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Car Forum / Honda Cars / December 2008Tegger: Craftsman Torque Wrench writeup
Nice writeup on opening your old torque wrench. Is it right that the upper nut in the handle was held in place by the plastic molding of the handle? So there is less chance of it rotating out of place than the lower nut? Also, didn't exactly see where the detent feels come from. I guess from the plastic lock ring area? The Lowe's Kobalt torque wrenches are also made by Danaher, but do carry a lifetime warranty. johngdole@hotmail.com wrote in news:7d23d43d-aed8-42ad-824b- 3be97cd2a29d@q30g2000prq.googlegroups.com: > Nice writeup on opening your old torque wrench. > > Is it right that the upper nut in the handle was held in place by the > plastic molding of the handle? So there is less chance of it rotating > out of place than the lower nut? The upper and lower nuts together clamp together the handle and the threaded shaft. This is how the wrench maintains its calibration. The handle and the shaft MUST NOT ever come out of phase. The upper nut does indeed sit in a matching hexagonal recess in the handle. Unless the handle should pull down sufficiently to allow the hex recess to come fully away from the upper nut, the nut and handle will stay in phase. However...if the lower nut comes loose, the upper nut will be loose as well, and will rotate relative to the threaded shaft (coming out of phase), throwing calibration off, which is exactly what happened to me. > Also, didn't exactly see where the detent feels come from. I guess > from the plastic lock ring area? If you look closely at the bottom of the wrench's body, you will see a series of long, shallow slots milled into the body. These are oriented axially, and spaced radially, around the body. (If they were cut all the way through, they would make the bottom of the body resemble a military rifle's flash suppressor.) There is a small nib, or protrusion, on the inside top of the plastic handle that indexes into the slots. When you turn the handle, its top flexes sufficient to allow the protrusion to ride out of one slot and fall into the next, giving the handle that "click" feeling as you wind the setting up or down. There are ten slots, of course, one for each pound as you rotate from 1 through 0 up each ten pounds of scale marking. I'm not sure how the locking ring functions; it never occurred to me to examine that assembly. > The Lowe's Kobalt torque wrenches are also made by Danaher, but do > carry a lifetime warranty. That's interesting. Sears' "lifetime" warranty essentially only covers tools without moving parts, so the torque wrench is not covered.  SignatureTegger The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ >> Also, didn't exactly see where the detent feels come from. I guess >> from the plastic lock ring area? I've updated the relevant page on the site to clarify handle "click" operation. You may have to hit Refresh/Reload in your browser to see the changes. SignatureTegger The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ >>> Also, didn't exactly see where the detent feels come from. I guess >>> from the plastic lock ring area? > > I've updated the relevant page on the site to clarify handle "click" > operation. You may have to hit Refresh/Reload in your browser to see the > changes. Interesting info on torque wrenches. I have an old Sear beam type --seldom used any longer -- and have often wondered how accurate it is. Unless abused or damaged in some way, I should imagine a beam type would hold its accuracy over a long period of time or perhaps the life of the instrument? >>>> Also, didn't exactly see where the detent feels come from. I guess >>>> from the plastic lock ring area? [quoted text clipped - 14 lines] > hold its accuracy over a long period of time or perhaps the life of the > instrument? bending beam offer the best accuracy/price ratio. their main drawback is not being able to see the dial in all orientations, but other than that, they're great. they can have advantages on things like cylinder heads too because you can torque and hold - essential when dealing with a blind bolt hole where lube is slowly squeezing out and would otherwise give a false torque reading. tilt-block type torque wrenches are notoriously difficult to keep in calibration. split beam wrenches are accurate and robust and don't have any of the tilt-block drawbacks because nothing is loaded when not being used - they tend to be much more expensive though. > tilt-block type torque wrenches are notoriously difficult to keep in > calibration. split beam wrenches are accurate and robust and don't > have any of the tilt-block drawbacks because nothing is loaded when > not being used A tilt-block wrench also has no loaded parts when not in use, provided you dial it back down after use. SignatureTegger The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ >> tilt-block type torque wrenches are notoriously difficult to keep in >> calibration. split beam wrenches are accurate and robust and don't [quoted text clipped - 3 lines] > A tilt-block wrench also has no loaded parts when not in use, provided > you dial it back down after use. not as simple as that. one of the reasons there is a problem with calibration issue with tilt-blocks is because virtually all manufacturers use polymers in construction. http://www.tegger.com/hondafaq/torque_wrench/exploded_view.jpg the polymers in the actual tilt block unit are subject to "relaxation". if you set the spring and measure torque at 10 seconds, 30 seconds, 60 seconds, 2 minutes, 5 minutes and 10 minutes, [etc] you'd get a progressively lower torque trigger reading every time. a load path that only loads momentarily and when in use, like you have with split beam, doesn't have that problem. >>> tilt-block type torque wrenches are notoriously difficult to keep in >>> calibration. split beam wrenches are accurate and robust and don't [quoted text clipped - 14 lines] > 30 seconds, 60 seconds, 2 minutes, 5 minutes and 10 minutes, [etc] > you'd get a progressively lower torque trigger reading every time. Hm. I wonder by what amount? SignatureTegger The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ Tegger <invalid@invalid.inv> wrote in news:Xns9B68493394280tegger@ 208.90.168.18: >> http://www.tegger.com/hondafaq/torque_wrench/exploded_view.jpg >> [quoted text clipped - 4 lines] > > Hm. I wonder by what amount? I just had a close look at the picture you referenced, plus my original photos. I'm pretty certain the item I call the "anti-windup assembly" only had a skin of polymer around the outside as a cage, serving only to hold the ball bearings in place. The assembly itself was steel all the way through to the bottom where the spring bore against it. This wrench has no polymer load-bearing parts. SignatureTegger The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ > Tegger <invalid@invalid.inv> wrote in news:Xns9B68493394280tegger@ > 208.90.168.18: [quoted text clipped - 17 lines] > > This wrench has no polymer load-bearing parts. if that's the case, it's ok to leave it "loaded" when not being used. if there's any polymer, you have to unload it. >> Tegger <invalid@invalid.inv> wrote in news:Xns9B68493394280tegger@ >> 208.90.168.18: [quoted text clipped - 21 lines] > if that's the case, it's ok to leave it "loaded" when not being used. > if there's any polymer, you have to unload it. The manual says you must dial it down to no more than 20% of capacity if letting it sit for an extended length of time. This suggests that leaving it at a higher setting will result in permanent distortion of the spring's steel. I'm paranoid enough to want to take /all/ the load off the spring when storing the wrench, so I bring it down all the way. SignatureTegger The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ Is it correct that both ends of the "anti-windup" mechanism actually rotate with respect to each other? Because it looks like the ball bearings help reduce friction so all tension from the spring transfer to the tilt block/ratchet head. If so that would be the "interface" mentioned in US Patent 5,503,042. "freely rotatable cylindrical roller" it says. Not too flashy. Or, similarly, as the following web site calls it "interface mechanism (toggle, cam or low-friction roller)" http://www.buyerzone.com/construction/rbic-torque-wrench.html > I'm pretty certain the item I call the "anti-windup assembly" only had a > skin of polymer around the outside as a cage, serving only to hold the ball [quoted text clipped - 7 lines] > > The Unofficial Honda/Acura FAQwww.tegger.com/hondafaq/ Another one: US patent 7451674, http://www.patentgenius.com/patent/7451674.html calls it "spring and pawl". So the "bar" of the ratchet head rests on the "pawl". Which I guess is the tilt block + roller interface. Then comes the spring. (Ratchet bar -> Pawl -> Spring.) Now Harbor Freight ads say: heavy duty cam and pawl mechanism. I guess the ratchet bar is considered the cam then that rests on the pawl mentioned in patent 7,451,674?? Excerpt from US Patent 7,451,674: "The most popular type of this wrench is called a micrometer torque wrench and has a hollow arm which includes a spring and pawl mechanism for setting the torque. Within the hollow arm, the pawl is forced against one end of a bar that is connected to a drive head, the bar and a drive head are pinned to the hollow arm and rotate as torque is applied. The pawl is released when the force applied by the bar increases beyond a set value established by the operator. When released, the bar hits the inside of the arm, producing a sound and a distinct feel by a user. The torque value or release point is changed by rotating the handle, which moves on threads for setting. Additionally, values are permanently stamped or imprinted on a scale that is located on an outer surface of the hollow arm. Micrometer wrenches can overtorque when the operator continues to apply pressure after release, due to the momentum created by the releasing mechanism. This overtorque may occur without the user even realizing it. " > I just had a close look at the picture you referenced, plus my original > photos. [quoted text clipped - 10 lines] > > The Unofficial Honda/Acura FAQwww.tegger.com/hondafaq/ Here is another picture of the tilt (or pivot) block in a cut-away view: http://www.motor.com/article_pdf_download.asp?article_ID=599 The torque wrench should be kept in the lower 25% of the range when not in use (according to Danaher), but the Motor.com article suggests no less than the minimum on the torque wrench in case the tilt block dislodges! I'm sure with all trade publications (or TV/movies these days) there will be plenty of unashamed advertisements. Just read past them I guess. However, Tegger could have recalibrated his old torque wrench for $25 + shipping with Angle Repair, if he missed last Friday's 50% off Craftsman torque wrenches! ;) ;) ;) > not as simple as that. one of the reasons there is a problem with > calibration issue with tilt-blocks is because virtually all manufacturers [quoted text clipped - 9 lines] > a load path that only loads momentarily and when in use, like you have > with split beam, doesn't have that problem. I didn't think of it earlier, nor did I expect Sears Parts Direct to sell every single part in their Danaher-made torque wrench. Here it is Tegger, the description of every part in that torque wrench: Turns out the "pawl" is the tilt block, the "anti-windup" assembly Tegger mentioned is the cam assembly. The Sears version of the Danaher torque wrench seems to have a weak handle lock ring that breaks often. The SK and Lowe's version use a metal lock ring. If the plastic ring breaks and people still want a Craftsman, it's cheaper to buy a new wrench during 50% year-end-sale than to buy a new handle and send it in for calibration ($25 + round trip shipping). Who knows, people may even be able to substitute a SK or Lowe's handle. Sears Danaher-made torque wrench parts drawing: http://c.searspartsdirect.com/lis_png/PLDM/P0111046-00001.png The torque wrench has: ---------------------------------- Ratchet assembly Dust Seal Arm pin/retaining ring Barrel Pawl (tilt block) Cam assembly (cam, cam spring, cage, balls) R. nut pin (??) Torque spring Spring cup Positive engagement spring Thrust washer Adjusting screw assembly (ball, adj screw, round nut, handle nut) Grip assembly Handle nut End cap On Dec 3, 12:32 am, johngd...@hotmail.com wrote: > I didn't think of it earlier, nor did I expect Sears Parts Direct to > sell every single part in their Danaher-made torque wrench. Here it is [quoted text clipped - 32 lines] > Handle nut > End cap yep, one more victim of the busted plastic sears lock ring here. otherwise, seems to be a decent wrench. i busted the ratchet out of a cheaper wrench previously, still works OK despite the busted lock ring, you just have to be careful not to twist the handle. any day now i've been planinng to wrap the lock ring with a screw type hose clamp, that oughta hold it. Yeah, the detents should help hold the readings. The Sears version of the Danaher-built wrench is probably the cheapest one they make (especially during the 50% off sale), then come the Lowe's/SK and GearWrench/Armstrong/Matco (3% accuracy). All from Danaher of course. After reading Tegger's detailed description, I'm confident that if needed you can order a handle from Sears (~$8 plus shipping) and recalibrate it yourself (home-garage-grade calibration, of course). Or better, change to a Lowe's or SK style handle except I'm not sure where to get them (maybe Angle Repair?). I would use a beam type to baseline the readings of your wrench at 30% and 60% max torque (or more points), and measure the protrusion of the adjusting bolt, similar to how you would a brake master cylinder push rod. Adjust the bolt so you get minimal torque differences at those points, well approximately anyway. It shouldn't be that difficult (with the proper thin-walled socket and allen wrench) because one adjusting bolt means linear adjustment, right? Now, Tegger may be able to get that torn-apart wrench back into service...... ;) ;) ;) > yep, one more victim of the busted plastic sears lock ring here. > otherwise, seems to be a decent wrench. i busted the ratchet out of a [quoted text clipped - 3 lines] > careful not to twist the handle. any day now i've been planinng to > wrap the lock ring with a screw type hose clamp, that oughta hold it. johngdole@hotmail.com wrote in news:e887a944-611e-4817-ba5b-601bc857da04 @q26g2000prq.googlegroups.com: > Yeah, the detents should help hold the readings. The Sears version of > the Danaher-built wrench is probably the cheapest one they make [quoted text clipped - 17 lines] > Now, Tegger may be able to get that torn-apart wrench back into > service...... ;) ;) ;) I wish! It's in the town dump somewhere by now. I tossed it during a housecleaning soon after doing the intial writeup. And hey, it's been a while, but I finally got your contributions up on the torque wrench page. http://www.tegger.com/hondafaq/torque_wrench/index.html Thanks very much. SignatureTegger The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ <snip> I'm gonna answer all your post in this one reply. My goodness you've been productively busy, and I thank you very much. The contents/intent of your recent posts here will eventually make it into the torque wrench page. I'm just not sure quite when. SignatureTegger The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ Thanks for the detailed explanation. I see the slots now. Looks like I'll be putting some threadlockers in mine to help keep the lower nut in place, as it's not worth it for me to send it in for calibration. $25 plus shipping both ways will cost the same as a new wrench with the annual sale, and I don't need a laboratory-grade certification. I wonder if the detents have something to do with the high rate of complaints about the plastic lock ring breaking (the Kobalt uses a metal ring without detents). I suppose if the lock ring isn't loosed up fully before adjusting, the force of turning will be transferred to the plastic ring. At least that's what I supposed will hold the setting when "locked". I was at Lowe's earlier, their Danaher-made torque wrenches say no hassle lifetime in big letters under the brand name "Kobalt", but the same 90day/1year in fine print as Sears. Oh well, until I get a $400 Snap On I guess. Thanks again! Among the excellent articles, torque wrench calibration on motor.com: http://www.motor.com/article_pdf_download.asp?article_ID=516 > johngd...@hotmail.com wrote in news:7d23d43d-aed8-42ad-824b- > 3be97cd2a...@q30g2000prq.googlegroups.com: [quoted text clipped - 45 lines] > > The Unofficial Honda/Acura FAQwww.tegger.com/hondafaq/ > Among the excellent articles, torque wrench calibration on motor.com: > http://www.motor.com/article_pdf_download.asp?article_ID=516 Thanks for the link. I've added it to the page. SignatureTegger The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ On Mon, 24 Nov 2008 17:25:21 -0800, johngdole wrote: > Thanks for the detailed explanation. I see the slots now. Looks like > I'll be putting some threadlockers in mine to help keep the lower nut in [quoted text clipped - 16 lines] > Among the excellent articles, torque wrench calibration on motor.com: > http://www.motor.com/article_pdf_download.asp?article_ID=516 looks like a [not so] thinly disguised advertising article to me. >> johngd...@hotmail.com wrote in news:7d23d43d-aed8-42ad-824b- >> 3be97cd2a...@q30g2000prq.googlegroups.com: [quoted text clipped - 46 lines] >> >> The Unofficial Honda/Acura FAQwww.tegger.com/hondafaq/ The only other breakdown diagram of a torque wrench I find is the Harbor Freight 1/2" clicker. Hand drawn and not properly named parts. The operations aren't as smooth as the Danaher, but the last time I checked it was very close. Really not bad for a $14 on sale torque wrench. Guess it's time to borrow a beam type. http://www.harborfreight.com/manuals/0-999/239.pdf johngdole@hotmail.com wrote in news:da7510a5-3887-4060-8f71-04504977c898 @q26g2000prq.googlegroups.com: > The only other breakdown diagram of a torque wrench I find is the > Harbor Freight 1/2" clicker. Hand drawn and not properly named parts. [quoted text clipped - 3 lines] > > http://www.harborfreight.com/manuals/0-999/239.pdf That diagram is pathetic. My 11 year-old daughter could make a better one. SignatureTegger The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ |
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