Reamers and RV Tool Kits

[az_gila]

Working with a RV-8 builder this weekend, we had trouble inserting the AN3 hinge bolts in his ailerons.

I knew that he had reamed the holes, and found he used a 3/16 reamer which was provided in an RV tool kit he had purchased used.

Some sizes...

AN3 - 0.189 max. diam. - ream #12 - which is also 0.189

A 3/16 reamer is 0.1875 - and that 0.0015 does make a difference!

So check your reamer sizes, and buy a #12 one for your AN3 bolts if your RV Tool Kit was shipped with a 3/16 one.

The tolerance on AN3 bolts is .003 total, so perhaps half of the AN3 bolts you have will be a slip fit into a 3/16 reamed hole...

gil A

 

[SvingenB]

I am going to order some reamers. For the most common bolts, which drill - reamer pair are OK or preferable?

 

[az_gila]

Sizes...

I am going to order some reamers. For the most common bolts, which drill - reamer pair are OK or preferable?

From an old posting...

A NAS #8 screw is 0.1635 max. diameter, so a #19 reamer at 0.1660 is a better choice.

At #6 size, the screws get to be non-structural and commercial standards apply, the #6 screw has a nominal diameter of 0.138, so the #28 is a good close fit at 0.1405

To get to the larger AN sizes...

AN3 - 0.189 max. diam. - ream #12 - which is also 0.189

AN4 - 0.249 max. diam. - ream 1/4 or letter E at 0.250

Drill a few thousands undersize... usually, the next highest number (or lower letter) in the drill set...

A drill size chart is here...

http://www.csgnetwork.com/drillsizeconvert.html

gil A

 

[SvingenB]

Thanks, they are now ordered