Quick Tip #2: drilling servo arms to fit your pushrods
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- Опубліковано 30 вер 2024
- It's very common for the wire used for pushrods on ARF or PNF RC planes to be too big to fit through the holes on your servo arms. You could find a suitably sized drill bit but it's much easier to simply use the pushrod wire itself as the drill. Quick, easy and a guaranteed 100% perfect fit.
I often 'drill' with the wire as is, pressing really hard like a neanderthal for about five minutes, usually works. At the end I am rewarded with a strange sense of satisfaction that my stubborn persistence won over, and I triumphantly give the servo arm the finger and say "gotcha bitch".
iforce2d
That's my method too. Then I think of at least 3 other ways of doing it that would have been easier.
the only thing I do not like about this method and Bruce's is the fit is too tight. I like the fit to be such that the arm almost freely spins on the wire with no slack. If you get it too tight it can put a small amount of load on the servo and make it harder to center properly.
Snip off the end of the Z bend at 45°.
All these tips from the '70s.
Tears to the eyes don't you know.
Another way - take hobby knife, insert it perpendicular to hole, twist 5 times, repeat from another side. And you have your bigger hole in 30seconds.
I take a old blade in an xacto knife and twist the blade in the hole
Just heat them up and push them through for a perfect snug fit. Grinder FFS!
I just hold the push rod with pliers and use a match to heat it for about 5 seconds. Then you just push it through the servo arm like a hot knife through butter. Works every time and takes 5 seconds.
Good idea, Bruce. I used to enlarge pushrod holes by twiddling them out with an X-acto #11, but later picked up a couple of pin vises at the local hobby shop, each containing an assortment of small drills, and have been using those since. Not as cheap as sharpening the pushwire certainly, but still mere pocket change. Plus, I'd need to move several airplanes to get to my grinder bench... ;-). Cheers.
Use a Bic lighter, Just heat up the push rod and push it thru... Done..
$2 drill bit. $120 grinder. Hmmmm?
$2 or $120 hmmmmm. . . .
I know. Heat the wire and melt a hole.
Use a 30USD dremel instead.
$2 drill bit needs a $20-120 drill.. (Ok, so you can wrap some thermoshrink around the bit and use it by hand..)
Or maybe a nice file? Something that you should have on hand anyway. A few quick licks and same result.
was just about to comment this...
ElectraFanfure: I use a pin vice with 4 different sized collats to hold my little drills. $3.71 NZ with free shipping from BG.
Electric tools not required.
You guys are thinking too rich.....
$5 pair of side cutters.
single diagonal/taper cut. there's your drill bit.
then you can just use the side cutters to make a straight cut to get rid of the taper. this will mushroom the wire a little which will make it a little harder for the horn to fall off.
Good tip Bruce, but I can't say I approve of your technique with the grinding wheel, if that wire digs in to your wheel your going to get hurt. It should be a trailing-edge if your just holding it at an angle but really you should adjust the rest to get the right angle and use that. I know, but I used to teach kids to use this stuff.
I did exactly that back in the mid eighties. Wire wound around wheel, and diced open my index finger knuckle. Still hurts today.
Looks a bit too tight... but good idea in a pinch.
Yeah I'd invest in a set of drill bits before a large grinder to solve that problem.
HINT: Stainless Steel 308 TIG Welding Rod 0.045"x36" | Pack of 1-Lb = cheap 1.2MM push rods that won't rust. For the hole, Cut a 3" piece, heat with a butane lighter for 10 secs and insert through the horn opening you wish to enlarge. Trim excess melted material with x-acto knife flush to the horn.
I just heat the wire and melt it through the nylon Horn
heat wire for 5 seconds with cigarette lighter or candle, poke through. clean daggy bits away with excto or similar. no grinder required. exacto optional, any sharp implement will do.
Wow, that was good and simple... Nice work Bruce!
I use a Turnigy reamer,great piece of kit. hobbyking.com/en_us/knife-edge-reamer-3-14mm-holesize.html
I find grinding takes the temper out of the metal,so grind quickly but let it cool . just putting a quick flat on the end of the wire does work like you said. DO NOT attempt to grind down the diameter of the rod ,then try to bend it with a Z bend,the rod will be junk.I tryed that the very first time I was making a foamy plane. learned that lesson quick I did. lol. Nice tip there Bruce.
well I have a wood/metal shop full of tools I have 3 grinders set up of different jobs but I also have lots of sets of drill bits :) I have also used the wire drill trick using a cut end of a wire, fast and easy.
Here is another bit of advice. Invest in a set of numbered drill bits. The reason being is the size between bits if very small and allows adjustment from one size hole to another without making large jumps. They can be used on servo holes and many more applications where you want a fairly precise fit. I have even used them to alter airflow in carburators that do not perform well through their entire range. These bits can be used to estimate sizes of holes that you cannot fit calipers into as well. So many uses. I wish I had them 20 years ago as it would have made many tasks much easier.
Let me say that holding the servo wire the other way, so that it's pointing in the same direction as the surface of the grind wheel is spinning is safer and works just fine..
You can also do this with a file but it takes a bit longer. Just hold the servo wire down on a piece of wood and hold your file at a bit of an angle as you file one side then the other.
I've even used the file on my Swiss Army knife.
Wet and dry or sand paper can do it too, Hold the sand paper/wet or dry paper down on a hard flat surface and rub the servo wire from side to side at an angle. but be prepared to wreck the paper if you press too hard.
Or you can even use your sister's nail files/emery boards, whatever.
Not as convenient as a grinder, but who's got one of those?
Actually I have a mini drill with little grinding wheels, so I use those.
A pin vise and correct size drill then draw the drill out without it turning to ream the hole and you can work at the kitchen table and not need a workshop. (sorry, nothing meant against your tip)
Not that good of an idea, next time you rub your skin against that rod and let the bleeding begin, don't do it.
Just use a lighter or candle and heat the wire to punch thru the hole, cost you nothing and is much safer for the future on the field.
I do the same by cutting the wire using a wire cutter plier. You get the same bevel edge and it is cold worked as well. Just remove the burrs on the side of the bevel with sandpaper or a file.
Flic your Bic for just a second or two, goes right through, and no sharp chisel point to catch on later....
If you get the hole too big, just install the servo wire and add a single drop of superglue where the wire goes through the hole. Let it set naturally, then move the wire around and it will loosen and be fine.
I usually use a lighter to heat up the pushrod, and then push it to the servo arm. Dont heat it up too long. Otherwise the hole will melt and wont have a good fit with the pushrod.
I often just snip the end of the control link with a pair of pliers or side cutters , be it piano wire, mig welding wire or what may come with a kit. doing so gives a similar chisel point that will allow to do a similar process.
I do it with a nail scissors. :D works the same, but everyone has a nail scissors ;)
and pop a blob of hot glue on the sharpened end before you slash ya self moving the model around 😊
I don't have I grinder so I just use a candle lighter, heat up the push rod till it glows red, push through the old hole, job done!
using a lighter is even simpler. just heat up the Z bend, push it through the nylon hole and let it melt through
heat a small screwdriver or nail etc and poke it threw the hole...
I have often heated up the rod a bit until it softens up the nylon a bit and it pushes right through with ease.
Hotting the end up with a lighter and poking it through is easier .
Picked up a small pin drill; works wonders.
I've been using Torx bits, twist the hole out.
Will it grind
More will it grind
Can of lemonade
Thickness of this pushroad???
i heat the wire and it goes through easily
a Swiss army knive will do any time
A small needle file can do the same.
Simple y eficaz
Just use a box cutter
now that is smart, thanx
Good tip Bruce! After reading the comments I found many of them useful. I think I'll try this method and the heat method and see which one works best ;-) I'll be using a file as I don't have a grinder. Happy Flying!
Brilliant
Nice ! I already have every drill bit size I could ever possibly need and 3 grinders. What I don't like about drilling is reducing the thickness of the arm as much as I've had to do and/or creating too much play. I will be definitely be using your tip from now on. Thanks Bruce. P.S. you should have grinded from above or the side, not below. I'm waiting for a blooper reel of a pushrod sticking out of your shoe ;)
As mentioned before, snipping a waste piece of piano wire with nice sharp side cutters will put enough of a bevel on the tip to drill out the hole. Heating can make the bend brittle in some cases so I tend to avoid that method. Also a Dremel disk is also great for the job if you haven't got access to a grinding wheel. Excellent work as always Bruce!
Hello, Bruce! I find more easy to use a high pressure lighter, especially in the field, heating the other side of the pushroad, passing for a second thru control horn, clean it with a exacto knife and that's it. Works great!
I use the metal rod to heat it up and melt a hole. I refrain from leaving sharp edges on my planes. A zip-tie cut too long can cut skin pretty good too.
Thanks Bruce. You should probably make these little tips videos part of a playlist/series.
I love my grinder, absolutely essential.
Neat tip, thank you. Btw my new favorite UA-cam channel is xjet. I laugh so hard at you busting your buddy Bruce. Hilarious
Errr not Bruce ... your buddy Ron
I heat mine on the stove and melt my way through!
1st
A quick tip- just the tip mind you, and only for a minute...