Springs for DIY drill press

[composition4]

Hi,

I'm in the process of making a sturdy, high RPM, cheap PCB drill press for use with carbide bits (will post plans and tutorial when I'm done, within a week or two).

I'm having trouble sourcing a couple of small extension (tension) springs, which are to return the drill head after it drills the hole.  I could buy some but they are $5 each for a tiny tiny spring, and this doesn't keep with the cheap part of things.

Can anyone think of a good source to salvage a couple of springs?  I was thinking along the lines of a retractable ballpoint pen, but that won't work because the springs are of the compression type (opposite ends of spring designed to be pushed together, not pulled apart)?  And an old VCR/cassette player isn't an option as I don't have any and I doubt it would be a common thing for others building once I publish the plans...

Thanks
Jonathan

[markeebee]

Rubber band?

[composition4]

I thought of that but it somehow seems a little dodgy to me... not sure why.  Would have to be a couple of really thin rubber bands I guess as I don't want the return tension to be very high at all.  I'd prefer to find a source for a small long spring though.

Thanks for the suggestion! If there really is no source for a cheap suitable spring I may go with that.

Anyone else have any ideas?

[Top Top]

The hardware store around here has two packs of the types of springs you are looking for for around $5. Maybe just check another hardware store.

[composition4]

Sorry, I should mention that I'm in Australia...

[Tony Forestiere]

If you could find an old typewriter that has a movable platen (carriage), there is a long (12 inches or so), small diameter tension spring that sets the tab stops. Smith-Corona, Royal, etc.

[composition4]

Thanks,

the drill press is relatively small so I would be looking at 2 - 3 inches in length, not 12... I guess the springs could be cut though!

Keep 'em coming, appreciate the suggestions thus far.  Just trying to think of a common item with springs that the average Joe wouldn't have any trouble finding

Jonathan

[composition4]

Hm, just had a thought... maybe the spring used as the strain relief on guitar cable plugs...

EDIT: Or actually maybe not, they are probably too strong due to the thickness... which would mean I'd have to press down on the drill harder to overcome the tension... and the harder you press, the less control.  Realistically I want it to be *just* tense enough that the drill will return upwards and it would only take light pressure down to lower the drill head.

[trjones1]

Why not springs out of a ballpoint pen?  Too weak?  Or try the spring in a Bic lighter that presses the flint against the striker wheel.

[Ben N]

Maybe TOO small, but  vaguely recall having pulled tiny springs out of an old hard drive whilst disembowling it.

[composition4]

Ballpoint pens work by compressing the spring, not by expanding (pulling) it.  The spring in its "rest" state has gaps in it and isn't designed to be pulled, but pushed.  Just doesn't seem that it'd work well at all.

A hard drive you think Ben?  Hmmm, I wonder how small the springs are...

[Paul Marossy]

I've seen springs about 1" long at the local hardware store the other day. They were the kind with a loop at both ends. They were pretty stout, though. Might be too strong for the job...

[Jarno]

How much travel do you need? Are leaf springs an option?

[composition4]

The more I think about it, the more that the rubber band/elastic solution appeals to me... I think it would be easier to get the tension right.  In particular, I'm thinking of that round elastic string you get (kinda like a round shoelace but elastic).  Tie that around screw on the drill stand stationary "arm", then tie the other end to a screw next to the drill head that is meant to slide up/down.

I guess what I'm saying might not make sense... for perspective it will be similar to the press here: http://www.instructables.com/id/%2430-High-Speed-PCB-Drill-Press/step5/Finishing-Thoughts/

except with parts that are a little easier to obtain here in Aus.

I wonder where they got their springs from...

[composition4]

I wonder if these would work:

http://cgi.ebay.com.au/Aplus-Exhaust-Header-Springs_W0QQitemZ220519588148QQcmdZViewItemQQptZRadio_Control_Parts_Accessories?hash=item3357fde134

They are meant to be for radio control cars... 90mm long which would be fine.  Does anyone here have any experience with RC cars?  How much tension do these springs have? Hopefully not too much...

Jonathan

[starekase502]

tell me what size and about what specs you need and i can send you a few for just cost of shipping.  at my work we have a stock pile of all types of srings that  were free to grab a  couple out of.  i just cant get carried away

[composition4]

Hey thanks heaps for the offer, much appreciated.  I actually bought a set off eBay for a few dollars, so won't be required.

Will do the write-up on building it after I'm done

Thanks again
Jonathan

[markeebee]

Dang!  I was going to offer you the springs I took off my strat trem.

[robmdall]

I was going to suggest a Bungie cord / tie-down. I use em' for everything...

[composition4]

The unit is very much nearly finished... In fact it was but then I made a stupid mistake and burnt out the laser-sighting diode (6V PSU wasn't regulated, thought it was!)

Should receive the new laser either tomorrow or Monday.

I will post a write-up with pics if anyone is interested... let me know.

Thanks
Jonathan