- PROJECT OF THE DAY: What Did You Make In Your Shop Today?
That fixture plate looks great
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