Grinding Your Own FT-243 — The 2026 Edition | VK6ADA

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Grinding Your Own FT-243

The 2026 Edition — sourcing, tools, technique, and the vintage library behind the craft

From the 1940s through the 1970s, the FT-243 crystal unit put rock-bound frequency control in everything from the BC-611 handie-talkie to a generation of Novice transmitters. Hams of that era thought nothing of opening a surplus holder and lapping the quartz blank to a greener spot in the band. With International Crystal Manufacturing closing its doors in 2017 after 66 years[11], the era of ordering a cheap custom-cut rock is over — but every skill, document, and material needed to finish your own crystals is still available in 2026. This guide collects all of it in one place.

Scope. This article covers hand-lapping pre-cut quartz blanks to a target frequency — the same craft described in QST in 1946[5]. It does not cover cutting blanks from raw quartz, which requires a diamond saw and X-ray goniometer orientation; angular errors of a fraction of a degree ruin the temperature coefficient, which is why even wartime plants moved to instrument-oriented cutting[6].

I. A Two-Minute History

When the United States entered World War II, the handful of firms that knew how to make quartz crystal units faced a production demand measured in the tens of millions. The know-how available to new manufacturers amounted to a few QST articles, a couple of Bell System Technical Journal papers, and the issued patents. Bell Telephone Laboratories responded by releasing a collection of internal papers by W. P. Mason, Walter L. Bond, Roger Sykes, I. E. Fair, G. W. Willard and colleagues; these were later edited by R. A. Heising into the 1946 Van Nostrand volume Quartz Crystals for Electrical Circuits, which remains the definitive record of natural-quartz-era manufacturing[1][6].

The wartime program also solved the crystal aging problem — the Signal Corps concluded that its radio circuits could only be satisfied by quartz plates etched to final frequency, a requirement formalized at the 1944 crystal conferences[7]. Western Electric’s Hawthorne plant alone produced more than ten million FT-241 units between 1941 and 1945[6]. After the war, Bell Laboratories developed commercial hydrothermal growth of synthetic quartz by 1950, and by the 1970s essentially all electronic-grade quartz was cultured rather than mined[12]. If you want the natural-quartz process detail — faced Brazilian quartz, oil-immersion inspection, wire saws — the 1940s documents below are where it lives.

II. The Vintage Library (1939–1981)

Every document below is a free, legal download or full-view scan. Together they cover the complete production chain: raw quartz inspection, orientation, sawing, lapping, etching, mounting, holders, ovens, and oscillator design.

DocumentYearWhere to Get It
Heising (ed.), Quartz Crystals for Electrical Circuits: Their Design and Manufacture, D. Van Nostrand[1] 1946 (EIA reprint 1982) Full-view scan at HathiTrust. The Bell Labs anthology; Chapter XVI documents FT-241 production at Hawthorne end to end. EIA-reprint hard copies are inexpensive used.
Buchanan, Handbook of Piezoelectric Crystals for Radio Equipment Designers, WADC Technical Report 56-156 (AD 110448)[2] 1956 701-page PDF at worldradiohistory.com; mirror at tubebooks.org; catalog entry at DTIC. Crystal elements, holders, ovens, military unit groups, and oscillator design.
Bliley Electric, Engineering Bulletin E-6, Frequency Control with Quartz Crystals[3] 1940 PDF at worldradiohistory.com. Period manufacturer literature: X-, A- and B-cut plates from 16 kc to 11,000 kc, bar crystals, and activity testing.
Bliley, Quartz Crystals / Crystal Oscillators booklet[4] 1940s Scan at the Internet Archive.
Cowles (W1AOK), “Crystal Grinding,” QST[5] April 1946 Reproduced at bliley.net. The classic hands-on lapping article, written by a ham working at Crystal Research Laboratories.
RCA V-cut crystal pages, 1939 catalog[8] 1939 Reproduced at novioljourneys.com, with RCA’s description of its V-cut manufacturing steps for broadcast crystals.
Bottom, “A History of the Quartz Crystal Industry in the USA” (35th Frequency Control Symposium)[6] 1981 Republished by IEEE UFFC. The best single narrative of wartime production methods, X-ray orientation, and the FT-241/FT-243 programs.
Burch, “The 1944 Crystal Conferences”[7] — At IEEE UFFC. The aging problem and the etch-to-frequency mandate, plus a bibliography of the era.
Proceedings of the Annual Frequency Control Symposium (Fort Monmouth, 1947–)[9] 1947–1980+ Search DTIC. The primary record of postwar crystal manufacturing R&D: synthetic quartz growth, contour grinding, cold-weld enclosures, chemical polishing.

III. Sourcing: Blanks, Hardware, and Consumables

Crystal blanks — the sensible starting point

SupplierWhat They Offer
QRPme (Rex Harper, W1REX) The most active supplier in the hobby. Custom-cut rectangular FT-243 blanks at 7015 kHz sold in three-packs — positioned so they can be lapped to nearly any 40 m frequency — plus a grinding-supplies accessory pack, FT-243 sockets, and the X-CHECKer oscillator/frequency-counter kit for measuring as you grind[10].
AF4K Crystals Bulk boxes of 100–200 clean quartz blanks cut for FT-243 holders, mixed from roughly 1000–8500 kHz, at hamfest-bin prices — plus the full rebuild hardware: contact plates, phenolic insulators, and copper/tin/brass electrodes in hundred lots[13]. Order through the current store link; the old onlinehome.us pages are no longer active.
Hamfests & eBay Surplus out-of-band FT-243s are raw material. Units just below a band edge (6950–6975 kc for 40 m) are the prime candidates; cheap far-out-of-band units are ideal for practicing the lapping stroke[10]. Vintage 1950s “grind your own” kits with holders, blanks, and instructions still surface occasionally[14].
Custom-cut oriented blanks With ICM gone[11], the remaining houses that will quote small quantities of oriented AT- or X/Y-cut blanks include Laptech Precision (Ontario, Canada), KRYSTALY, Hradec Králové (Czech Republic), and Andy Fleischer, DC9XP (Bremen, Germany), long-time supplier of custom crystals for military and vintage sets[13]. Email for quotes on bare blanks.

Lapping tools and consumables

ItemSource & Notes
Plate-glass lap A square foot of ¼-inch plate glass with rounded edges from any local glass shop, plus a smaller glass “button” slightly larger than the blank to keep pressure even and the faces flat[5][14].
Silicon carbide grit (400 / 600 / 1000 mesh) Lapidary suppliers: Kingsley North, Rio Grande, or eBay. 3M wet/dry silicon carbide paper from any auto parts store works for coarse stock removal; the old-timers used everything from household abrasive cleanser to toothpaste for the fine work[14].
Micrometer (0–1″) Any machinist supplier. Constant parallelism checks are the entire game — the faces must be flat, smooth, and dead parallel[14].
Test oscillator + frequency counter QRPme’s X-CHECKer kit purpose-builds this (favorably reviewed in QST, November 2017)[10], or use any bench counter with a simple Pierce test oscillator per Bulletin E-6[3].
Cleaning supplies Warm water and soap with a soft toothbrush, a bowl of clean water and one of alcohol for rinsing, and gloves — skin oil on the blank or electrodes is the leading cause of a dead-acting crystal[5][14].

IV. The Technique in Brief

The method below is a modern summary of Cowles’ 1946 QST procedure[5] as practiced and taught today by Rex Harper, W1REX[10]. Read both sources in full before your first blank.

  1. Pick a realistic move. Grinding only raises frequency. Small moves are routine; large moves risk a dead blank. For 40 m, start from 6900 kc or above. 160–40 m blanks lap well; above roughly 10 MHz the quartz becomes too thin and tends to crack — the vintage answer was overtone operation, the modern one is chemical etching to final frequency[14].
  2. Open and clean. Disassemble the holder, note the stack order, and scrub the blank and electrodes with soap and warm water. Handle with gloves from here on.
  3. Lap with the button. Wet grit on the plate glass, blank under the glass button, and grind with a uniform figure-eight stroke, rotating the blank regularly. Uniformity is everything: humps or wedge in the quartz kill activity.
  4. Measure obsessively. Check thickness with the micrometer across all four corners and the center at short intervals, and check frequency in the test oscillator often as you approach target. Sneak up on the last kilohertz with fine grit only.
  5. Restore activity. If the crystal goes sluggish at frequency, clean it first — dirt and moisture are the usual culprits. If it is still down, bevel all eight edges; beveling restores activity and nudges frequency up slightly, so leave margin for it[5].
  6. Reassemble clean and dry. Wipe the holder interior with alcohol, verify the electrodes are spotless, reassemble, and confirm activity and frequency in the target rig’s oscillator, not just the test set.
Expectations. Experienced hands report success rates around four or five good crystals out of six once the stroke is learned, and moves of a couple hundred kilohertz are achievable with discipline — but every one of them cracked blanks learning it[14]. Buy the bulk blank box, not one precious rock.

V. On Raw Quartz

Cultured quartz bars are cheap from lapidary rough dealers and eBay, and it is tempting to imagine sawing your own blanks. Resist it, at least at first. Producing a usable AT-cut blank requires orienting the saw cut to the crystallographic axes within a small fraction of a degree, which is why the wartime industry’s first collective act was to expedite X-ray diffraction orientation equipment[6]. Buying pre-oriented blanks and doing the finishing yourself delivers 95% of the craft with none of the goniometer.

Credits

This guide stands on the work of the following people and institutions, with gratitude:

  • Francis R. Cowles, W1AOK — whose April 1946 QST article remains the foundational hands-on text for amateur crystal lapping.
  • Rex Harper, W1REX (QRPme) — for keeping the craft alive in the 21st century: commissioning new FT-243 blanks, designing the X-CHECKer, and teaching the grinding workshops (with Darell Brehm, WA3OPY, and Ron Hale, AC5UR) that started at OzarkCon 2006.
  • AF4K Crystals — for two decades of supplying FT-243 crystals, blanks, and rebuild hardware to the boatanchor community.
  • Raymond A. Heising and the Bell Telephone Laboratories authors (W. P. Mason, W. L. Bond, R. A. Sykes, I. E. Fair, G. W. Willard, et al.) — for the 1946 anthology that trained an industry.
  • John P. Buchanan / Philco TechRep Division — for the 1956 WADC handbook.
  • Virgil E. Bottom — for the definitive industry history.
  • The IEEE Ultrasonics, Ferroelectrics & Frequency Control Society — for preserving and freely publishing the historical record.
  • worldradiohistory.com, tubebooks.org, the Internet Archive, HathiTrust, and bliley.net — for scanning and hosting the primary documents.

Footnotes & References

  1. Raymond A. Heising (ed.), Quartz Crystals for Electrical Circuits: Their Design and Manufacture (New York: D. Van Nostrand, 1946); reprinted by the Electronic Industries Association, Washington, D.C., 1982. Full-view scan: HathiTrust Record 001481652. ↩
  2. John P. Buchanan, Handbook of Piezoelectric Crystals for Radio Equipment Designers, WADC Technical Report 56-156, Wright Air Development Center, October 1956, AD 110448. PDF: worldradiohistory.com; mirror: tubebooks.org; citation: DTIC AD0110448. ↩
  3. Bliley Electric Co., Frequency Control with Quartz Crystals, Engineering Bulletin E-6 (Erie, PA, 1940). PDF: worldradiohistory.com. ↩
  4. Bliley Electric Co., Quartz Crystals / Crystal Oscillators booklet. Scan: Internet Archive, quartzcrystalscr00unse. ↩
  5. Francis R. Cowles, W1AOK, “Crystal Grinding,” QST, April 1946, pp. 48–50. Reproduced at bliley.net. ↩
  6. Virgil E. Bottom, “A History of the Quartz Crystal Industry in the USA,” Proceedings of the 35th Annual Frequency Control Symposium, USAERADCOM, Ft. Monmouth, NJ, 1981. Republished at IEEE UFFC. ↩
  7. Ken Burch, “The 1944 Crystal Conferences,” IEEE UFFC history pages. ↩
  8. “Random thoughts on something not random… the quartz crystal,” novioljourneys.com, January 2017 — including reproduced pages from the 1939 RCA catalog describing V-cut crystal manufacture. ↩
  9. Proceedings of the Annual Frequency Control Symposium, U.S. Army, Fort Monmouth, NJ, 1947 onward. Public-domain volumes searchable at DTIC (apps.dtic.mil). ↩
  10. Rex Harper, W1REX, “X-CHECKer Crystal Grinding OSC/FC kit,” qrpme.com — kit documentation, blank availability, grinding video, and workshop history. ↩
  11. “Quartz crystal” tag archive, Hackaday — reporting International Crystal Manufacturing’s 2017 announcement that it was ceasing operations after 66 years. ↩
  12. “4 Hidden Mysteries of Quartz Crystal Oscillators,” Bliley Technologies blog — WWII demand, Bell Labs’ commercial hydrothermal process by 1950, and the transition to all-synthetic quartz by the 1970s. ↩
  13. AF4K Crystals store: current storefront. Custom crystals: Andy Fleischer, DC9XP, Bremen, Germany. Blank-cutting houses: Laptech Precision; KRYSTALY, Hradec Králové. ↩
  14. Community practice threads: “FT-243 Crystal Grinding?” and “Quartz Crystals,” Antique Radio Forums (t=136838) and (t=327796) — parallelism, beveling, abrasive choices, success rates, thin-blank limits, and glass-lap sourcing, contributed by N7AH, W7POW, WB6NVH, and others. ↩
Mike Peace VK6ADA / r-390a.net Administrator
vk6ada.com.au · Compiled July 2026 · 73