Hi

Can anyone tell me how to work out how thick say for example 2-56 pushrods is in metric?

Thanks,

It's around 1.7 mm.

I think 2-56 rod is slightly bigger than 2 mm. Most .40 -.60 size ARF's come with 2 mm push rods and they are a slightly loose fit in 2-56 clevises.

According to my calculations, it's a little more than 2 mm.

The major diameter of a 2-56 rod is about 0.086". Multiply this by 25.4, (the number of mm to an inch), and I get 2.1844 mm. Now remember this is the OUTSIDE diameter of the THREADS. The inside diameter, (the valley), is about 0.065", or 1.651 mm.

So actually, a 2-56 rod should be a little larger than 2 mm.

Thanks, but is there a way to calculate it, or a chart you can work from?

Found this for you http://www.efunda.com/DesignStandard...s/tapdrill.cfm there you can see that #2 is 0.086inch or 2.1844mm and the 56 is how many threads per inch (25,4/56=0.45) so and M2 standard is correct.

the rule is, for the numbers (ie 2-56), multiply the number by 13, and add 60, and the answer is in thousandths. so for instance, a #10 screw would be 190 thousandths (.19) because 10x13=130 +60=190 thousandths. so in your case, it would be 2*13=26 +60=.086 and then you multiply .086 by 25.4 because there's exactly 25.4mm per inch, so you get roughly2.18mm.

I thought 2BFlying just did?

FTR, we have the same problem down here as you probably do in RSA, where virtually everything comes from Asia (ARF) is fitted with metric hardware, and worse, 'Chinese metric' which is somehow consistantly different sizing from Taiwanese or Japanese metric.

Come replacement time for clevises etc, it's a PITA as all the Great Planes and DuBro airplane stuff is 2-56, which as 2BFlying just pointed out, is slightly larger than 2mm which means they're an unacceptably loose fit on the existing 2mm 'metal' rods usually fitted to the various dowl control rods or aileron horns. So instead of just being a simple clevis or snap connector replacement, it becomes a complete control linkage including rods swap-over either at the time of initial assembly or at first airframe & control systems overhaul.

Hi!
What a wonderful world it would be if all countries just could agree on using ....the metric system!

Regards!
Jan K
Sweden

i would have to agree. metric is much better than US standard. good thing we are slowly converting to metric...

jaka,
We have more people, more stuff, and our economy is bigger. So, it would be cheaper if you changed to our measument system . So have at it. [X(]

fwiw, you can buy 2mm hardware from companies like Dubro to replace clevises and such. Nothing wrong with 2mm gear, as long as you don't mix it with 2-56.

Thanks Spaceclam, that's what I was looking for.

Good times.