Date:Mar. 10, 2018


Brief Description:No more turn it till it snaps and back off a quarter turn!

Ordered new dial type torque wrenches

My standard operating procedure is to tighten a threaded fastener until it snaps and back off a quarter turn.  While this works on the washing machine and the lawn mower, the RV-10 is not a place where this method is acceptable.  The only thing more dangerous than an UNDER-tightened threaded fastener is an OVER-tightened threaded fastener.  As it turns out the click style torque wrench that everyone has always used is NOT the only way to get the job done.  I have always disliked these as they must be turned back from the torque “setting” prior to storage, calibrated OFTEN, and hand placement is critical for the proper torque application.  After all of this they always leave me wondering if the job got done “right”.  Much to my delight there are other options.  The deflecting beam is my choice.  These require very little maintenance as there are no parts under torque unless they are being used.  There is a more sophisticated deflecting beam torque wrench that uses a dial indicator.  Beyond this dial that indicates the torque being applied some of them have a max torque pointer that will register the highest torque that has been applied since the last time the pointers knurled knob was spun to zero.  Now we are talking!  CDI and Precision Instruments  (PI) both make dial models.  PI makes a model that even has a light to turn on when the desired torque is reached in place of the maximum torque pointer although it is a bit pricey.  One common thing is that a torque wrench is not accurate to their published accuracy spec until 20% of the maximum rated torque of the wrench is applied.  So a wrench with a max torque of 100inch pounds means that it will not be accurate until 20inch pounds are applied.  If we apply this to the Vans Aircraft 5.20 Nut and Bolt Torques we will need (3) wrenches to supply torque in the proper amounts with accuracy.  Interesting to note they don’t have a torque wrench listed on their tools lists for RVs.  After comparing and contrasting the various options and price points I decided that CDI dial models were the way to go for the inch pound units.  I opted for the  CDI 752LDINSS (75inch pound max) and the CDI 3002LDINSS (300inch pound max) tools.  These two wrenches will accurately torque up to AN6 bolts/nuts.  For AN7-AN10 bolts/nuts another wrench will be needed with approximately a 200ft pound max rating.  The limitation on the dial type wrenches is that you must watch the dial (unless you have the light option) to see the torque as you are applying it.  If you have every used a 100ft pound setting on a click type wrench before you know this will take a bit of effort and may be hard to watch the dial.  The answer is in the Warren and Brown deflecting beam torque wrench part number 332600. This has a really neat feature where when you reach the proper preset torque, the deflecting beam hits a pin that lets a slide pop out and makes a noise.  This way you can see and hear that the proper torque has been reached.  CDI – (split beam link) and PI (Split beam link) also make a deflecting/split beam wrench within this capacity but they have internal wheels that must be set and this makes me feel more like the old click style although I know they are not.  Sent Warren and Brown an email to see if they will ship to the US as they are in Australia.  Ordered the other two dial CDI wrenches from ToolsDelivered.  I know all of this is way overkill but I am intent on taking a “turn till it snaps approach” into perfectly torqued fasteners.

EDIT: 03/14/2018  Wilmington Instruments Co. of Wilmington, CA is an importer of Warren and Brown products.  They have many in stock but as luck would have it they did not have any of the new ratcheting head units in inventory.  2-3 weeks and it will have arrived in CA from Australia.  Wilmington would not drop ship as they calibrate the units prior to delivery to the customer.

CDI Dial Torque Wrench Product List

 Authorized CDI Online Re-Seller List  ( had the best price when I searched the approved online list)-

Vans Torque Values (page 20 of 36)