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Reamer vs Drill Bit in pre punched kit?

R

rjtjrt

Well Known Member
I see Claer Air Tools suggest a reamer bit instead of a drill bit in pre punched kit assembly.
Can I elicit any opinions or experience regarding this?
 
I have used both.
Now I tend to grab whichever is closest at hand.
The reamer makes a slightly cleaner hole, but you probably will deburr anyway.

I have not tried the #41 reamer technique which some recommend; it is interesting, but there are 1000's of RVs flying successfully with thousands of #40 holes :)

Thomas
 
I've used a #40 reamer on most of my kit so far. The reamer does seem to make a cleaner/truer hole. A little easier to deburr afterwards also.
 
I use the #41 reamer when match drilling holes. Very little burr, and very smooth, round hole. Some times you have to drill through a punched skin into an unpunched rib, in that case I just use the #40 drill. If you use a reamer, turn it slow, an electric drill works perfect.
 
rjtjrt said:
What is the #41 technique?
JR
Click to expand...

#40 is the actual size for the AN426AD3 rivets. Back in the day, RV guys noticed that once you dimpled the hole for the flush rivet, the hole was slightly enlarged. Said guys then began to use #41 drills to make the holes so that when they were dimpled they wouldn't enlarge so much. I've been drilling my prepunched holes using a #41 drill bit. As has been said, do it which ever way you feel is best.
 
Splitting hairs

Either way...#40 or #41...the hole will be larger than the 3/32" rivet. However, when you set the rivet, the initial axial compression results in radial expansion until the hole is completely filled. Then the shop head begins to form.

The .002" difference between #40 and #41 is splitting hairs.
 
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