PSA - use a torque wrench to tighten the bands... and how to eliminate under/overbite?

caliking said:

The torque wrench was bought for the egg,  so I'm ok with it not being super accurate. 

@johnnyp -  I'll post a pic in a little bit. You need to crank those bolts tight, or your bands could slip. Trust me,  you won't crack the dome or lid by tightening the bolts. The force is distributed evenly around the circumference of the lid and dome

'Super Accurate' is indeed, one thing.
But what matters is if it is REPEATABLE or not.  Torque 10 bolts, or ONE bolt 10 times over a period of time.   The actual torque applied should be within maybe 5% or so.   On a 10ft/lb torque, I'd accept +-10% at worst.  

I have NO idea other than paying for a calibration, just HOW to check a torque wrench.  
I had a 3/4" (yes, 3/4") used at work MANY years ago.   It was a Proto 'click-stop' and fairly expensive.   It was sent out ANNUALLY for certification.  It was important that the wrench be right.  Even after instruction, the guy who took my place RUINED it in a matter of a couple months after I moved on.  

Having an accurate torque wrench when one is called for is certainly a necessary tool.  Rebuild an automobile engine and accurate torques are a requirement for engine longevity.  The bolted joints on an engine are machined so that the washer flats and bolted surfaces are perpendicular to the bolt holes to eliminate bolt bending.   Even with a "perfectly" machined bolted joint, some of the torque goes into overcoming thread and bolt head friction ... and torque-to-load results are affected by thread smoothness, oil, dirt, etc.  Very accurate bolted joints use a torque-turn method to reduce the affects of those variables... torque to low setting to snug the joint and then turn the bolt through a specific angle.

Having said that, the band bolt arrangement on our eggs is a crude mechanism at best.  Nothing is parallel, the bolts bend, the band tabs bend and the nut gouges a grove in the band tab.  For accurate, repeatable loading it's a nightmare.  If you don't have a natural feel for loads on a wrench, then an inexpensive torque wrench dedicated to checking the torque on your egg is okay.  Torquing to +/- 20 % is better than a "I think that's tight enough" guess.   

For the EGG, I'll GLADLY sacrifice Accuracy for Repeatability.  

Jeepster47 said:

Having an accurate torque wrench when one is called for is certainly a necessary tool.  Rebuild an automobile engine and accurate torques are a requirement for engine longevity.  The bolted joints on an engine are machined so that the washer flats and bolted surfaces are perpendicular to the bolt holes to eliminate bolt bending.   Even with a "perfectly" machined bolted joint, some of the torque goes into overcoming thread and bolt head friction ... and torque-to-load results are affected by thread smoothness, oil, dirt, etc.  Very accurate bolted joints use a torque-turn method to reduce the affects of those variables... torque to low setting to snug the joint and then turn the bolt through a specific angle.

Having said that, the band bolt arrangement on our eggs is a crude mechanism at best.  Nothing is parallel, the bolts bend, the band tabs bend and the nut gouges a grove in the band tab.  For accurate, repeatable loading it's a nightmare.  If you don't have a natural feel for loads on a wrench, then an inexpensive torque wrench dedicated to checking the torque on your egg is okay.  Torquing to +/- 20 % is better than a "I think that's tight enough" guess.   

Thanks Tom! I am surrounded by retired CAT engineers who seldom can explain ANYTHING in English. You, Sir, are a living credit or perhaps an anomaly to your profession! 

Begger said:

... I have NO idea other than paying for a calibration, just HOW to check a torque wrench.  ...

@Begger ... for the accuracy we're interest in achieving that's somewhat of an easy proposition.

1) Find someone with a small torque wrench that you trust.  Compare yours against theirs.

2) The Harbor Freight torque wrench looks to be 11 inches long.  Mark nine inches from the center of the socket on the torque wrench.  Set the wrench at 120 inch lbs and put the wrench on a bolt/nut such that the wrench is parallel to the ground ... clamping the 1/4" end into a vise will also work.  Tie a small diameter rope around a 13.5 lb weight (a pail of water will work) and hang the rope on the torque wrench handle at your mark.  13.5 lbs at 9 inches calculates out to 121.5 inch lbs of torque ... close enough for government work.  You want the wrench to click "just" as the last of the weight is applied to the wrench.  Adjust the wrench until you achieve that result.  The wrench is now "calibrated" for 121.5 inch lbs.

That's a GOOD idea and very repeatable.     I'm LESS concerned with the absolute number than getting it pretty much the same each time.

But this way, I can have it BOTH ways.   I think you could work something out with a breaker bar, too.  

caliking said:

@johnnyp - Sorry for the delay. Had a bunch of stuff going on today. Here is a pic of my now-bent bolts.

My bolts are bent more than this and my egg has a underbite ....personally I think it's just poor design.
I did use a torque wrench as well but it never stopped my bands from slipping albeit they seem pretty snug right now but I havnt done a high temp cook in awhile.