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DragonflyAero

Well Known Member
When I ordrered the fuselage kit I deleted the tailwheel assembly, as I intend to go with a Flyboy. What I did not know at the time was that this assembly included the tail wheel spring and tailwheel spring mount, both of which I still need. So I ordered these parts separately from Van's (by the way, the 2 parts cost nearly as was discounted by deleting the whole assembly, so I wouldn't do that again). I received the parts this weekend and was surprised to see that neither the spring nor the mount were drilled for the holes where the spring is bolted to the mount or where the tailwheel is bolted to the spring. I expected to have to drill the mounting holes in the plates where the mount attaches to the bulkheads, but not these others.

Is this correct? I can find no mention of drilling the mount and spring. This is really sturdy steel (especially the spring) and I'm not sure I have the means to drill it. Can anyone help?
 
Same for me Bill,
I deleted the tail wheel assembly then ordered from Vince the spring and everything behind.

I had to order later from Van's the mount.

Nothing is drilled of course...

So I'm putting it off for now and think about it.

Either I'll buy a very good drill guide to do the holes or go to a specialized shop...
 
Call Van's and ask them for the name and number of the person who makes the sprint mount and spring.

Then call them and ask if they will drill the spring to the mount, if you send it back.

I suspect the reason they are not drilled, when bought separately is because they don't know if these parts are going in an older kit or not and if they are, then they need to be drilled to match those older planes.
 
So if received as part of the Assembly they are already drilled? If that is the case I may call Van's and see if I can return the mount and spring for credit and order the assembly at the "kit" price which they credited when I deleted it.
 
Bill R. is correct. There is no way to know on retrofit parts whether there are existing holes to be matched in other parts.

Drilling these holes isn't the same as drilling aluminum, but anyone can do it if they follow the right procedures. Nothing special is needed.

1) use only SHARP bits. A dull bit will turn but not cut properly, often with a loud screech, and cause the parts to work harden. Stop drilling immediately and get a sharp bit. You MUST keep the bit cutting at all times to avoid the screeching and overheating.
2) use cutting oil. Most any oil will work OK if you don't have cutting oil.
3) Use a slow turning drill and plenty of pressure.
4) always drill undersize and step up to the final size after everything is lined up and all undersize holes are drilled.

If you can do the drilling in a drill press or mill, it is easier, but you CAN do it by hand also.

It isn't as difficult as it sounds.

We also have tip sheet on our web site:
tailwheel maintenance and related tips

Drilling tips

In a pinch, any machine shop can do the job quickly. However, consider alignment issues before drilling anything away from the plane. It's not good to have a crooked (not plumb) tailwheel !

For additional questions, email me or call my office. [email protected] or 812-464-1839
 
Good tips Vince. I had the same issue when I ordered the parts. They were easy to drill with my $200 drill press and new bits!
 
Thanks Vince and Andy for your tips and reassuring words !!!

In time, I will surely use those tips and my drill press and share the results here.
 
I decided to use a machine shop to drill the bolt hole through the mount and spring, and will take the spring back to them to drill the tailwheel to the spring. It cost a few bucks but they were dead-perfect in the drill so I am pleased.
 
Bill,

Just make sure that you have identified some way to make certain that the tailwheel will be plumb once you put it back on the plane.

One way to do this, and it's tiny bit of work, but not bad is to install a small set screw into the mounting socket housing. Use the set screw to hold the mounting socket to the tailspring when you set the tailwheel up to be plumb.

You can put the set screw where one of the mounting bolts will go, if it's undersize. Or just pick a suitable, out of the way spot for it. The top front edge of the mounting socket is probably as good as any.

Then pull the parts back off the plane and take them to the machine shop for drilling. Assuming nothing moves, you should have a perfect outcome.

There are other ways, clamps, pins, drill one bolt hole undersize and leave a drill bit in it, etc... lot's of ways to skin a cat.

I've used the set screw technique on gear leg sockets and elsewhere with success too.
 
Now a machine shop, drill press, custom made jig are all ways to drill these holes but before the age when RVs became so plug and play one had to drill the holes in the main gear legs on the -3s, -4s., and -6s and, given the geometry needed to maintain alignment, you pretty much had to do this by hand. Several thousand flying airplanes are offered as proof that mere humans can do this task with a hand drill, some lubricating oil, a few sharp drill bits, and ability to follow directions (Vince's above covers the essentials).

Carry on and don't sweat it. Worst thing that can happen is one work hardens on you. Even that ain't fatal but you will use up a few bits and choice words in recovery. Ask me how I know.
 
AN4 Bolt Hole Reamer Size

Hi All,

I've just finished drilling out my WD-409 and FSTS635-1 tail spring, as they did not come pre drilled from the factory. I've worked my way up to a D size drill, and now I have to ream. Per the advice of the post below, I have a 0.249" reamer, however when I go back and measure the AN4 bolts, they are all around 0.2470" to 0.2475". The specifications on the AN4 bolts are 0.246" to 0.249". Given that this bolt is in a region that will have high vibration loads during taxiing, I suspect that a close tolerance would probably not go astray.
The question I have is, should I purchase a 0.248" ream, or should I just run a my 0.249" tap through and be done with it? I guess I'm concerned about wallowing due to the vibrations and just want to get it right the first time.

http://www.vansairforce.com/community/showthread.php?t=80445

Cheers,

Tom.
 
reamer

The D drill is .246, the hole is probably a bit above that. MSC Supply usually has reamers in .001 size differences. You will get the best fit at this point if you ream in .001 steps. The reamer will stay aligned with the hole much better. Buy a few bolts and measure them accurately. Reaming the hole .0005 undersize works well on the main gear, probably on the tail wheel also. You can also use an expansion reamer but they are very fragile and easy to break. Not sure if they come in sizes as small as 1/4. Some good quality cutting oil helps.
 
Reamer

MSC jumps from .246 to .248 in the online catalog. They probably have .247 in the print catalog or if you call them. I found a .247 with a quick search- just search .247 reamer.
If you buy some bolts from different vendors you can sometimes find variations in diameter that will help in getting a proper fit.
 
Tailspring & socket

Since I was drilling and reaming anyway I just went with the taper pin from the get go.

Don Broussard

RV9 Rebuild in Progress
 
Ok, so it looks like the path to go down is to get a 0.247 and 0.248" remers. I think I'll go down this path and make the fit as tight as possible, then If I have problems down the road, I'll to the tapered pin route.
Whilst I'm in reamer ordering mode, I guess the next question is what sizes to I need for the main gear legs? I have a 0.311", but I'm thinking now I should also get a 0.310". Any suggestions here?

Tom.
 
I measured my gear leg AN5 bolts, and they came in at 0.310", so I guess that means my 0.311 reamer may be on the large side so I'll get a 0.310 just in case. I also measured the AN6 bolts for the firewall, and they were 0.3715", but I am less concerned about these as they are under a different loading scenario.
Tom.
 
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