Micrometer Info - And Other Key Tools

[senseamidmadness]

As a novice hobby machinist I appreciate this thread.

 

[Omega Man]

More tools here- https://forums.bmwmoa.org/showthread.php?101441-Your-favorite-tools

OM

 

[MCMXCIVRS]

I am having a tough time understanding that because the spring in the length of the handle is pre-loaded for a certain torque. Now if I grab it at the handle or 50% of the way from the pivot, I cannot see how that makes a different in that the whole length of the handle is being moved and the spring pre-load does not change as to where I hold it.

I would need a diagram showing how the insides work.

I'm with you. The video with all the math makes it seem very smart, but it entirely overlooks the fact that the handle is a solid tube and applies the force to the click mechanism at the same exact length no matter where the handle is gripped. The force applied is transferred through the length of the solid handle tube to the mechanism the same no matter where you are holding it. That's the great thing about these type of torque wrenches, they virtually eliminate the user error and allow consistent results no matter how awkward the position or location of the fastener is to get at. That said, I can't see any reason to choke up on the handle and make the work harder than it needs to be.

One thing I was taught about a click type torque wrench is that you must always fully back off the adjustment when not in use so as to not weaken the spring tension over time by storing it compressed.

 

[robsryder]

Here is a video that illustrates the operation of a dial-type torque wrench with an indicator light. This unit is very similar to those sold by Snap-On. The company no longer appears to sell this item. Sellers of surplus items seem to want a price similar to that for the Snap-On unit (lots of $$$!).

https://www.neobits.com/dmc_bt_st_751_daniels_manuf_corp_bt_st_751_p8737528.html?atc=gbs

Here is a link to a Precision Tools dial torque wrench with an indicator light (what a bargain at about half the price of a Snap-On unit!)
https://www.toolsource.com/dial-wre...38-in-dr-dial-torque-wrench-w-in-p-93091.html

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[globalrider]

Take a look at the video with the mathematical physics explanation. I needed to follow that math to "get it".

Well that now makes sense knowing how "clickers" are constructed, although as I use my "clickers" it was never an issue. Good to know though.

Same thing for the cheap beam type with the long pointer where it does make more sense because the pivoting handle is on a pin and the ends of the pivoting handle should not touch the beam when applying force.

 

[globalrider]

That said, I can't see any reason to choke up on the handle and make the work harder than it needs to be.

Exactly, why would you?

As for these "electronic" torque wrenches, I would not buy one. When I bought my 1/4" "clicker" torque wrench from Snap-On, months later the dealer wanted to buy it back for what I paid for it and sell me one of those electronic jobbies. No thanks. I do not need a battery and I have to wonder how long the strain gauge will stay bonded in place. KISS = Keep It Simple Stupid.

 

[robsryder]

Here is another video showing some testing of an inexpensive HF click-type torque wrench. A non-scientific abuse session with the torque wrench follows by more testing. It was interesting as to the robustness of this wrench. I would strongly advocate against misuse of one's tools, particularly a torque wrench.

Also of interest was the use of a relatively inexpensive digital torque adapter as a test device. I am considering use of a similar device to check the functionality of my torque wrenches. I believe that most Snap-On trucks have a genuine torque wrench tester (although when I last visited a truck the tester lower limit was 25 ft-lbs). If one visits the Snap-On truck, be warned that you might exit with some additional tools!!

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[robsryder]

Following is a screen shot of the results from a test of the HF digital torque adapter. The whole test video follows. [The CDI / Snap-On torque tester is also very nice but way more expensive than I want to pay! ]




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[88bmwjeff]

Thanks to all who have provided and commented so far. I've learned more than I've thought I needed to know about these tools. But, it's been educational and I've appreciated it.

Thanks again.

 

[robsryder]

I was very interested to watch some of the disassembly videos of the click-type of micrometer torque wrenches. I also was interested in the dial-type of torque wrenches, but the price of the Snap-On units is quite high. The items from Precision Instruments are less expensive; from their website it appears as though they may make these (just outside Chicago) for Snap-On and their prices are lower. Even less expensive are some offerings from Chinese companies.
https://torqwrench.com/

I decided to obtain one of the much less expensive dial-type torque wrenches. See link below -
https://www.amazon.com/gp/product/B078MHYBB7/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

This less expensive unit (0 to 10 N-m) was advertised as having a 3% accuracy. I tested this against a 1/4-inch drive digital torque adapter which I had earlier checked against some weights and found to be pretty accurate (couple of percent). [Note: I am not trying to be a metrology lab, and my checking involves placing weights at a distance along an arm (ratchet) with the angle maintained as close to a right angle as I can. The torque adapter is horizontal clamped in a vice, but in addition to the rotational moment placed to check the torque, there is another moment at an orthogonal angle (due to the torque adapter sticking out of the vice.) Thus, it is necessary to hold the torque adapter whilst trying to place the weights on the ratchet arm. Saying that I get a couple of percent accuracy could be optimistic.] But, for my purposes I concluded that the torque adapter was "accurate" and would be my standard to check other torque wrenches.

A photo of the torque adapter is shown below. The particular device was packaged by Bike Master and purchased through the 'Zon (currently this unit is shown as no longer available).

In my testing of the inexpensive dial-type of torque wrench against the digital torque adapter I found the measurements to be more than 5% off. Instead of returning the torque wrench to Amazon, I thought that I would investigate the mechanical operation of this device. Shown are photos of the top of the dial-type torque wrench (screws have already been removed). Next is a side view where the tension arm is connected to an adjustable rod that is in a slot that drives a watch-like mechanism to move the dial indicator. The third view is of the bottom of the mechanism. Shown are a couple of screws that affix the rod that fits into a slot moving the dial. I determined the the movement back and forth of the rod (upon loosening the screws) would cause the sensitivity of the torque wrench to change. After a good deal of iterative fiddling about I was able to improve on the accuracy of the dial-type torque wrench. About 8.1 N-m on the dial produced 8 N-m at the torque adapter. There was similar agreement throughout the operating range. I declared victory. The torque wrench was re-assembled.

 

[Omega Man]

I was very interested to watch some of the disassembly videos of the click-type of micrometer torque wrenches. I also was interested in the dial-type of torque wrenches, but the price of the Snap-On units is quite high. The items from Precision Instruments are less expensive; from their website it appears as though they may make these (just outside Chicago) for Snap-On and their prices are lower. Even less expensive are some offerings from Chinese companies.
https://torqwrench.com/

I decided to obtain one of the much less expensive dial-type torque wrenches. See link below -
https://www.amazon.com/gp/product/B078MHYBB7/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

This less expensive unit (0 to 10 N-m) was advertised as having a 3% accuracy. I tested this against a 1/4-inch drive digital torque adapter which I had earlier checked against some weights and found to be pretty accurate (couple of percent). [Note: I am not trying to be a metrology lab, and my checking involves placing weights at a distance along an arm (ratchet) with the angle maintained as close to a right angle as I can. The torque adapter is horizontal clamped in a vice, but in addition to the rotational moment placed to check the torque, there is another moment at an orthogonal angle (due to the torque adapter sticking out of the vice.) Thus, it is necessary to hold the torque adapter whilst trying to place the weights on the ratchet arm. Saying that I get a couple of percent accuracy could be optimistic.] But, for my purposes I concluded that the torque adapter was "accurate" and would be my standard to check other torque wrenches.

A photo of the torque adapter is shown below. The particular device was packaged by Bike Master and purchased through the 'Zon (currently this unit is shown as no longer available).

In my testing of the inexpensive dial-type of torque wrench against the digital torque adapter I found the measurements to be more than 5% off. Instead of returning the torque wrench to Amazon, I thought that I would investigate the mechanical operation of this device. Shown are photos of the top of the dial-type torque wrench (screws have already been removed). Next is a side view where the tension arm is connected to an adjustable rod that is in a slot that drives a watch-like mechanism to move the dial indicator. The third view is of the bottom of the mechanism. Shown are a couple of screws that affix the rod that fits into a slot moving the dial. I determined the the movement back and forth of the rod (upon loosening the screws) would cause the sensitivity of the torque wrench to change. After a good deal of iterative fiddling about I was able to improve on the accuracy of the dial-type torque wrench. About 8.1 N-m on the dial produced 8 N-m at the torque adapter. There was similar agreement throughout the operating range. I declared victory. The torque wrench was re-assembled.

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Your a Wild Man!

OM

 

[The_Veg]

Back to micrometers, here's my anecdote about them.

Shim-and-bucket valvetrains seem to find me. My first mo'orsickle was a K100 and I've owned two Lotus cars that have shims and buckets. The current Lotus is half a century old and I've taken great pains to get its valves right. Lucky for me, in my day-job I use a 1" digital micrometer that gets calibrated annually, and being a remote-based field employee, my company tool-kit lives right there in my garage. I've caught a few shims purchased from respected sources that were incorrect.

 

[robsryder]

One of my key tools when I need to "see" what is going on electrically-

The Simpson 260.

https://simpsonelectric.com/products/test-equipment/vom-multimeters/260-8-260-8p/

OM

Following is a link to a video comparison between digital and analog volt-ohm-meters (VOMs). The reviewer has (in my view) an entertaining video blog and his position clearly favors the digital VOM. Of interest were the large number of comments that indicate a preference in some circumstances for the analog VOM. Sometimes it is because the old analog VOM belonged to a parent or grandparent. [This brings to mind some of the stories about folks keeping old airhead motorcycles for the same reasons ]

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[globalrider]

Of interest were the large number of comments that indicate a preference in some circumstances for the analog VOM.

Because analog meters have certain advantages to them. I have one, but I also have a slew of DMMs right up to a Fluke 88V Automotive Kit.

 

[elementist]

Because analog meters have certain advantages to them. I have one, but I also have a slew of DMMs right up to a Fluke 88V Automotive Kit.

Didn't watch the video did ya.

Care to extoll the benefits an analog would have over a modern digital these days?

 

[globalrider]

Didn't watch the video did ya.

Nope, I don't have all day. Besides, I worked in an electrical standards lab for many years.

Care to extoll the benefits an analog would have over a modern digital these days?

A modern DMM these days can swing between $10 to a nice Aglient 4-wire in the thousands. They don't have the same features and abilities.

Well for example, when I was testing a Bosch Air Flow Meter on a friends Porsche, I wanted to see a smooth increase in voltage (the needle moving smoothly) without seeing any dead spots as I slowly moved from idle to full throttle. Kind of hard to do with a digital meter. In another case where you have a fluctuating voltage, a digital meter doesn't do it unless you have Max and Min Hold and even then.

 

[Omega Man]

Didn't watch the video did ya.

Care to extoll the benefits an analog would have over a modern digital these days?

You would have to see the difference in actual operations to understand the difference in reaction times.

OM

 

[globalrider]

You would have to see the difference in actual operations to understand the difference in reaction times.

OM

Exactly.

BTW, I used to have fun with engineers that were in their last year or just graduated. Funny how people think when they see digits, how can you possibly go wrong.

So I gave then a simple DC series circuit (10V) with two 10M ohm resistors in it and asked them to measure the voltage from ground to the first resistor. Hey, why am I not seeing 5V. Well that is what happens when you don't understand measurement principles and understand how a measurement device can change reality.

 

[elementist]

I've used many versions of both, the video does a good job showing the digital sampling rate and accuracy beats the supposed benefits of an analog meter. In my experience it's been the same as the video, a good DMM will show you what you want more accurately and with less distortion and noise than any analog available in the sub $1000 consumer range.

A bad digital may be worse than a bad analog which is the only argument I've found truth to, but good digitals are common and easy to find.

 

[elementist]

Exactly.

BTW, I used to have fun with engineers that were in their last year or just graduated. Funny how people think when they see digits, how can you possibly go wrong.

So I gave then a simple DC series circuit (10V) with two 10M ohm resistors in it and asked them to measure the voltage from ground to the first resistor. Hey, why am I not seeing 5V. Well that is what happens when you don't understand measurement principles and understand how a measurement device can change reality.

I love working with old engineers. Many think they know everything.

My experience has been, both out of school decades ago and mid career there are two types of engineers.

Those that learn, and those that don't.

Those that learn keep learning. The tools and techniques change, and what is common knowledge now often goes against the wisdom of the elders.

I've spent a lot of time fixing stuff those more senior than me have, in their wisdom and experience,royally ****ed up. In fact I've made a bit of a career, a quite successful one of it.

I've worked with idiots right out of school and days from retirement. I've worked with people that taught me something that haven't graduated yet and have retired years ago. Learning is the key.

Funny in the video he covers the digital beating the analog at that test showing 4.97 vs 4 when you'd "expect" 5 naively running the math on the circuit.