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Servo arm question....

Old 07-07-2014, 11:39 PM
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time bandit
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Default Servo arm question....

My servo arms have 1/32nd holes in them. My EZ connect head stem that fits through the servo arm is 1/16th in diameter. Should I drill the servo arm hole out 1/16th to accept the stem of of my EZ connect head?
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Old 07-08-2014, 12:09 AM
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JetPlaneFlyer
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Yes, drilling the holes out is often necessary.
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Old 07-08-2014, 12:13 AM
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time bandit
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Originally Posted by JetPlaneFlyer View Post
Yes, drilling the holes out is often necessary.
Thanks JPF. I wasn't sure if it would screw up the motion of the connector in the servo arm by drilling to a larger size.
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Old 07-08-2014, 01:42 AM
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kyleservicetech
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Originally Posted by time bandit View Post
My servo arms have 1/32nd holes in them. My EZ connect head stem that fits through the servo arm is 1/16th in diameter. Should I drill the servo arm hole out 1/16th to accept the stem of of my EZ connect head?

Not the best of quality, but quite sufficient to drill through plastic, aluminum, or the occasional piece of steel.

Those number drills allow very close matching of the hole size required to your pushrod diameter.

http://www.harborfreight.com/60-piec...set-34627.html
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Old 07-08-2014, 02:32 AM
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Heli Jim
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Just don't over size the hole too much. The connection should be snug.
NOT LOOSE!!!
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Old 07-08-2014, 04:41 AM
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solentlife
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I no longer 'drill' servo arms or control horns. I have a sharp point tapered reamer ...

I place arm on a block of wood upside down ... and use the reamer to increase hole to exact size needed .. ream - check - ream - check - ream till it's a nice snug fit.

Why ? The slight taper you get in the hole allows for z-bends to pass through without straining the hole ... the bend in a z-bend needs slightly greater than the rod size. Second many rods are not exact 1mm .. 2mm etc. I have plenty rods that have no drill equivalent ...

Nigel
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Old 07-08-2014, 06:10 AM
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kyleservicetech
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Originally Posted by solentlife View Post
I have plenty rods that have no drill equivalent ...

Nigel
Hi Nigel
Here in the backward USA, we have something called "Number Drills" that come in 60 sizes between 0.040 inches and 0.226 inches.

#60 is 0.040 inches, #59 is 0.041, #58 is 0.042, #57 is 0.044, #56 is 0.046 inches in diameter.

Question, does a similar setup of drill bits also exist in metric sizes?
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Old 07-08-2014, 08:06 AM
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solentlife
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Originally Posted by kyleservicetech View Post
Hi Nigel
Here in the backward USA, we have something called "Number Drills" that come in 60 sizes between 0.040 inches and 0.226 inches.

#60 is 0.040 inches, #59 is 0.041, #58 is 0.042, #57 is 0.044, #56 is 0.046 inches in diameter.

Question, does a similar setup of drill bits also exist in metric sizes?


I'm sure if I was to search out a specialist supplier in Latvia - I could find similar ... but trouble is - Latvia is only a small country with extremely limited need in such field. Shops basically cater for Fred and his simple DIY needs ... if you look at drills - they are the standard 1mm to 10mm packs etc.

In UK ... France .. Germany or whatever is a different matter of course.

With weird sizes - like rods - a short section cut and then applied to grinding wheel can produce a 'spade end' cutter ...

But I still like to point out the benefit of the reamer. Because it slightly tapers the hole - there is more ease to slip the Z bend through without spreading the hole to get that bend through. It's the 90 deg bend that is the concern.
This results in a more close fitted hole to rod.

Nigel
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Old 07-08-2014, 08:32 AM
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JetPlaneFlyer
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My preference is actually ball links. The ball bolts tight onto the horn so no chance of an 'slop', and the link pops over the ball.
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Old 07-08-2014, 08:39 AM
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solentlife
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Originally Posted by JetPlaneFlyer View Post
My preference is actually ball links. The ball bolts tight onto the horn so no chance of an 'slop', and the link pops over the ball.
Yep ... agreed .. but then of course I fly Heli's as well !!

The other of course is the stopper .. where the part is bolted to arm and then rod passes through the hole to be locked by a screw .. another NO-slop arrangement....

One of the niggles are the nylon clevis .. where the ball end is slightly larger than the working part ... so when you press through the hole .. it needs to be slightly larger to let it go through ...

Nigel
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Old 07-08-2014, 10:59 AM
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There are specialist suppliers who can supply drills within .05 of a mm for watchmakers,presumably also in imperial sizes.
You will of course need to be well heeled to pay the prices they charge for such things.But any self-respecting tool outfit should be able to supply jobber drills in .1 mm increments at "normal" prices.
Ok,Nigel,I'm excluding Latvia.
I use 1.7mm bits for 1/16th shafts,or 2.1mm for 2mm bike spokes.
In theory,1/16th is 1.5875mm,but i found a 1.6 mm drill does not allow a 1/16th fitting through.Maybe there is some "spring" in the plastic that accounts for this anomaly.Bike spokes are also varying in quality,and therefore size.
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Old 07-08-2014, 11:25 AM
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solentlife
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The problem with bike spokes here ... they only do down to the 2.2mm size ... none of the 1.5mm and up racing ...

Nigel
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Old 07-08-2014, 12:53 PM
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Yes, tiny drills are available in Number sizes, fraction Imperial, and mini-Metric. I use scrap ply ot plastic (can lids) to test drill for a snug fit, although like jetplaneflyer I do like ball links. Have one plane with EZ connectors but I don't trust them all that well.
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Old 07-09-2014, 12:58 AM
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time bandit
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So I don't want any movement at all by the stem in the servo arm? I tried one hole with a 1/16th drill bit and I could turn the stem fairly easy until I pressed the plastic keeper on from the underside of the servo arm. That got it tight. I've always just made z bends in the past so these are new to me. I did pick up some number drills in our shop today and will try one of those out on the servo arm that I'm testing out.
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Old 07-09-2014, 01:15 AM
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kyleservicetech
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Originally Posted by carpetbagger View Post
Have one plane with EZ connectors but I don't trust them all that well.
Yeah
I've seen two model crashes due to those EZ connectors. They came loose on a glow powered model.

What I've done on the only model in my inventory with those EZ connectors is grind a tiny grove in the pushrod. Then, put the pushrod through the fitting, hit the screw with thin CA, and quickly screw it down. That's pretty much permanent.

Still don't like them. Another club member had an EZ link come loose on his glow engines throttle servo. The engine wound up at 1/3 throttle. To fast to land, not fast enough to fly. The model got damaged while landing at 1/3 throttle.
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Old 07-09-2014, 02:57 AM
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solentlife
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Well - like most things in life ... there's those who have no trouble and others who do ...

I use and like Stoppers for fitting rods ... and have never had any come loose and I do not CA or thread lock any of mine. I grip the body with small pliers and make sure the screw is made up hard.

If I was to use on a glow - and especially on a 4str set-up - I would dab BLUE threadlock in before setting up. But I would not use normal CA..... or RED threadlock.

Nigel
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Old 07-12-2014, 07:30 AM
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I just completed an Airfoilz 540NX
I used Tower Pro 90mg servos.

I do not like to drill out the servo arms

I grind the mushroomed part of the pin in a solder type metal link. Break out the remainder of the pin, then bend a 1/32" wire into a L shape, sand the wire clean, sand the top of the link, use Tinners fluid (very important!!) on the steel parts. Drop the short end of the L through the holes in the link, hold link horizontal and solder to your pushrod and solder the L at the same time. Then clip the short end of the 1/32" wire a little beyond the far side of the link. You can wind the side of the link and the 1/32 wire with tiny copper wire for a stronger bond if you wish. I check the joints as part of my preflights. My pushrods have an adjustable link on the other end.

You can use the wire size to fit your servo arms, these will not bind like some of the micro sized things I have seen.

Yes I could have made a Z bend with my Z bend pliers, but for some reason I wanted to do this for this plane.
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Old 07-12-2014, 12:56 PM
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Yes, 1/32 wire fits my small servos arms snugly. I have simply put a 90 deg bend in the wire end used nylon snap-on keepers (Dubro?), but before hookup I slide a 1/4" or so piece of small surgical tube on the wire and after I snap the keeper in place I slide the tubing over the body of the keeper. Other hookups I have used: 90 deg bend in wire, cut a short piece of wire that extends maybe an 1/8" past the bent wire, attach with heat shrink and weep CA down the shrink.
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