Calibration of DOC/BT200

Kia ora all, just wanted to ask around as to the methods folk use for calibration of these traps and similar (150/250).

We use a double weight of ~50g and ~120g made from various washers, and make sure the trap doesn’t go off with the 50g, but does with the 120g.

I imagine others do something vaguely similar but thought I’d ask as it pays not to assume!

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According to DOC the trap should not trigger at 50g, but should trigger at 100g.

Page 62

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DOC250 is 50g and 120g.

Aha interesting, thanks Bevan. I may have recalled the wrong numbers - I was there when we made our calibration weights but it was a while ago! Time to get the scales out!

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Always make sure you don’t let it actually hit the treadle (by using a clip). The DoC guy we did a course with had a string with a base weight stainless nut and some others so you could calibrate various weights. Good to engrave the weight on it in them case someone else needs a refresh.

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Hey Tui,

For the DOC200s, use a safety catch then 50g and 100g on a string and gently lower them on to fire at 100g. However, I did note recently that female weasels are typically <100g so if you’re targeting them then you may want to adjust for lower?

I tried calibrating the 250s but it became quite fiddly to get a precise calibration so I just make sure they’re going off above 100g but not much more.

DOC 150/200/250 traps - Predator Free NZ Trust

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@tui_kraal - we are like you and use a weight combination of washers (far cheaper than purchasing actual weights) - we can keep adding washers onto the initial weight until it fires (see picture).
Earlier this year we ordered some new traps and requested that they all fire at between 80-100 gms. We recently caught 2x weasels in a DOC200 (they are now flat fat weasels).

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Hi there. I put a disposable plastic ‘glass’ on kitchen scales then fill it with water to 80 grams, draw a line with a sharpie, fill on to 100 grams and draw another line. The glass and a small bottle of water can be used to check hundreds of Doc 200s before I forget to put the safety clip on first!

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Very nice idea I like it. Only thing is as we are doing this with traps in the bush I think I’ll take washers this time. M12 x 3mm galvanised sort on average 11 grams per washer so about ten seconds each on a linishing belt is enough to get them to ten.

We stuffed an old sock with rags until it had the right weight, and then every time you need to dry-fire the trap for servicing you’ve also checked the calibration.

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