Author Topic: Torque wrench for ER nuts DIY?  (Read 1011 times)

Offline PekkaNF

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Torque wrench for ER nuts DIY?
« on: July 27, 2019, 05:07:04 AM »
Yes, there are some expensive ones and they are available.

Yesterday walked into a bar shop and saw economical 3/8" torgue wrench. Pretty ideal size for ER25 nuts. How hard it can be to mount ER wrench to it?

Took it home and started measuring stuff - it's not actually that easy to fit it and retain same moment arm than the original setup. it would be really nice to keep the moment arms same and retain scale reading and not to decrease orginal max. setting torrque.

Bit more fiddling and if parts are cut right places and welded together, it would work. A) does this sort material weld well with the stick? I am pretty sure that the rachet mechanism part is scrap iron that contains maganese B) It actually would be nice if the head would me interchangeable, I may need some day a hook spanner or such exotic keys.

Suggestions?

Offline awemawson

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Re: Torque wrench for ER nuts DIY?
« Reply #1 on: July 27, 2019, 08:01:22 AM »
The axis of the ER nut obviously has to align with the axis of the Torque Wrench click bit to retain the same range of settings. I'm not sure how you are going to manage that AND have a tool in the ER collet  :scratch:
Andrew Mawson
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Offline PekkaNF

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Re: Torque wrench for ER nuts DIY?
« Reply #2 on: July 27, 2019, 08:25:17 AM »
hack off most of the rachet bell and stick glue remainers of the ER wrnech in place?

I have several torque wrences and I could cut one to pieces to make something more apropriate.

I have been measuring a little, and it would be possible to make the end piece (ER-wrench part) removable with pin/bolt joint, but looks like I'm going to settle welded seam here. Not too much space really if I wnat to keep the moment arms same as original.

the 90 degree figure and and stacked parts were just to show relative positions before I start cutting un-necessar parts off.

Offline Pete.

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Re: Torque wrench for ER nuts DIY?
« Reply #3 on: July 27, 2019, 10:33:14 AM »
Seems to me it will work pretty accurately the way it is shown so long as the torque wrench square is in line with the centre of the ER wrench handle. I welded a socket onto a home made face pin wrench to do up spindle bearings recently on this principle.

Weld a socket square to the ER handle and make sure the home-made crow's foot adapter is 90-degrees to the torque wrench handle. That's how they work, the distance is unimportant all that matters is they are dead square to each other.

Seems to me it will work pretty accurately the way it is. If the torque wrench square was in line with the centre of the ER wrench then it would always work correctly so long as the home-made crow's foot adapter is 90-degrees to the torque wrench handle. That's how they work.


Offline PekkaNF

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Re: Torque wrench for ER nuts DIY?
« Reply #4 on: July 27, 2019, 10:55:03 AM »
yes. nice video. Wish I had that teacher.

The 90 degree mod works. But on sertain positions you need two hands and vertical millin spindle, where key wants to fall off is hard enough, then you need another key that takes spare hand ans if you have a loose ER-key offset at 90 degree angle, it feels too much complication.

I have been milling estra stuff out, a little more to go. Damn hot, need to wait that I get a little shade on my welding place. Cofee break.

Offline PekkaNF

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Re: Torque wrench for ER nuts DIY?
« Reply #5 on: July 27, 2019, 04:51:24 PM »

It works.

I need to tack weld it three times, because I rushed and had rare case of over confidence with welding...made nasty scars. The final weld worked pretty well, should have left how they were, but desided to tidy them a little bit and they became even more ugly. Should I see a pattern here?

Pekka

Offline Will_D

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Re: Torque wrench for ER nuts DIY?
« Reply #6 on: July 27, 2019, 05:35:50 PM »
Why on earth would you want to torque an ER collect to some "defined" limit?

The wrenches supplied allow the user to tighten them "enough"

Now its a totally different situation in critical engineering situations like:

Ford Escort Head bolts or

Formula 1 car engine big end cap bolts etc

Or some safety critical bolt in a thermonuclear torus reactor
Engineer and Chemist to the NHC.ie
http://www.nationalhomebrewclub.ie/forum/

Offline PekkaNF

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Re: Torque wrench for ER nuts DIY?
« Reply #7 on: July 28, 2019, 05:44:34 AM »
Turns out that most people have no skill when it comes to olt torque, sometimes that is not that important sometimes it is critical. Most parts (outside of the engine) on E.G. lawnmover are not bolted with defined torque and then it does not matter. Modern cars and motobikes pretty much all matters. E.G. some Ford engines have spark plugs that have a tapered seat. Nearly 100% of DIY mechanics do it wrong and nearly same amount of skilled mechanics that don't use torque tools. This has caused many problems and net is flooded with videos where people swear at "stupid" sparkplugs that seize/rust up and broken threads.

Another problem is wheel/rim torque. Most people just don't get it right by feel. Many will get away with it, but this year I have helped three friends to open up the wheel bolts. One was solved with brak bar, another needed an penumatic impact wrench and last one need to weld 3/4" socket onto special bolt (After two diffeent garages tried to open it and broke two special keys). Yes aluminium rim, taper head bolt and tamper proof bolt, guy who tigtened it said that he did not use torque wrennch or too much force.....there was  nothing wrong with the bolt or anything, just too much uumph.

Now to this project.....I have measured TIR of various ER chucks and collets. Ebay ones are pretty much lottery....Individual parts may have TIR from almost acceptable to nearly 0,1 mm of TIR. I have thrown worst out and use marginal (0,02-0,03 mm of TIR per standard) for less demanding aplications or "specials" like scored drill shanks. The ones from reliable vendors or western brands (that has not moved manufacturing to low cost countries) seem to work fine. I have bought half a dozen MT3/ER25 cheap collet chucks. One is good, two marginals and rest ready to bin. All brand ones were good as they arrived.

I have noticed that torgue has effect on some chucks/collets. Pretty convinced that on cheap chucks the nut is often problem and some collets are faulty in every way.

Good collets/chuck seem to work on almost any torque setting, bad ones on none. There is a little indication that carbide mills are more sensitive to TIR and bad tool holding. I have broke few 3-5 mm carbide mills, some of them dumb errors, some of them left me buzzled.

Why does TIR matter? If you take very small carbide mill (or one with acure abgle like a grooving bit) the excessive eccentricity might cause your four flute mill to work as a fly cutter. Hand feed on the mill is uncertain and I always try observe the chips to see if they are anything near that they should be. With new (to me ) tools I use cutting tool feed/speed calculations to find out that a) mill has very limited top speed (somewhre a little over 2000 rpm) and b) with the small mills tooth load will cause pretty slow feeds. Now, if only one tooth cuts, that produces oversize groove and feed/speed calculation tooth load will quadrupled.

Now I have a means of torquing the ER collet nut to same torque (small mills I am aiming well below recommeded torque), plan is to check if somewhere 50% of max. torque value is good for small carbide mills that has smooth and hard shanks.

This has been checked in industry, there it has definate effect, maybe there is some truth in my home work shop where I have inferior tools and I don't have best practices. But I am workng to improve.

Maybe it is cost effective, maybe not. So far spent: 25 on torque wrenc, 5 or ER 25 wrench, few hours on garage and maybe this helps me to weed out bad tool shopping from good ones. Least I know now how to mod torque wrench for hook spanner and such, if I ever need to rebuild machine tool spindle.

Offline Joules

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Re: Torque wrench for ER nuts DIY?
« Reply #8 on: July 28, 2019, 06:08:33 AM »
Well this thread is a bit of a coincidence.  I have been working on a small torque driver using 3D printed parts.  It's main purpose will be for fasteners going into plastic.  Too easy just to nip up a fastner till you feel it pull, at which point you have over stressed the threads.  Some newer parts being made here are using a resin printer and the fasteners can be tiny and the resin print quite brittle.  Hence the design in progress for my Yankumtiter torque driver.

The use of 2mm ball bearings (as I have a few) are the hard sliding parts, one set fixed in the lower print, the top set tensioned by springs.  This design also allows for left or right tensioning, still further work in the design but this should fit into a normal screwdriver sized handle.   I can very much sympathise with the wheel nut fiasco.  I swap wheels over summer winter and have a large torque wrench for the wheel nuts.   Very annoyed when the car is serviced or tyre change and they just use the impact driver to put the nuts back on....

Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline PekkaNF

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Re: Torque wrench for ER nuts DIY?
« Reply #9 on: July 28, 2019, 09:37:34 AM »
That looks nice. Please tell how it comes together and works.

I have few torque screw drivers. I was afraid to break insert screws inside the tool holders....turns out that I was way gingery with insert hard screws and way too hamfised with normal screws, specially on aluminium and many small screws. It is really an eye opener what 1,2 Nm means.

this type:


I have three that cover pretty much all I need. At 50 a piece (after walking out twice from the tool store) they are not that cheap, but not nearly at kings ransom regime either. Warning: these have limited working life, but I have not met it yet after 4-5 years of hobby use.

On wheel bolts with impact wrences garages suhould use torgue limiting extensions "sticks", this is pretty good in general, and gets to point halfway:

More ramblings and some information:


Pekka

Offline PekkaNF

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Re: Torque wrench for ER nuts DIY?
« Reply #10 on: July 30, 2019, 05:01:24 PM »
Torque wrences multiply :lol:

I posted this build on Finnish site and I was offered bunch of industrial torque wrences that can be set to certain value and retain it pretty well and really long time.