copyright Tom French, W1IMQ
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Our home page is artifaxbooks.com
The McElroy home page is here.
Last updated May 2009
This list does not contain every Mac-Key serial number; just all of those I am aware of. It is based on over twenty years of collecting McElroy bugs (Mac-Keys) and accumulating information on the keys owned by others, or seen in various places (hamfests and eBay, for example). It updates and expands the list at Appendix E of my McElroy book (see this page for information on the book).
The quantity of keys listed in each group give a good idea of the relative scarcity of the models and variations. The list may also be used to identify your Mac-Key model by using its nameplate type and material, base finish, and serial number, and comparing them to those on the list, but your key should also be verified by comparison to the photos.
The various key models are illustrated in photographs on the Mac-Key page link given here.
I have incompete information on those models missing a variation letter (1936, 1938), so these may not be in their correct sequence.
Please read the NOTES at the bottom of the page. These will explain some differences and the variations in the bugs.
Nameplate styles The "small" plate says "T.R. McElroy." The Navy plate is self-evident. The "large" plate says "Theodore R. McElroy." The plate used on the late bugs (P-500, A-400 and Streamspeed) has no serial number; so these models are not listed. For pictures of the bugs and nameplates, see the Mac-Key page (referenced above).
A caution to collectors. All of the 1934, 35 and 36 models say "9-34" in the cast legend on the bottom of the base. This leads some to think that a 1936 model, for example, is a 1934 model. These bugs can only be differentiated by their design, plate material or (using the list below) serial number.
If your key does not appear here, or to correct a listing, please submit the following information (see home page for mail or email addresses):
..model, or better: photographs of the top, pivot, and left side of the bug.
..nameplate type (and material, if early small plate)
..serial number
..any other information, see list for examples
small brass plate
model SN comments
1934 5401 possibly... (hard to read) see ad QST Dec 1934 p. 88
1934 5406 Warren K2UVV
1934 5450
1935 5402 shallow vee; GAD
1935 5515 shallow vee; GAD longitudinal plate facing left (Doug Palmer via ebay 10/08)
1935 5517 shallow vee; GAD longitudinal plate facing left. (eBay 2/07)
1935 5535 Shallow Vee, GAD
1935 5548 Shallow Vee, GAD
1935 5555 shallow vee, GAD (info de Fred KT5X)
1935 5587 shallow vee, GAD
1935 5665 deep vee, GA, longitudinal plate facing left. Larry N6LM 2/07.
1935 5669 deep vee, GA, longitudinal nameplate facing left. Warren K2UVV 8/06
1935 5731 shallow vee, GA
1935 5751 Shallow Vee, GA
1935 5754 Shallow vee (at http://www.americanradiomuseum.org/site/ ; info from N7CFO)
1935 xxxx shallow vee, GA; plate missing
1935 5771 deep vee, GA
1935 5779 deep vee, GA
1935 5793 deep vee, GA (Lynn, N7CFO)
1935 5798 Deep Vee, GA
1936A 5084 two paddles, split con bar
1936A 5089 two paddles, split con bar
1936A 5636 two paddles, split conn bar
1936A 5110 knob/paddle
1936A 5114 two paddles. Lou Borkowski K2EAI 5/07
1936A 5117 two paddles, term holes in base, missing weights and feet
1936A 5118
1936A 5162 two paddles
1936A 5167
1936A 5173 two paddles
1936A 5235 two paddles.
1936A 5269 pin jacks and extra holes added to base; paddles not original
1936A 5271 two paddles, complete, two plated steel weights. Bill, W4HEX, 10/08
1936A 5278 knob and paddle (paddle may not be original); one weight. (ebay Dec 2006)
1936A 5281 missing knob(?)
1936A 5283 2 paddles, with Bayside St. box .. Ray WB6L
1936A 5296 2 paddles (ebay 11/05 )
1936A 5321
1936A 5371 2 paddles
1936A 5390 cast left hand base; missing knob(?)
1936A 5400
1936A 5801
1936A 5812
1936A 5825 (1936A based on written descr)
1936A 5894
1936A 5896
1936A 5917
1936A 5925 complete, nice condition Fred KT5X
1936A 5931
1936A 5958 missing knob
1936A 5978
1936A 5979 brass plate
1936A 5995 two paddles (home made?), one weight. Paul Mendes, P'town 9/08
small aluminum plate
1936 7356 (pivot type A or B?)
1936A 6548
1936A 6518
1936A 6569 Looks blue (completely painted) including nameplate (assumed to be aluminum) (ebay feb 2009)
1936A 6597 HB terminals added, base letters damaged
1936A 6603 Complete; repro pendulum clip by VK2IXV. (Herman Willemsen VK2IXV, ex-John K4NP)
1936A 6624 two paddles
1936A 6649
1936A 6665 Complete, near mint. JEff KE0MT (11/07)
1936A 6673 One weight, two non-original paddles. On ebay 2/08
1936A 6831 (W1IMQ May 2006)
1936A 6856 has two added holes that go thru the "E" in "KEY" underneath (Ebay 10/05)
1936A 6867
1936A 6935 no weights. Jeff KE0MT 11/07
1936A 6984
1936A 6994
1936A 7026
1936A 7028 Given to Don Hawley W4ZU by Ted McElroy, September 1937 (W1IMQ collection)
1936A 7037
1936A 7049
1936A 7051 pendulum removed (conv. to paddle?)
1936A 7052
1936A 7098
1936A 7124 One weight. Otherwise appears complete, and nice. on ebay Feb 2008
1936A 7129 terminals added at back left corner. (ex- SK w9nfk - w5few
1936A 7254 the usual terminals on base
1936A 7305 extension pendulum.
1936A 7310
1936A 7340
1936A 7345 rebuilt
1936A 7355 one weight; with unmarked cord and wedge. On ebay March 2007
1936A 7370
1936A? 7375
1936A 7385
1936A 7412 entire key overpainted aluminum color
1936A 7420 Missing knob, weights; plate worn. Dirk KB1HKN
1936A 7460
1936A 7553 knob (?)
1936A 7650 (aluminum plate assumed) Bill K0CDJ
1936A 7665
1936A 7777
1936A 7862
1936A 7819 John, G0RDO
1936A 7878
1936A 7916
1936A 7926 Good condition. One weight. (ex-WA2BCR, 11/08 Fabio IK0IXI K3QS)
1936A 7930
1936A 7938
1936A 8127 Complete, original. Dave WA3LKN
1936A 8163 HB terminals at left rear
1936A 8200
1936A 8257 original, complete, excellent. ex-Tom Stack WQ5J ... 5/2007 now Gary Harmon K5JWK
1936A 8281
1936A 8357
1936A 8444 HB terms on left side
1936A 8441 homebrew damper arm
1936A 8477
1936A 8482
1936A 8508
1936A 8514
1936A 8520 ckt closer and terminals added
1936A 8524
1936A 8532 2 weights, missing knob
1936A 8544
1936A 8574 homebrew damper
1936A xxxd Eves Radio decal (no plate), Eves was in England (Tom W1IMQ)
1936B 5931 late, with base terminals
1936B 5987 terminals on base
1936B 6534
1936B 6637 terminals on base
1936B 6652
1936B 6974 terminals on base
1936B 6976 terminals on base. Broken damper casting (factory? work-around added). Dave WA3LKN Oct 2007
1936B 7008
1936B 7075
1936B 7091
1936B 7093 no weights
1936B 7225 thru pins for plate
1936B 7235 base terminals
1936B 7268 base terminals, one weight, nice condition (ebay 6/08)
1936B 7510 base terminals; one weight, missing knob (ebay 5/06)
1936B 7655 Dave WA3LKN
1936B 7681 base terminals
1936B 7697 terminals on base
1936B 7768 zinc finished parts
1936B 7991
1936B 8115
1936B 8327 terminals on base; restored base finish and parts. (Tom W8FIB obtained 6/06 ebay)
1936B xxxa terminals on base; no plate, never had one
1936B xxxb terminals on base; no plate
1936B xxxc no terminals on base; brass finished parts
1936B xxxe base terminals
Navy plate
The nomenclature on the plate is CMK-26009; these keys have "property of U.S. Navy" cast on the left side.
NAVY 60 ckt closer, stay cord eye between terminals (Lynn N7CFO)
NAVY 75 ckt closer, stay cord eye between terminals (Tom W1IMQ)
NAVY xx plate missing (Tony Rogozinski)
small aluminum plate (Quotes give left side casting.)
There are a few variations on this commercial version of the Navy bug. Most common is the "property of" keys that have "US Navy" ground off; a few of these are cast blank afer "property of" (if unstated below, I have no information). Some have "mfd in Boston Mass USA" cast on the side, while the rarest has the left side entirely cast blank. At least one of these keys has a circuit closer (if unstated, I have no information).
1937 6718 "property of" ("US Navy" ground off)
1937 6789 "mfd in boston mass usa"
1937 6842 "property of" ("US Navy" ground off)
1937 6964 "mfd in boston mass usa"
1937 7207 "mfd in boston mass usa"
1937 7212 "mfd in boston mass usa" no ckt closer (W1IMQ)
1937 7215 "mfd in boston mass usa" ... John SM5EDX Sweden ... March 2007
1937 7489 "property of" ("US Navy" ground off)
1937 7493 "property of" ("US Navy" ground off)
1937 7561 no legend (cast blank)
1937 7577 "mfd in boston mass usa"
1937 7633 "property of" ("US Navy" ground off)
1937 7721 "property of" ("US Navy" ground off). John G0RDO
1937 7726 "property of" ("US Navy" ground off)
1937 7755 "property of" remainder cast blank?
1937 7790 "property of" (Lynn Cannady 5/06)
1937 7996 "property of" (Alex, XE1CK, he put it on ebay 2/07, 1/09)
1937 7884 "property of" ("US Navy" ground off)
1937 8142 "mfd in boston mass usa". No ckt closer. Repainted. (Dave WA3LKN, from ebay 10/08)
1937 8262 "property of" ("US Navy" ground off); has ckt closer
1937 8270 "property of" ("US Navy" ground off, "James R. Holt" printed in the space.) Has ckt closer. Hole drilled in base nicks nameplate. (W1IMQ)
1937 8363 "property of" (then stamped by owner "L.O. BOYTS")
1937 8397 "property of" remainder cast blank; no ckt closer (W1IMQ)
1937 8402 "property of" ("US Navy" ground off) ebay 5/07
large plate models
Notations on the bugs below re dot stabilizers or circuit closers is for informational purposes. No conclusion should be drawn from the lack of a notation.
variation unknown:
1938 604 deluxe; dot stab; check pivot type
1938 1500 deluxe, thin dot stab
1938 1712 deluxe, shorting switch
1938A 225 deluxe, black, dot stabilizer
1938A 229 deluxe, black, large dot stabilizer
1938A 342 deluxe, Marbleite, dash bar gone, large dot stab.
1938A 347 deluxe, poor Marbleite, large dot stabilizer (K2UFT)
1938A 392 deluxe, ckt closer, black crackle
1938A 1730 deluxe, ckt closer, thin dot stab. "W4PCO" scratched on bottom. (Tom French W1IMQ)
1938A 5220 Standard
1938B ---- Deluxe, ckt closer, thin stab; no number on plate (more than one known; including one without a stablizer)
1938B 420 Deluxe; large dot stab.; no ckt closer
1938B 426 Deluxe, no ckt closer. Has large dot stab
1938B 485 Deluxe, with ckt closer and large dot stabilizer
1938B 497 deluxe
1938B 503 deluxe
1938B 508 Deluxe, large dot stab.
1938B 509 Deluxe. Found in the crawl space of a house in Edgerton MO. Looks like large dot stab. No knob, paddle, weights.
1938B 517 deluxe, with ckt closer. No dot stab
1938B 540 deluxe, ckt closer, large dot stab
1938B 550 deluxe, ckt closer, large dot stab (2008: Fabio, IK0IXI)
1938B 651 deluxe, ckt closer, dot stab type unknown, missing weights and knob (ebay Dec 2006)
1938B 672 deluxe, ckt closer, large dot stab. Homebrew paddles. Brass weight & term nuts. Nice Marbleite. (W1IMQ 4/09)
1938B 689 deluxe, ckt closer, large dot stab
1938B 703 deluxe, ckt closer, large dot stab (F. Skinner KA4JQZ 6/06)
1938B 731 deluxe, ckt closer, large dot stab
1938B 769 deluxe, large dot stabilizer, NO circuit closer. (John, G0RDO)
1938B 788 deluxe, ckt closer; thin (?) dot stab
1938B 802 deluxe, large dot stab
1938B 811 Deluxe, large dot stab.
1938B 819 Deluxe, thin dot stabilizer
1938B 823 Deluxe, thin dot stabilizer. No weights (ebay3/09 ex Don Iverson)
1938B 830 Deluxe; large dot stab. No shorting switch (ebay 10/07)
1938B 839 Deluxe; large dot stabilizer; complete, nice (ebay March 2007)
1938B 852 Deluxe, ckt closer, large dot stabilizer
1938B 853 Deluxe, large dot stab; missing ckt closer
1938B 858 Deluxe, thin dot stabilizer, ckt closer, both weights. Not much marbleite finish, non-original paddles. (Richard Sharisky 4/08)
1938B 882 Deluxe, ckt closer, large dot stabilizer (ebay 9/2006)
1938B 919 Deluxe, large(?) stab., missing knob, paddle, one weight, fair finish (Denton, W3KS, Dec 2008)
1938B 933 Deluxe; base finish needs restoration. (Tom WA0POD 5/07)
1938B 968 Deluxe, ckt closer, large dot stab., Plate on upside down (Randy, AA2U May 2007)
1938B 969 Deluxe, ckt closer, large dot stab. (Tom French W1IMQ)
1938B 1024 Deluxe, large dot stab., ckt closer (Barney W1QA, to Joe W1RRN about 1978, to Neil K6SMF 2008)
1938B 1036 Deluxe. No wgts, damaged damper
1938B 1037 Deluxe. Thin dot stab, ckt closer. No weights. (Rick, KE7UXE, Aug 2008)
1938B 1045 Deluxe. Large dot stabilizer
1938B 1046 Deluxe; ckt closer, large Stab, RCMP owner's tag
1938B 1098 Deluxe; thin stab; ckt closer
1938B 1100 deluxe; ckt closer
1938B 1120 deluxe; ckt closer, thin stab ?
1938B 1123 deluxe; ckt closer, thin stabilizer
1938B 1129 deluxe, ckt closer, large dot stab
1938B 1158 deluxe, ckt closer, dot stab.
1938B 1199 deluxe; ckt closer, dot stab.
1938B 1219 deluxe; ckt closer, thin stab.
1938B 1253 deluxe; ckt closer, thin stab.; 3 holes in T-bar (factory?)
1938B 1264 deluxe; ckt closer; no dot stabilizer; poor finish; missing knob. (ebay 4/09)
1938B 1269 deluxe; ckt closer; no dot stab; chips on tee-bar; two Speed-X or Vibro paddles (5/09 Alex T77Z)
1938B 1282 deluxe; ckt closer, thin dot stabilizer. Complete, nice. Ron McMullen from ebay Aug 2006
1938B 1297 deluxe; closer; thin stab; hole in nameplate
1938B 1305 deluxe; thin stabilizer
1938B 1308 deluxe; thin stabilizer
1938B 1313 deluxe, thin stabilizer
1938B 1371 deluxe; ckt closer, thin stabilizer (lynn n7cfo put it on ebay 1/2008)
1938B 1398 deluxe, ckt closer, thin dot stab. (missing finger?). Replaced paddle, one weight. (ebay 8/06)
1938B 1425 deluxe; thin stabilizer; broken paddle
1938B 1446 deluxe; with stabilizer
1938B 1458 no stabilizer
1938B 1463 deluxe; thin stabilizer. two paddles, two weights (one screw incorrect). Nice plate and finish. (David Ballantine KK4DW)
1938B 1517 deluxe; ckt closer, thin stabilizer
1938B 1525 deluxe; ckt closer, no dot stabilizer. Nice condition (Ebay 1/07)
1938B 1546 Deluxe, thin dot stab
1938B 1595 Deluxe; thin stab (? hard to see in photo)
1938B 1569 Left handed Deluxe factory mod. No stab or closer
1938B 1611 Deluxe (refinished black crinkle) no closer, no stab.
1938B 1613 Deluxe
1938B 1633 Deluxe (on QTH.com for sale by NR1R) B version not verified
1938B 1638 Deluxe, ckt closer, thin dot stabilizer
1938B 1658 Deluxe, ckt closer, thin dot stabilizer
1938B 1666 Deluxe, ckt closer, thin dot stabilizer (ebay June 2007)
1938B 1721 Deluxe, thin stab, dupe SN at top of plate
1938B 1731 Deluxe, ckt closer, thin dot stabilizer
1938B 1738 Deluxe, thin stab, 175 Congress on box
1938B 1764 Deluxe, ckt closer, (dot stab?), poor condition
1938B 1772 Deluxe; no circuit closer; thin dot stab
1938B 1776 Deluxe, ckt closer, dot stab
1938B 1794 Deluxe, ckt closer, thin dot stabilizer. With box (ebay 8/06)
1938B 1808 Deluxe, ckt closer, thin dot stabilizer, with box, mint! Tom K4NCG
1938B 1823 Deluxe, ckt closer, thin stab, 175 congress
1938B 1886 Deluxe, thin dot stab
1938B 1903 Deluxe, ckt closer, thin dot stab, Customized w/red fittings! (ebay 5/07 & 9/07 from France)
1938B 1908 Deluxe, thin dot stab, wrong paddle & knob
1938B 1934 Deluxe, thin dot stab
1938B 1935 Deluxe, thin dot stab, ckt closer, clear (replaced) paddles
1938B 1941 Deluxe, thin dot stab, ckt closer. ex-Murray Willer collection
1938B 1979 Deluxe, thin dot stab, ckt closer. One weight, Vibroplex knob and paddle. (eBay 1/08)
1938B 1996 deluxe
1938B 2006 deluxe, shorting sw., thin stabilizer, VE5WO label
1938B 2016 Deluxe; no dot stab
1938B 2027 deluxe; ckt closer; thin dot stab. (Tom French W1IMQ)
1938B 2045 deluxe, ckt closer, thin dot stabilizer
1938B 2068 Deluxe; ckt closer; dot stab.
1938B 2124 Deluxe; ckt closer; no dot stab
1938B 2172 Deluxe
1938B 2200 Deluxe; ckt closer, thin dot stabilizer John Snell G0RDO
1938B 2210 Deluxe; ckt closer; thin stab; one wght; no knob
1938B 3234 Deluxe; ckt closer, thin dot stab. Very nice Marbleite. Jeff Garrett KE0MT 11/07
1938B 3250 Deluxe, ckt closer, thin stab
1938B 3251 Deluxe
1938B 3431 left-handed Deluxe (factory modified right-hand casting); ckt closer, no dot stab. (Tom French W1IMQ)
NOTE, the 1938 standard did not come with a dot stabilizer or a circuit closing switch.
1938B 5033 Standard
1938B 5077 Standard pivot shaft is a drill bit! John KO4XJ, June 2008
1938B 5133 Standard
1938B 5151 standard
1938B 5205 standard Rough condition. Rich WB9LPU July 2006
1938B 5236 Standard
1938B 5261 Standard
1938B 5274 Standard. One weight. (Knob and paddle reversed) Walt Jones K0EYN ex-ebay 1/08
1938B 5282 standard
1938B 5306 standard
1938B 5320 standard Bobbi KB9GKX
1938B 5330 standard Nice condition, but missing both weights. On ebay 5/08
1938B 5355 standard
1938B 5376 standard
1938B 5377 standard missing weights, paddle and knob; wrong dot spring screw
1938B 5439 standard, complete, surface rust
1938B 5460 standard
1938B 5517 refinished gray hammertone by John C. McElroy (Ted's son)
1938B 5535 standard,
1938B 5541 standard, four weights
1938B 5545 standard
1938B 5548 standard, one weight
1938B 5606 standard, Fahnestock clips on terminals, knob replaced by a second paddle (ebay Feb 2009)
1938B 5614 standard,
1938B 5615 standard, one weight, no dot stab. Stamped W.R. Crooks on damper (ebay 9/08, Fabio IK0IXI)
1938B 5647 standard,
1938B 5676 Standard; chromed parts, 1/4" deluxe contact screws (3/16" contacts). John G0RDO
1938B 5705 Standard; large weight and small weight
1938B 5716 Standard.
1938B 5735 standard.
1938B 5752 Standard. John K4NP (8/06) Paddle replaced.
1938B 5795 Standard; no dot stab. ... Ebay 11/06, appears complete and nice.
1938B 5803 Standard
1938B 5832 Standard Mike VE3FGU
1938B 5850 Standard, no damper or ground terminal, 1 weight, broken paddle (ebay 3/09 ex-Don Iverson)
1938B 5862 Standard; wrong paddle
1938B 5876 Standard; nice condition
1938B 5878 standard; In England
1938B 5907 standard; modified into a paddle; in England 10/05
1938B 5935 standard;
1938B 5939 standard; (ebay June 2007)
1938B 5941 standard,
1938B 5946 Standard; nickeled parts
1938B 6018 standard
1938B 6045 Standard
1938B 6052 Standard; homebrew ckt closer
1938B 6172 Standard
1938B 6174 Standsrd, no dot stabilizer. Dave WA3LKN, oct 2007
1938B 6190 Standard
1938B 6195 Standard
1938B 6226 Standard
1938B 6230 Standard, no dot stab, no ckt closer (ebay 10/08)
1938B 6274 Standard; nameplate appears stripped, is affixed to base with screws (eBay 10/06)
1938B 6335 standard
1938B 6369 standard
Note, a circuit closer was normal on the 1939 Deluxe models, but they typically did not have a
dot stabilizer. Notations on the Deluxe or Standard 1939s below re "no dot stab" or "no ckt closer"
is for informational purposes. No conclusion should be drawn from the lack of a notation.
1939 xxxx Deluxe; no nameplate, bought at Ft. Monmouth
1939 3235 Deluxe, no (never had) ckt closer
1939 3239 Deluxe. Thin dot stabilizer. Complete, near mint. (Max M0GHQ; Sept 2007)
1939 3270 Deluxe. Complete, perfect finish and nameplate. (W1IMQ collection)
1939 3300 Deluxe. Complete. Has thin dot stabilizer.
1939 3301 Deluxe. Complete, white knobs and paddle. Thin dot stabilizer. (ebay 6/08)
1939 3348 Deluxe; missing pendulum, knob, terminal nuts. Nice base... (ebay 12/7)
1939 3349 Deluxe. One weight, otherwise complete and near mint (W1IMQ collection)
1939 3388 Deluxe
1939 3487 Deluxe. Presented to Bill Burgess W1BDS by Ted McElroy, Spring 1939. (W1IMQ collection)
1939 3538 Deluxe. Complete, nice. No dot stab.
1939 3543 Deluxe
1939 3550 Deluxe
1939 3566 Deluxe
1939 3570 Deluxe Complete. (ebay June 2006)
1939 3602 Deluxe.
1939 3616 Deluxe. Complete. (ebay 2/07)
1939 3619 Deluxe
1939 3642 Deluxe, missing knob, no ckt closer
1939 3645 Deluxe. One weight & screws by W2GFF. Vibroplex paddle. Marbleite finish gone. Terry K4RX 11/07
1939 3657
1939 3661 deluxe (ex-Murray Willer; ex-KK4DW)
1939 3663 deluxe; missing knob
1939 3666 deluxe
1939 3676 deluxe
1939 3708 deluxe
The Standard models did not have a circuit closer or dot stabilizer. Notes to that effect are only for confirmation.
1939 ---- standard; no serial number on plate (NR5Q)
1939 6317 standard
1939 6405 standard
1939 6421 standard; on ebay 2/07 by the Pavek Museum. Nice, complete, chipped paddle at forward screw.
1939 6460 standard
1939 6494 Standard. complete; broken paddle, some rust. KN1K 9/07
1939 6502 Standard, no dot stab or ckt closer. Replacement paddle, otherwise complete. (ebay 5/09)
1939 6523 Standard; has dot stab
1939 6538 Standard; no dot stab, no ckt closer (ex-Tom Perera W1TP, now Boris Svagelj S57LO)
1939 6577 Standard. no dot stab. 1 weight, wrong paddle (ebay 3/09 ex-Don Iverson)
1939 6618 Standard
1939 6673 Standard; w/box & modern? cord
1939 6676 Standard; w/ box and adv paper
1939 6679 Standard
1939 6727 Standard, very good condition. Pete W5PEH (ex-Richard Maxwell Jr K3BL SK his widow put it on ebay 6/08)
1939 6743 Standard
1939 6756 Standard
1939 6758 Standard, Mint w/ box (Randy AG4NA)
1939 6775 Standard
1939 6799 standard
1939 6851 standard, one weight, chipped paddle (Ron W9EOA)
1939 6863 standard
1939 6881 Standard
1939 6890 Standard
NOTES: (See the Mac-Key page for identification photos)
--A. 1935 models: The "shallow vee" is the earlier model with the fixed contact connector bars meeting high on the frame, forming a shallow (large) included angle. On the late 1935 "deep vee" variation the bars meet low on the frame forming a deep or smaller included angle.
--B. GAD, GA: During the 1935 model run the lower lever pivot hole in the base, previously a blind hole accessed from above, was extended fully thorough the base, obliterating the final letter in the abbreviation of "guaranteed" in the cast lettering under the base. Originally reading GAD, it then read GA followed by the hole.
--C. The 1934, 1935 and early 1936 bugs had two paddles. Later bugs had the usual thumb paddle and finger knob.
--D. 1936A split conector bar: The U-bar holding the fixed contacts was in two pieces (each "L" shaped) on the very early 1936 models.
--E. 1936A, B: Early bugs through the 1936A had a cast brass lever pivot assembly. During the 1936 model run, the main (or dot) and dash levers were cut from steel bar stock, creating the 1936B and later models. It still retained separate pivot points for the main (dot) and dash levers. (See 1938B, below.)
--F. The "x" (as in 1936x) indicates that I am lacking information to fully classify the key.
--G. The "1937" models are civilian models of the Navy bug. There are three (possibly four) known variations, which are identified by the legend on the left side.
--H. 1938A, B: Part way through the 1938 models McElroy changed the steel-bar pivot from having separate pivot points for the main (dot) and dash levers, to the Vibroplex "bent-lug" design having a common pivot for both levers, resulting in the 1938B and following models.
--(H, cont'd) 1938B Standard: Notations that it has no dot stabilizer or circuit closer does not mean that it should, it merely serves to verify that this model was not so supplied.
--J. The "dot stabilizer" (dot spring pre-tensioner) used on the 1938 Deluxe models came in two styles. The early large style has the tensioning finger set in a block on the pendulum and the dot contact attached to the block. The later thin style holds the tensioning finger only, the dot contact is separately attached to the pendulum.