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match drilling the tail spring

Hi All, i just purchased a new tail spring from Fly boy accessories. any recommendations on match drilling the spring? i also have the new socket by JD air.
any advice before i embark is appreciated.
 
Here are a couple of pointers from my build log (RV-7). The jig I talk about was basically an "M" type shape formed out of mild steel angle. The spring rod was held in place using hose clamps at each end. There was a hole pre-drilled at the bottom of the "M" as a guide to ensure that the exit point of the drill would be exactly where I needed it to be on the spring rod (I align with this before I place the rod in the jig. Can't find a picture of the jig right now, but it's somewhere in my shop, so I'll get a pic tonight if I can.

"Drilled the tail wheel spring and WD-409 tail wheel spring mount. Began the process by marking on the WD-409 from the pre punched nut access hole on the F-779 skin. I then transferred this hole position to the other side of the WD-409 by using the parallel sheet of paper method (painters tape also works well). The WD-409 was then placed in my self-centering drill jig that I had previously fabricated and leveled using the digital level, and the top side only of WD-409 was then drilled to 1/8?. The WD-409 was then removed and the tail spring was placed in the jig. This was drilled exactly midway in the machined section. The tail spring was then removed, deburred, then slid into the WD-409, where it was aligned, then drilled all the way through the bottom side of the WD-409 that wasn?t drilled earlier. This hole combination was progressively opened up to D drill size (0.246?). Final reaming has not yet occurred because I only have a 0.249 and 0.250? reamers, and measuring the AN4 bolt dimensions, they are 0.247 to 0.2475? in diameter (the specs say from 0.246 to 0.249?). Thus I will not final ream the holes until I have ordered a 0.247 and a 0.248? reamer."

Cheers,
Tom.
 
I replaced the spring on my rv-4, clamped both springs in between two pieces of angle iron with the old spring on top, using the old spring hole as a drill guide. Aligned and clamped it all up on my drill press and drilled it. It worked perfectly.
 
I need to replace mine next week and I don't have a mill, so I'm wondering if you could elaborate more on the angle iron clamp and using the original spring as a drill guide. How were the angle irons sized/configured? What size drill did you start with and did you ream with or without the jig? Any pictures?
thanks
 
If you don’t want to do it yourself, send your old and new springs to Langair Machining and they will do it for you. They have instructions on their website detailing how they do it for the tapered rod gear.
 
I'd prefer to do it myself to minimize the downtime as it is still flyable, just a little skittish when the tailwheel comes down. I didn't see a jig on the flyboys website and am hoping the old spring can serve that purpose, I have a good drill press, am just not sure on how to clamp the 2 springs together accurately.
 
No drill jigs, but plenty of guides

Hello all, unfortunately we do not have a drilling guide for this job. Drilling to match a pre-drilled mounting socket/yoke to a new tail spring is a little easier than match-drilling a pre-drilled spring to an un-drilled mounting socket. We do have a few instruction sheets that might help guide the process.

Print versions of these instructions should be included with any orders that we send out, but sometimes we miss putting them in the box and it's easy to overlook the documents as part of the invoice.

Digital versions of relevant documents available below, and an online repository of most of our documents can be found here:
- Drilling the tail spring: http://flyboyblog.com/wp-content/uploads/2020/02/Drilling-the-tail-spring.pdf
- Changing a mounting socket: http://flyboyblog.com/wp-content/uploads/2014/08/changing-a-mounting-socket.pdf
 
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