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Bite the bullet and put some tapered pins into the socket

riobison

Well Known Member
I'm going to bite the bullet and put some tapered pins into the Vans socket that goes onto the stinger for the tail wheel to stop the slop.

Where the confusion is that I'm seeing from the B+S # 1 Taper Reamer to the #2 being called for.

As well as the AN386-2-9A tapered pin, AN386-1-8 or the AN386-1-9 being called for.

I don't profess to being a machinist so some of this can be a little confusing without putting some research into it and I have done that.

My bolt holes appear to vary between .19 to .20 id.

My choice:

I've decided to us B&S Tapered Reamer # 1, AN975-3 washer and the Tapered Pin's AN386-1-9

Does anyone see anything wrong with this before I place my order?

If I dull the reamer will I be able to take it to the machine shop to have it sharpened or should I buy 2 of these?

Regular lock nuts or the low profile lock nut?

Thanks

Tim
 
I'm doing this right now, give me 6-7 days and I'll have a better answer when I receive my parts. I originally fit the AN386-1-9A's with a borrowed reamer of unknown origin, the reamer broke on the second hole. I'm not sure the reamer was the proper taper for the AN386 taper pins.

From Aircraft spruce I ordered a #1 reamer as suggested on the AN386 page and a couple AN386-1-7A's for the tailwheel/stinger socket. I found the AN386-1-9A's were about 15/32" too long, if the -7's are too short I'll just trim the 9's.
You could likewise make a #2 reamer and an AN386-2-__ work depending on edge distance between the holes. I also bought AN386-2-9's in case I need to true the holes larger.

I also ordered a #2 reamer and an AN386-2-14 (a little long but half the price of a -13) to replace the stinger/tailwheel bulkhead bolt.

I ordered reamers and pins from McMaster Carr, (the reamers have a different taper) and taper pins to match but forgot to note no threads and will be returning them.
 
Science experiment

Lots of options but I'm thinking unless a guy is a Machinist or at least has a fairly good understanding of this type of work. It could be a science experiment, costly and time consuming in shipping unless a person gets it right the first time.

Maybe some good strong roll pins will work?

In researching from past threads there appears to be part numbers all over the place so it does make me nervous.

Or maybe just buy a new stinger that is machined with a good tight interference fit to a new socket and be done with it?

Tim
 
Here's some relevant info from one of our tech sheets. If you want the whole .pdf file, send a note to me directly and I'll forward them to you.... email me at [email protected]

***************************

To replace the AN4 bolt that hold the WD409 weldment to the the tapered
(stinger) spring:
? AN386-2-9A taper pin (Aircraft spruce)
? AN975-3 taper pin washer (Aircraft spruce)
? B&S #2 taper pin reamer (available for half the price of ACS at http://
www.mscdirect.com/MSCCatLookup2.process?MSCProdID=02054021)
? 12" long tap handle (http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?
itemnumber=45206)
!

The taper pin has the advantage that you can tighten the nut if the pin should
ever loosen up, and things should be snug again. The taper pin is an odd-sized
Browne & Sharpe #2 taper, so don't confuse it with other -2 tapers.
!
To replace the two AN3 bolts that hold the mounting socket to the the tapered
(stinger) spring:
? http://www.aircraftspruce.com/catalog/topages/reamers.php
? http://www.aircraftspruce.com/catalog/hapages/an386taperpin.php
? http://www.aircraftspruce.com/catalog/hapages/an975taperpinwshr.php?
clickkey=61399
!!
You will probably want the B & S Taper No. #1 reamer, qty. 2 of the AN386-1-8
pins, and qty. 2 of the AN975-3 washers. (You can use a longer pin if you like,
and grind off the excess. See ACS notes below for installation data.)
!
You'll also need patience, cutting oil, reamer (tap) handle, AN365-832 or
AN320-832 nuts, and patience.
!!
Pin data from the ACS site:
Manufactured from alloy steel, minimum tensile strength 125,000 PSI. Cadmium
plated. Taper: 0.500"/ft. Use with AN975 taper pin washer, AN320 shear castle
nut and cotter pin or with AN364 elastic stop nut. When installed, the small end of
the tapered shank should protrude no more than 1/16" above the surface of the
assembly. The first dash number is the Brown & Sharpe taper pin reamer number
and the second dash number is the grip length in eighths of an inch. For undrilled
threaded shank add the letter "A" after second dash number
 
Handle and back up?

I'm assuming a standard Tap handle will work?

I'm assuming that the one reamer will be sufficient? I won't need a back up or will I need to have it sharpened after the first cut?

I'm having some CLOSE TOLERANCE BOLT AN173-12 bolts coming that I will try first. Probably won't work for long so I will be prepared with the reamer and tapered pins when that time comes.

These are similar in size to a metric 5 mm bolt and they are tight but being a grade 5 I won't use it.

Thanks

Tim
 
Tim, yes a regular tap handle works just fine with the reamers I got from aircraft spruce. They are plenty sharp enough to do many taper cuts. Vince gave a GREAT post, use his shopping list and you'll be happy.
I have some of the -9 taper pins and they were a tad long, here's a pic of the AN386-1-7A taper pins I installed yesterday which are almost too short. I also over-reamed the holes slightly and used a -4 flat washer to make sure the taper pin didn't bottom out on the taper pin washer.
E7AD712E-A86A-453A-8B07-C4DE52F0374E_zpsqmltvqtp.jpg
 
Tim, yes a regular tap handle works just fine with the reamers I got from aircraft spruce. They are plenty sharp enough to do many taper cuts. Vince gave a GREAT post, use his shopping list and you'll be happy.
I have some of the -9 taper pins and they were a tad long, here's a pic of the AN386-1-7A taper pins I installed yesterday which are almost too short. I also over-reamed the holes slightly and used a -4 flat washer to make sure the taper pin didn't bottom out on the taper pin washer.
E7AD712E-A86A-453A-8B07-C4DE52F0374E_zpsqmltvqtp.jpg
 
Last edited:
Did this on my RV-8

It was long enough ago that I don't remember the specific specs. Vince's post looks like it has everything you need.
Cut slow, by hand, with lots of cutting oil. The materials are soft enough that it is fairly easy to cut. Just buy one reamer. They are expensive. But you could do yours and all your friends airplanes with one reamer.

It is important to alternate the side that the taper goes in on, as shown correctly in the post by Crabandy.

The low profile lock nut is fine, and you can easily cut off the extra thread length.

I was having ongoing issues with bolts loosening in the holes. Installed the taper pins and have never had to touch it again. A must-do in my view.
 
hardware

I've installed taper pins in the tailspring of my RV7. Reading the EXCELLENT post by Vince earlier in this thread, he calls out "AN365-832 or
AN320-832 nuts" for these pins. I ordered those and they seem too small. -1032 nuts seem to fit correctly. Sound correct?

Also, confirming, the "cupped" washer has the larger opening facing away from the nut, correct? Flat washer not needed in addition, unless for thread spacing?

Torque should be about the same as the respective AN3 and AN4 bolts we are replacing?

Thanks!
 
I've installed taper pins in the tailspring of my RV7. Reading the EXCELLENT post by Vince earlier in this thread, he calls out "AN365-832 or
AN320-832 nuts" for these pins. I ordered those and they seem too small. -1032 nuts seem to fit correctly. Sound correct?

Also, confirming, the "cupped" washer has the larger opening facing away from the nut, correct? Flat washer not needed in addition, unless for thread spacing?

Torque should be about the same as the respective AN3 and AN4 bolts we are replacing?

Thanks!

Sean, Don't use the full torque. All you need is enough to hold the pin securely. It's only a shear connection. Some people have mentioned that they tap the pins in to seat them and gently tighten the nuts, and this is what I'll do.

Also, the cupped washer is to clear the pin on that end. The narrow end of the pin pokes out of the hole just a bit (try to minimize that) and the cup washer allows for that.

Dave
 
Sean, Don't use the full torque. All you need is enough to hold the pin securely. It's only a shear connection. Some people have mentioned that they tap the pins in to seat them and gently tighten the nuts, and this is what I'll do.

Also, the cupped washer is to clear the pin on that end. The narrow end of the pin pokes out of the hole just a bit (try to minimize that) and the cup washer allows for that.

Dave

There is a specification for that nut and its less than half of the standard. If you do the wedge calculations for the pin contact stress vs axial load, you will find it is very high. It is an incredible leverage.
 
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