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About this calculator
Type the number off the bag, or choose family, size and level. You get the pilot, the final drill or reamer, the diameter, the metric drill marked as not official, and how to keep the hole square. Where no public document gives a figure, the sheet says so and sends you to the manual.
Runs in your browser. Inches are the official sizes.
Where the figures come from
Solid rivets. FAA-H-8083-31A figure 4-90 gives the pilot and the final drill. A repair rivet (NAS1241, NAS1242) has a shank 1/64 in over nominal, and no public document we found gives its drill, so none is printed.
CherryMAX and CherryLOCK. Cherry prints the drill and the hole limits for nominal and oversize, and offers no second oversize. It prints no pilot: the fraction shown is a working step, the largest of 3/32, 1/8, 5/32, 3/16 and 1/4 in below the final drill.
Hi-Lok, Hi-Lite, Jo-Bolt. The maker's drawings send the hole to NAS618, which is not public. The sheet gives the pin diameter and the fit, and no reamer size.
Metric. On a 0.05 mm step. Solid rivets: the nearest size. Blind rivets: the nearest size that falls inside the maker's hole limits, and the sheet says so; for a 1/8 in CherryMAX, 3.25 mm is 0.1280 in, under the 0.129 in minimum, so it gives 3.30 mm (0.1299 in).
Limits — when NOT to use this
- The manual governs. The SRM or drawing sets the hole. This sheet shows what public documents print, not an approval.
- An oversize is a repair decision. The manual or engineering authorises it, with edge distance, pitch and strength checked.
- A closest family is not an identification. For a number we cannot read, the sheet names the nearest family so you know where to look.
Questions people actually ask
What drill for an oversize 1/8 in rivet?
For a CherryMAX or a bulbed CherryLOCK, #27, 0.144 in, for a hole of .143 to .146 in. For a solid repair rivet, NAS1241 or NAS1242, no public document we found gives a drill: take it from the manual.
Is letter D the oversize drill for 3/16 in?
No. Cherry lists #5, 0.2055 in, for the 3/16 in oversize, in a hole of .205 to .209 in. Letter D is 0.246 in, far above that hole.
Why is the 5/32 in CherryMAX drill different from the solid rivet drill?
Each has its own table. Cherry lists #20 for a .160 to .164 in hole; the FAA table lists #21 for a solid rivet.
What reamer for a Hi-Lok?
The size comes from NAS618, the SRM or the drawing. NAS618 is not public and we found no open table, so we print no figure.
Sources
- FAA-H-8083-31A, AMT Handbook, Airframe, Vol. 1 — fig. 4-90 p. 4-40; pp. 4-15, 4-19, 4-20, 4-51.
- Cherry Aerospace CA-1015 Rev. C and CA-1011 Rev. A — CA-1015 pp. 7, 27; CA-1011 pp. 4, 16.
- Cherry Aerospace CA-1005 Rev. A — pp. 3, 7, 15, 22.
- MIL-R-47196A(MI), 6 Sep 1977 — 3.2.1.1a, 3.4.1 to 3.4.3, Table I.
- Cessna Single Engine SRM 51-40-00, par. 4.A — repair rivets.
- NASA PRC-9007C, Sept 2020 — p. 6, Hi-Lok hole axis.
- Hi-Shear drawings HL18, HL62, HL218 — pin diameters, oversizes, hole preparation per NAS618.