Torque multiplier.
A Low Cost 300 ft-lb Torque Wrench - DIY Shop-Built (2 Viewers)
- Thread starter Bambusiero
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Bambusiero
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- Thread starter
- #23
3/4" Torque multiplier would be a handy gadget to have around, at times, no doubt. But they are fairly expensive too. ($230-ish)
Seems to me that one could adapt this "cheater bar" idea to make an adapter between the standard 1/2" torque wrench and the 3:1 torque multiplier head - could be much more compact, and yet high torque capable. Would need to compensate (some unknown amount like 90% ???) for frictional loss in the torque multiplier head.
- Yet another possible 300 ft-lb torque wrench solution - (at reasonable cost $80-ish) - 3/4" 150-750 ft-lb electronic torque sense head - with your 3/4" breaker bar.
Seems to me that one could adapt this "cheater bar" idea to make an adapter between the standard 1/2" torque wrench and the 3:1 torque multiplier head - could be much more compact, and yet high torque capable. Would need to compensate (some unknown amount like 90% ???) for frictional loss in the torque multiplier head.
- Yet another possible 300 ft-lb torque wrench solution - (at reasonable cost $80-ish) - 3/4" 150-750 ft-lb electronic torque sense head - with your 3/4" breaker bar.
Last edited:
My brain hurts!
I used this method previously to torque the crank bolt on my 1fz-fe.
I've since realised my torque wrench was reading 20% low.
I also have a digital torque adapter that can be used with any ratchet or breaker bar etc
I'm going to use this method again, but am second guessing the leverage ratio to make a torque extension .
The thing I'm stuck on is this. The torque adapter doesn't know if I have a 12" long handle on it, or a 24" long handle. Torque is read at the drive head.
If I add an extension lever, what length do I use to calculate a leverage ratio?
I'm assuming because its reading 100ftlb, I should use 12" for handle length. (I want to eliminate the assumption)
So, a 12" extension will give me a 2:1 ratio.
To achieve 300ftlb at the bolt with 12" extension force required on a 12" handle would be 150ftlb??
To achieve 300ftlb with 24" extension becomes 100ftlb of force on the handle?? 3:1 ratio?
I think I should be able to from with @Bambusiero original calculation on page 1.
Can anyone confirm this?
I can find plenty of calculators for this using old school torque wrenches, nothing for torque adapter head.
play.google.com
I used this method previously to torque the crank bolt on my 1fz-fe.
I've since realised my torque wrench was reading 20% low.
I also have a digital torque adapter that can be used with any ratchet or breaker bar etc
I'm going to use this method again, but am second guessing the leverage ratio to make a torque extension .
The thing I'm stuck on is this. The torque adapter doesn't know if I have a 12" long handle on it, or a 24" long handle. Torque is read at the drive head.
If I add an extension lever, what length do I use to calculate a leverage ratio?
I'm assuming because its reading 100ftlb, I should use 12" for handle length. (I want to eliminate the assumption)
So, a 12" extension will give me a 2:1 ratio.
To achieve 300ftlb at the bolt with 12" extension force required on a 12" handle would be 150ftlb??
To achieve 300ftlb with 24" extension becomes 100ftlb of force on the handle?? 3:1 ratio?
I think I should be able to from with @Bambusiero original calculation on page 1.
Can anyone confirm this?
I can find plenty of calculators for this using old school torque wrenches, nothing for torque adapter head.
Norbar Torque Wrench Extension - Apps on Google Play
Find what value you should set into a torque wrench.
So, it turns out, my torque adapter doesn't know what length handle is attached, or if an extension/crows foot/ dog bone etc is attached.
I spent some time mocking up some extensions and checking forces required on an extension to achieve set torque at the torque adapter.
With the handle side of the torque adapter held in the vice, no handle, and 12" extension in place of a socket, the gauge reads at 1:1. No torque multiplication.
(Also tested with a baggage scale that reads within a verified 2% at 5kg)
12" extension reads 50# on torque adapter and 50# on my scales.
A 24" extension reads at 2:1 50# at the torque adapter, 25# at the extension.
A 36' extension it was reading 3:1, or 17-18# with scales on the end of the extension, and 50# at the torque adapter.
I made up a 900mm extension using some 50x25mm RHS steel, and went and bought a couple of cheap impact sockets. Welded a 32mm socket in one end (I know, it should be 30mm
, but it's single hex, so I'm calling it good!)
Welded a 20mm socket in the other end to make use of the 1/2 drive. 20mm gave me a good circumference to put a weld around, and some meat around the 1/2 drive.
Gonna sit on this overnight, coz I'm second guessing my math still.
I spent some time mocking up some extensions and checking forces required on an extension to achieve set torque at the torque adapter.
With the handle side of the torque adapter held in the vice, no handle, and 12" extension in place of a socket, the gauge reads at 1:1. No torque multiplication.
(Also tested with a baggage scale that reads within a verified 2% at 5kg)
12" extension reads 50# on torque adapter and 50# on my scales.
A 24" extension reads at 2:1 50# at the torque adapter, 25# at the extension.
A 36' extension it was reading 3:1, or 17-18# with scales on the end of the extension, and 50# at the torque adapter.
I made up a 900mm extension using some 50x25mm RHS steel, and went and bought a couple of cheap impact sockets. Welded a 32mm socket in one end (I know, it should be 30mm
, but it's single hex, so I'm calling it good!)Welded a 20mm socket in the other end to make use of the 1/2 drive. 20mm gave me a good circumference to put a weld around, and some meat around the 1/2 drive.
Gonna sit on this overnight, coz I'm second guessing my math still.
Bambusiero
SILVER Star
- Thread starter
- #26
Sheesh! Now my brain hurts, trying to imagine what you are describing - and besides - I've slept since then (once or twice). I'll try and come back to this.
The torque adapter I have is similar to this one.
www.kincrome.com.au
It reads torque across the two ends.
I put the socket end in the vice, and a breaker bar on the wrench end.
I marked the breaker bar handle at 12" from the centre of the square drive.
Set it to 50#
Then I used a digital baggage scale to see how much force was needed with a 12" lever to hit the torque setting.
With a 12" lever, it took 50# of weight on the scale to hit the 50# torque setting.
So, from that, I think a 12" extension is giving me a leverage ratio of 1:1 from how the torque adapter is calibrated.
This last part ^^^ is what I'm stuck on
Digital Torque Adaptor 1/2" Drive
The Kincrome 1/2" Square Drive Digital Torque Adapter converts any standard 1/2" Square Drive ratchet into an accurate digital torque wrench. Simply set the desired torque, plug in a ratchet and socket and tighten the fastener until the digital display and audible tone indicate you’ve reached...
It reads torque across the two ends.
I put the socket end in the vice, and a breaker bar on the wrench end.
I marked the breaker bar handle at 12" from the centre of the square drive.
Set it to 50#
Then I used a digital baggage scale to see how much force was needed with a 12" lever to hit the torque setting.
With a 12" lever, it took 50# of weight on the scale to hit the 50# torque setting.
So, from that, I think a 12" extension is giving me a leverage ratio of 1:1 from how the torque adapter is calibrated.
This last part ^^^ is what I'm stuck on
Yes.The torque adapter I have is similar to this one.
View attachment 3209905
Digital Torque Adaptor 1/2" Drive
The Kincrome 1/2" Square Drive Digital Torque Adapter converts any standard 1/2" Square Drive ratchet into an accurate digital torque wrench. Simply set the desired torque, plug in a ratchet and socket and tighten the fastener until the digital display and audible tone indicate you’ve reached...
It reads torque across the two ends.
I put the socket end in the vice, and a breaker bar on the wrench end.
I marked the breaker bar handle at 12" from the centre of the square drive.
Set it to 50#
Then I used a digital baggage scale to see how much force was needed with a 12" lever to hit the torque setting.
With a 12" lever, it took 50# of weight on the scale to hit the 50# torque setting.
So, from that, I think a 12" extension is giving me a leverage ratio of 1:1 from how the torque adapter is calibrated.
This last part ^^^ is what I'm stuck on
12" from centerline to end of handle. Hang 50 lbs on it and that's 50 LB-FT of torque.
Have 24" (2 ft) of handle and hang 50 lbs on the end of it and that's 100 LB-FT of torque.
Use your dimensions in feet and lbs only and it becomes less confusing.
If your handle is three washing machines long and you hang 67 kizbits of weight from the end, that's 67x3=201 KZ-WMs of torque.
It makes more sense when you use Freedom units.
That adaptor is using a stain gage to determine load transferred through a spring bar, think torsion rod suspension.
It doesn't know or even care how long a torque arm you use because the strain gage is wrapped around the twisted axis.
What is its max setting? I can see where you could snap it off or permanently deform the torsion bar if you got rammy with it.
It doesn't know or even care how long a torque arm you use because the strain gage is wrapped around the twisted axis.
What is its max setting? I can see where you could snap it off or permanently deform the torsion bar if you got rammy with it.
Got it. Thanks
I think I mighta used metric kizbits 
So you think I'm on the right track with a 36" extension to give me 3x the torque. 50# at the torque adapter is 150# at the bolt?
Max setting is 147#.
If you have the 32 MM nut on the crankshaft bolt, and the blue bar is 36" (+/-) = 3 ft
Then, you use the torque adapter on the far end of the 3 ft blue bar.
Then use a breaker bar (or ratchet) on the TA and crank it up until you see 50 LB and that will be 150 LB at the bolt.
If your goal is 306 LB-FT at the nut, then take the TA to 102 LB-FT (138.29 Nm)
Then, you use the torque adapter on the far end of the 3 ft blue bar.
Then use a breaker bar (or ratchet) on the TA and crank it up until you see 50 LB and that will be 150 LB at the bolt.
If your goal is 306 LB-FT at the nut, then take the TA to 102 LB-FT (138.29 Nm)
I found one of these beasties at a pawn shop for cheap enough it followed me home.
250-600Ft#. Woof!
Now I just need a bulldozer to work on so I can exercise it. LOL
250-600Ft#. Woof!
Now I just need a bulldozer to work on so I can exercise it. LOL
You're overthinking it, and you're correct. Torque = force X length. If you're good with algebra you can change the length/force to meet your needs. Remember, units are your friend and you can multiply them just as you can numbers.
Ex:
First time I did this was with the engine out. I (at 150 lbs) stood at the end of a 2 foot beaker. 150 lb X 2 feet = 300 ft lbs.
Second time I walked into the local 18 wheeler shop. Told them my situation and said I could have it back in 20 minutes. They held onto my license and $200 cash, and i took home a 600 ft lb wrench. 20 minutes last we re-exchanged and I was good to go.
Ex:
First time I did this was with the engine out. I (at 150 lbs) stood at the end of a 2 foot beaker. 150 lb X 2 feet = 300 ft lbs.
Second time I walked into the local 18 wheeler shop. Told them my situation and said I could have it back in 20 minutes. They held onto my license and $200 cash, and i took home a 600 ft lb wrench. 20 minutes last we re-exchanged and I was good to go.
thanks mate
the lack of info or discussion of this type of scenario with torque adapter anywhere online had me wanting a sanity check.
still unsure of my sanity
, but think my extension bar is right
You're overthinking it, and you're correct. Torque = force X length. If you're good with algebra you can change the length/force to meet your needs. Remember, units are your friend and you can multiply them just as you can numbers.
Ex:
First time I did this was with the engine out. I (at 150 lbs) stood at the end of a 2 foot beaker. 150 lb X 2 feet = 300 ft lbs.
Second time I walked into the local 18 wheeler shop. Told them my situation and said I could have it back in 20 minutes. They held onto my license and $200 cash, and i took home a 600 ft lb wrench. 20 minutes last we re-exchanged and I was good to go.
View attachment 3210397
nice!
I don't think there's enough room for my fat ass and big feet between the radiator and engine to get my 300+ pounds on a 1ft breaker bar
Don't go confusing the commies. They don't have the means to go full Ned Kelly these days.
I think freedom units are reserved for those who fought off the British?
Could always buy the HF torque wrench, and return it when you're done for full refund but not as fun as making one on your own. I also bought a Quinn 3/4 digital torque adapter there for like $60 that I will try when I do the job again on another truck, seemed to have good reviews but I'm skeptical.
I think " reserved" is a bit of a stretch. No-one e else wants the head fúck from using them!
