Meters covered - all require either fabrication of a ring mount for the supplied thermocouple or purchase of a commercial sensor. Approx prices updated 07/14/2010. More detail contained within the thread.
Low Cost: $15.99 with shipping -- Degrees C only, includes thermocouple.
$14.99 + 9.99 ship - Dual sensor, Degrees F/C selectable
DMM With Thermocouple input
Around $25-40
DMM Thermocouple adapter. Plugs into DMM, converts thermocouple output to read as a DC voltage, proportional to temperature. Example: 320mv = 320F.
Around $30-$100
Data Logging Dual Fluke 54 Thermometer - Around $350. Can capture samples are regular intervals, then transfer data to PC for graphing.
07/14/2010 update - added summary to top, and link to a low cost commercial ready to go CHT thread.
09/04/2009 updated - added specs for the meters. Be careful with the max temp rating, optional probes may be required, the probe insulation can't take that high heat. Where available, the factory supplied probe rating will be included. For CHT use, the factory supplied sensor is fine.
1st up - rock bottom CHT Total Cost - $11.88 w/shipping
eBay item: 180402989515
Thermocouple type: 'K'
Power: 9V 6F22 cell battery
Size: 11(L) 7 (W) 2.3(H)cm
Weight: 155g
Temperature Range: -50 degrees to 750 degrees C (- 58 to 1382F) of the TP01 Temperature Probe
Accuracy: +/- 0.75%
Resolution: 1 C
3 1/2 digital LCD display with max reading of 1999
Downsides: Short cable, only reads in degrees C
To keep a low budget, the included probe was used to make a spark plug ring mount. JB weld is good for 450 degrees, 500 intermittent. Their website says it is non-electrically conductive. Scrap of copper close match to plug gasket thickness. Buying a 14mm bit out of scope. 3/8" drill, ream out to 1/2, file to fit.
![Image](http://img515.imageshack.us/img515/6743/chthomemaderingsensor.jpg)
Finished ring lug and meter. Inset shows thermocouple tied to riing via 'Nomex' thread (non-flammable, good for 200C+) prior to glue & heatshrink tubing
![Image](http://img35.imageshack.us/img35/6233/chthomemadefinished.jpg)
On scooter, dropped into drink holder - measuring 179C. Conversion: F = C * 9/5 + 32 . Quicker way to do it in you head is F = (2 * C) - 0.1* (2 * C) + 32. With minor approximation we've got (2 * 180) ==> 360 - 36 ==> 324 + 32 ==> 356 F.
![Image](http://img137.imageshack.us/img137/8163/chtonscooter.jpg)
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2nd up - 2 input thermometer, reads C, F - Total cost: around $26.99, w/shipping
eBay item: 260465248857
Thermocouple type: 'K'
* Temperature range: -50┬░C to 1300┬░C ( -58┬░F to 1999┬░F)
* Battery: 9V battery (installed)
* Dimensions: 149 x 71 x 41mm
* Weight: 200g ( including battery )
* Included 2 ''K''-thermocouples
* Resolution : 1┬░C or 1┬░F, 0.1┬░C or 0.1┬░F (one k-type), 1┬░C or 1┬░F (two k-type)
2 x K type temperature test probe(-50 to 250┬░C)
Downside: pretty inexpensive looking, short probes
Upside: Has degree F button. Includes 2 themocouples, better quality then the first meter, they are braided fiberglass. Can display both channels <edit:--> *one* at a time, making a low cost CHT + EGT possible.
Used the same probe as 1st test.
![Image](http://img196.imageshack.us/img196/9205/chthomemadedualmeter.jpg)
=== Accuracy ===
Will run some accuracy tests. Informal tests on both meters showed good accuracy at boiling water temp. Thermal compensation is present. It adjusts for errors caused by ambient temperature changes.