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2018 POTD Thread Archive
- Thread starter 2volts
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- Sep 2, 2013
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Welcome to the wonderful world of hydraulics. Replaced all the hoses on the rear portion of my backhoe a few years back. 12 good sized hoses packed into an incredibly tight area. Had replaced two a few yrs before, and of course it was one of those that was leaking. The others all had 1979 factory tags on them (7k hrs on the machine). Rebuilt the loader valve body and that had mostly solid steel lines which are even more fun. Nice job on the socket. Mike
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- Dec 27, 2014
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A couple of weeks ago my boss, (elder son, runs a model airplane supply) told me he wanted a way of fabricating springs for a gizmo he was offering to his customers. Spring to be made from 36" or .006 music wire. I spent a week or so thinking about it and another week building it. Here it is.
The springs look like this. I used shorter lengths (except the long one) for sampling. The crank on the right turns a 100 tooth gear which engages a 10 tooth gear, spinning the mandrel which pulls the wire through the friction device and around itself. As the spring accumulates it pushes the 'sled' to the left until the entire wire is wound around the mandrel.
Sorry about the focus of the following photo, cheap camera. The coin in the picture is a US quarter. I didn't count the turns but that long spring should have in excess of 130 turns.
The springs look like this. I used shorter lengths (except the long one) for sampling. The crank on the right turns a 100 tooth gear which engages a 10 tooth gear, spinning the mandrel which pulls the wire through the friction device and around itself. As the spring accumulates it pushes the 'sled' to the left until the entire wire is wound around the mandrel.
Sorry about the focus of the following photo, cheap camera. The coin in the picture is a US quarter. I didn't count the turns but that long spring should have in excess of 130 turns.
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- Feb 1, 2015
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If you start with piano wire, it is already spring tempered. No further heat treat necessary.
When the spring is wound, the wire is overstretched, i.e coiled too tightly. When the tension is released, it will spring back, increasing the coil diameter somewhat. Typically, you start with a slightly smaller mandrel so the relaxed diameter meets your requirement.
A refinement is to add a wire guide that fits up close to the mandrel. This prevents the already wound coils from unwinding, requiring less tension on the wire and having less spring-back. This is especially useful when winding heavier gauge springs.
One of the coolest ways to make a spring is to push the wire against an angled block. The wire will form a coil, the diameter determined by the angle of the block. This works great for making conical springs, something that I struggled with winding over a mandrel.
When the spring is wound, the wire is overstretched, i.e coiled too tightly. When the tension is released, it will spring back, increasing the coil diameter somewhat. Typically, you start with a slightly smaller mandrel so the relaxed diameter meets your requirement.
A refinement is to add a wire guide that fits up close to the mandrel. This prevents the already wound coils from unwinding, requiring less tension on the wire and having less spring-back. This is especially useful when winding heavier gauge springs.
One of the coolest ways to make a spring is to push the wire against an angled block. The wire will form a coil, the diameter determined by the angle of the block. This works great for making conical springs, something that I struggled with winding over a mandrel.
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- Dec 5, 2017
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Ah. Thank you. Learn something every day if you're not careful.
So the examples in your post are what I would call "tension springs" rather than "compression springs", yes?
Is the process of making a compression spring similar, just spacing the coils further apart?
So the examples in your post are what I would call "tension springs" rather than "compression springs", yes?
Is the process of making a compression spring similar, just spacing the coils further apart?
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Essentially. You can stretch a close wound spring to make a compression spring. It is usually nor possible to make a tension spring by compressing though. You have to deform the wire beyond its elastic limit to get a permanent deformation and there is always spring-back. When I make compression springs, I will usually close wind them and stretch as require.
It is also possible to wind the spring for a coil pitch other than close with the lathe. This can be done rather precisely using the lead screw to advance the wind. For instance, you could wind two turns close then engage the half nuts for ten turns at a pitch of .1 inches, then disengage the half nuts for the last two turns to give something approximating a store bought compression spring.
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- Dec 5, 2017
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Ah. Again, thanks very much for the lesson. I occasionally need a specific spring for a modeling project and sort through my stash looking for something that's "close enough". I think I'll acquire some piano wire and try a few of my own just as a learning project.