ReSTored
Site Supporter
I have 3/8 and 1/2 wrenches and have probably been remiss in not re-calibrating them. About to start my prep for the 2018 season and wondering how often people do this and methodology.
Torque Wrench and Periodic Re-calibration
- Thread starter ReSTored
- Start date
- Joined
- Feb 11, 2006
- Messages
- 8,043
- Location
- Jacksonville
- Bike
- GL1800 R1200RT NC700
- 2025 Miles
- 006570
A good quality torque wrench in DIY use will probably never need calibration if the wrench is not abused or dropped and properly stored after use. A common suggestion from tool manufacturers is after 2500 repetitions. I have a 3/8" drive wrench I got new from my aircraft mechanic father and while I use it as needed I'll never achieve 2500 uses. The 1/4" and 1/2" ones in the garage are cheap Harbor Freight tools that are not economic to have lab calibrated. If I wanted to I could DIY check for error by hanging a known weight from a string and multiply the lever arm by the weight to get the amount of force needed to "click" it.
Bought a Snap On dial type wrench 0 - 150 ft.lb. in 1971 when starting a short career in the auto tech business. It never saw a lot of use at work, but more at home over the years. When I bought my new '95 ST1100, I decided to have the calibration checked, since those cam holder bolts don't take much torque at all - 9 ft/lb - not something to guess at. I don't remember the cost, but it wasn't much, way back then, and the wrench was still spot on. Still using it today and haven't worried about it since.
As said, for the DIY, a good torque wrench would probably not need calibration unless it is dropped. You will want to remember to store it at the lowest setting and locked in place to retain as much spring memory retention as possible.
An inexpensive DIY calibration tool can be a digital turque adapter. These are for guys that don't own a torque wrench and want to use a ratchet and this adapter. If you buy one of these that are calibrated, you can set your torque wrench to a setting and see what the digital adapter reads when you go "click".
My Snap-On 1/2" was off 3 lbs at 80 lbs. My Craftsman was off 2 lbs at 80 lbs. My 3/8" inch/lb was off 2 at 120.
My neighbor popped over with his when he saw me measuring mine. His Harbor Freight was off 13 ft/lbs at 80...
This is like the one I picked up:
https://www.amazon.com/ACDelco-ARM6...&sr=1-1&keywords=Digital+Torque+Adapter+delco
An inexpensive DIY calibration tool can be a digital turque adapter. These are for guys that don't own a torque wrench and want to use a ratchet and this adapter. If you buy one of these that are calibrated, you can set your torque wrench to a setting and see what the digital adapter reads when you go "click".
My Snap-On 1/2" was off 3 lbs at 80 lbs. My Craftsman was off 2 lbs at 80 lbs. My 3/8" inch/lb was off 2 at 120.
My neighbor popped over with his when he saw me measuring mine. His Harbor Freight was off 13 ft/lbs at 80...
This is like the one I picked up:
https://www.amazon.com/ACDelco-ARM6...&sr=1-1&keywords=Digital+Torque+Adapter+delco
Beam-Type torque wrenches (the cheapest "sharpened stick attached to rod" versions) and the more expensive Split-Beam Type generally are the longest to hold calibration.
Example Cheap Beam: https://www.acklandsgrainger.com/en/product/TORQUE-WRENCH-BEAM-TYPE-1-2IN-DR/p/WSWTWB12150
Example more expensive Split Beam: https://www.amazon.ca/Precision-Instruments-PREC3FR250F-Silver-Torque/dp/B002XMSFIM
The first type is dead simple, and unless something happens to bend either element beyond elastic rebound, cannot go out of calibration. The issue is of course readability due to parallax and clumsy usage angles.
The second type, since its measuring components are not under load, generally just works. I've a unit from a professional source (it was sold to me refurbished) I used for five years. Took it back to them to have it calibrated (would have been affordable, as the company I was employed at was of "valued" status to the torque wrench supplier), and it was fine.
Example Cheap Beam: https://www.acklandsgrainger.com/en/product/TORQUE-WRENCH-BEAM-TYPE-1-2IN-DR/p/WSWTWB12150
Example more expensive Split Beam: https://www.amazon.ca/Precision-Instruments-PREC3FR250F-Silver-Torque/dp/B002XMSFIM
The first type is dead simple, and unless something happens to bend either element beyond elastic rebound, cannot go out of calibration. The issue is of course readability due to parallax and clumsy usage angles.
The second type, since its measuring components are not under load, generally just works. I've a unit from a professional source (it was sold to me refurbished) I used for five years. Took it back to them to have it calibrated (would have been affordable, as the company I was employed at was of "valued" status to the torque wrench supplier), and it was fine.
I usually get all mine calibrated at work yearly (for free). I wouldn't pay more than $20 each. If my current employer can't do it my dad's friend runs a metrology company and I can either throw him a little cash or some beer to have it done.
For what it's worth, the $20 harbor freight wrenches have always been super close to dead on out of the box. They hold calibration well. The overall construction is sub par but they don't break easily and stay calibrated - go buy another one if it falls out of calibration or it breaks. I have two, and for general use it's nice.
For what it's worth, the $20 harbor freight wrenches have always been super close to dead on out of the box. They hold calibration well. The overall construction is sub par but they don't break easily and stay calibrated - go buy another one if it falls out of calibration or it breaks. I have two, and for general use it's nice.
for the 9 ft/lb bolts you generally use a smaller torque wrench calibrated in inch/lbs, and set it to 108-ish. I seem to recall most torque wrenches are spec'd to a certain % accuracy in the top 80% of the range, the lowest 20% is not spec'd. Using a 0-150 ft/lb wrench for that application is a bit dicey, but the snap-on dial type are probably as good as it gets accuracy wise. Back in the '80s I had a friend who used them professionally in aircraft related applications and IIRC he claimed that while they were very accurate out of the box, they seemed to go out of calibration easier than other ones if you didn't handle them very carefully.
I do my own with a tape measure a weight scale and my force. Google it or you tube it. It's quite simple
STripper
Brian
It's generally a bad idea to use a 0-150 ft. lb. torque wrench on bolts that require only 9 ft. lbs. Use a smaller wrench and "get into the depth of the scale." I use my 1/4", 3/8" and 1/2" wrenches significantly less than a professional mechanic, and used to have them calibrated at work every few years for free. They never drifted once.
Served me well for over 20 years on the bike, measures in 1 lb increments.
Andrew Shadow
Site Supporter
I doubt that anything that is being torqued on a motorcycle is sensitive enough for this to have an effect but for what it is worth all of the training that I received on the proper use of torque wrenches always instructed that a click type torque wrench should never be used in the lower 20% or the upper 20% of its range. They are most accurate in the 20 to 80% range. This is to be factored in to the decision of which range of torque wrench is chosen for any given job. The instruction sheet that came with one of my Snap On torque wrenches also states to avoid the upper and lower 20% whenever possible. Of course at work this was not an issue as we had every conceivable range possible available so we had no reason not to respect this criteria. Not so easy at home.