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Brake mount and gear hole

D

ddnebert

Well Known Member
Page 46-4 Figure 3 shows drilling the brake mount through the main gear leg axle and optimistically says 'insert a 3/8" drill bit through the assembly and final drill the smaller hole.' In my case, a 3/8" drill bit will not fit in the axle and it is very hard to try to use the drill bit to enlarge the hole through all that steel. The one hole in the U-1003 bracket is 3/8" already, as advertised.

What are others' experience here? Is it just too cold in the garage and things are smaller than they should be, or is the leg axle hole undersized? Should I blow-torch the gear leg? :rolleyes:

Doug.
 
Doug,

Vans saying "insert" is like the doctor saying a kidney stone causes discomfort!:eek: I don't recall drilling the axle to final size that tough. If I recall I didn't use the flange as a guide until the last pass. I do recall using a smaller bit before using the 3/8". I have a numbered drill index and just worked it up one size at a time. It would be pretty difficult to get off track drilling through that material. Hope it helps.
 
I've got no memory but I think I used a 3/8" reamer and then a drill to enlarge the other mount hole.
 
3/8" is specified

The instructions make it sound like the axle hole and one side of the mount is to size (mount is) and that the other side of the mount needs to be match-drilled. I found one weblog reference to someone who used a $12 reaming bit from Cleaveland Tools, but I wondered if this was normal having seen no other chatter about this in the lists...

I tried a torch on the axle and didn't get anything more than the threads in the axle. It'd take me 30 mins of solid work and a workout on the compressor or electric drill to make the bolt fit in each. That's not right.

Doug.
 
John
I said I didn't have a good memory. The 7.9 mm bit is what I used now that you mention it. Sorry Doug, thanks John.
 
I'm pretty sure the steel is heat treated. I don't think I'd get anywhere near it with a torch; especially on a main gear leg. I'd call Vans to check but I would bet that's a big no-no from their perspective. The gear need to have a certain about of spring in it. If it's too brittle well... :confused:

Looking at the plans, they call for a 7.9mm hole (for an AN-5) bolt through the landing gear mount and gear leg.

But where the brake mount is it calls for a 3/8" hole. Even though it's still and AN-5.
 
Need a 3/8 hole for an AN6 bolt

According to Figure 5 on page 46-4, the hole called out in Fig 3 to be drilled to 3/8" will host an AN6-23A bolt, not an AN5.

brake_mount.gif


I am consulting with Vans, it seems my situation is somewhat unique.
 
Ron B. said:
John
I said I didn't have a good memory. The 7.9 mm bit is what I used now that you mention it. Sorry Doug, thanks John.
Click to expand...

You're close!! The 7.9 mm bit is used on the gear leg box to upper gear leg bolt. Doug, what size hole is in the axle? Possibly it only has a small pilot hole instead of a slightly undersize hole from the factory? You could give Van's a call,:rolleyes: don't heat it though, just lots of cutting oil and work your way up to 3/8"
 
Yes I know , I was on the wrong end as usual.But this makes my first responce correct!!!
 
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Your right. Mine shows and AN-6 too....

I don't know WHERE I got AN-5 from. And I even looked at the plans before I typed, but didn't check close enough apparently.

And yeah, mine definitely shows a 3/8" hole.
 
make it bigger

Tech support folks at Vans said they went and checked a bunch of gear legs in storage and the 3/8 bolt fit in all of them. They won't replace the legs and cover shipping and told me to enlarge the lower holes with a fluted reamer. So, I ordered such a reamer bit from Cleaveland Tool.
 
That's a good thing to watch out for going forward....

Did they say anything about that metal being heat treated??? I'm pretty sure it is, but not 100% certain.
 
No mention of it being heat-treated, but I would assume that the gear leg is tempered steel. The drill bit sure didn't like it... Tough stuff.

Here is what Vans' response was:

"The manufacturing spec calls for the holes to be .373-.375, which means it will be tight on a 3/8 bit, but a AN6 bolt will be a slip fit. This is exactly what I've found testing several gear legs here. The specs and manufacturing techniques haven't changed in the last five years. We have to make the hole this size because the bolts run .001-.003 small, but never large.

There isn't any point in returning them. You can successfully ream or drill the hole the tiny bit you'll need to fit the bolt. One trick I've found useful is to dull the flutes of a 3/8 bit on the Scotchbrite wheel, but leave the cutting edges at the tip sharp. With the gear leg clamped securely and plenty of cutting lube, the bit will cut the collar without damaging the gear leg."

Guess we'll close this thread, unless I have fits with the reamer...
 
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