Supplied Parts Misfit

I was surprised to discover that two parts that Van's instructions say, on page 23-04 of RV-14, Step 3 instructs the builder "To insert Item VA-4908P, threaded rod end, into the end of one of the CS-00013, Bellcrank to Aileron Pushrod."

This is not possible with the material as supplied. Putting a caliper to these items, the following measurements were made:
a) The outside diameter of the smooth end of VA-4908P is 0.427"
b) The inside diameter of the CS-00013 is 0.419"

Van's technical replied to my concern about this by saying to ream it out, though this strikes me as a little beyond the pale, considering these parts are carbon steel, and the difference is 0.08".

Is this typical of technical support, to pass their problems with materials supply on to the customer?

gregfuess said:

a) The outside diameter of the smooth end of VA-4908P is 0.427"
b) The inside diameter of the CS-00013 is 0.419"
Van's technical replied to my concern about this by saying to ream it out, though this strikes me as a little beyond the pale, considering these parts are carbon steel, and the difference is 0.08".

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My calculations shows this to be a .008" delta; Not .080". Big difference.

gregfuess said:

Van's technical replied to my concern about this by saying to ream it out, though this strikes me as a little beyond the pale, considering these parts are carbon steel, and the difference is 0.08".

?

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4130 is a low carbon steel with about the same carbon content as mild steel (.3%). 4140 has a higher carbon content, but Vans uses pretty much 4130 only. It gets it's extra strength from the addition of chromium and molybdenum. It is essentially no harder than mild steel in it's normalized state and therefore easily machined and welded. Pretty easy to remove .008 with an adjustable reamer.

Larry

gregfuess said:

I was surprised to discover that two parts that Van's instructions say, on page 23-04 of RV-14, Step 3 instructs the builder "To insert Item VA-4908P, threaded rod end, into the end of one of the CS-00013, Bellcrank to Aileron Pushrod."

This is not possible with the material as supplied. Putting a caliper to these items, the following measurements were made:
a) The outside diameter of the smooth end of VA-4908P is 0.427"
b) The inside diameter of the CS-00013 is 0.419"

Van's technical replied to my concern about this by saying to ream it out, though this strikes me as a little beyond the pale, considering these parts are carbon steel, and the difference is 0.08".

Is this typical of technical support, to pass their problems with materials supply on to the customer?

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The option, of course, would be to return the materials that were supplied and wait for the original material to become available. We're not passing on problems. Rather, we are working to find good options to keep you building and finishing your airplane. Sorry if you didn't have clear information up-front.

It is entirely and completely possible (and approved by our engineering team after evaluation of the specific material option change) to do this with the materials supplied, and without negative consequences.

Go slow. Steel likes much slower bit speeds than aluminum.

Dave

greghughespdx said:

The option, of course, would be to return the materials that were supplied and wait for the original material to become available.

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Hasn't been offered as an option.

Van's advertises matched hole technology (if the holes match, it must be right!), and can't provide parts that go together as directed in the plans?

I and presumably many others received no notice of a fitment problem, no notice of recommended cures to the problem.

If reaming or drilling is a recommended cure by Van's, please provide the technical advise.

gregfuess said:

Hasn't been offered as an option.

Van's advertises matched hole technology (if the holes match, it must be right!), and can't provide parts that go together as directed in the plans?

I and presumably many others received no notice of a fitment problem, no notice of recommended cures to the problem.

If reaming or drilling is a recommended cure by Van's, please provide the technical advise.

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Reviewing your support case, I see you received the standard tube material rather than the alternative material, and that is was within material tolerances. There are times when it is necessary to remove interfering powder coat material and/or lightly ream or sand parts for fitment. You may sand, ream or drill the inner diameter of the tube if needed, and you may also sand the outer diameter of the part to be inserted, as described in our support team's email earlier today. This is common practice.

Note that tube material ID and OD measurements have ranges of acceptable tolerance. As a result, there are times when a tube's ID or OD needs to have a very slight adjustment made. The tube we use is manufactured in a steel fabrication plant and supplied to Van's. We check materials when we receive them from our suppliers to ensure they meet the range of acceptable measurements. The measurements you have indicated are within the acceptable manufacturing limits. Note that the term "matched-hole" refers to the in-house sheet-metal parts that we punch the holes in on our CNC punch press equipment. Those hills will (and do) line up with each other to a very close tolerance, which creates a self-jigging structure. Steel tube, however, is not matched-hole technology material and it will vary to some small extent, and at times small adjustments such as those indicated here need to be made. This is all part of aircraft construction.

I hope that helps. Feel free to reach out to me or Sterling 1:1 if you'd like to discuss/talk further about this.

If you're this outraged over .008" on a weldment for something you're building in you're garage, God help you if you ever have to work on a Certified airplane. You'll stroke out within the first hour

I received notification that the supplied tube was undersize on the ID and required reaming to the correct diameter. I have a small lathe and a set of reamers so it was no problem for me. The steel machined easy. You could get any machine shop to do this for minimal expense if you do 't trust yourself to do it by hand.

0.008 isn't even in need of a ream. Some sandpaper and elbow grease will take care of the issue. You want a tight fit. I would rather have an interference fit in this area over a slip fit anyway.

WingsOnWheels said:

0.008 isn't even in need of a ream. Some sandpaper and elbow grease will take care of the issue. You want a tight fit. I would rather have an interference fit in this area over a slip fit anyway.

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Yep. I had the same issue….chucked the fitting threads lightly in a drill and ran it against my belt sander. Probably took all of 5 minutes.