Return springs for homemade press

[balmerchris]

I've made a press out of some left over channel from work. The jack I have to use in it is 30 kg with 200mm of travel.
It's a very heavy jack but it's all I have.
I bought two springs but they struggle to even hold the weight of the jack never mind pull the ram back in to the body.

Does any one know what spec of spring I would require and where to get them. The calculations are beyond my education.

 

[123hotchef]

do you have a pic of the said press

 

[balmerchris]

Silly of me to start a thread like this without pics. I'll pop out now and get some.

 

[123hotchef]

top man

 

[Rocketman]

It shouldn't be hard to work out all you need to know is the weight at the point it is pushing back and enough pre-tension at that point. Length you never want to go solid on a spring when it's compressed so many manufacturers give say a 60% compression point.

I have loads of catalogues here with springs in, used loads over the years say for slider returns on tool designs.

Online something easy to look I would guess maybe misumi?

If you're stuck I can probably get some pics up of stuff you can probably then order online.

 

[balmerchris]

4 and a half inch flap disc for scale.

 

[123hotchef]

nice, proper press, yes those springs will never be man enough for that i bet that jack and x member weight 15-20kg

 

[balmerchris]

The jack alone is 30 kg the channel it's on is about 6kg but I'm thinking of making it out of something lighter.

 

[123hotchef]

nah dont do that just get the right springs

 

[balmerchris]

It shouldn't be hard to work out all you need to know is the weight at the point it is pushing back and enough pre-tension at that point. Length you never want to go solid on a spring when it's compressed so many manufacturers give say a 60% compression point.

I have loads of catalogues here with springs in, used loads over the years say for slider returns on tool designs.

Online something easy to look I would guess maybe misumi?

If you're stuck I can probably get some pics up of stuff you can probably then order online.

How would I work out the weight going back in?

 

[123hotchef]

they look like camp bead springs

 

[ukracer]

The jack alone is 30 kg the channel it's on is about 6kg but I'm thinking of making it out of something lighter.

It will end up bending then>>

 

[balmerchris]

they look like camp bead springs

Yeah similar. They seemed bigger when I ordered them.

 

[123hotchef]

Yeah similar. They seemed bigger when I ordered them.

I hate it when that happens!

 

[Screwdriver]

If you have the room, rig up some counterweights attached by cable to a couple of pulley wheels. Then you can use more reasonably size springs. You can run the weight(s) inside a length of plastic pipe to keep things tidy.

 

[the snooper]

ive seen people make them with the jack mounted upside down on the top rail, if you did that you may have to alter the jack a little and fit a reservoir to enable the jack to work but then you wouldn't need to raise the weight of the jack

 

[Bsmith]

Garage up and over door springs?

 

[Turbo]

As said, use springs off a busted trampoline. If 2 aren't enough add 2 more. I've a large bucket full of them from 2 trampolines & you're welcome to a few of them for the cost of the postage!

 

[8ob]

There is a nice wide platform either side of the jack so you could anchor down a pair of road springs off a car or motorcycle , they will work in tension and compression. Just thoughts.


Bob

 

[mike os]

Mine is very similar... I used 4 trampoline springs... maybe just add more?