Ed@Demonspeed

Would be interesting to know. And good to know about the snap on. I am currently in the market for a new torque wrench.

Thanks

Ed

guardsredcab

Still trying to get to the bottom of this issue between Snap-On and Precision. Spoke to a "technical specialist" at Precision last week. She didn't know the answer but was supposed to email me literature that would. Haven't received anything yet. I can't cite it off the top of my head, but recall reading on the Snap-On web site that, although less accurate in CCW than CW, it would still work CCW. I also called PMNA parts, thinking they actually supplied a wrench with new cups...apparently not. They suggested Snap-On. I'll post more as I learn more.

Thales

Not sure what this is all about - I have the 3/4" Precision C4D600F and the head can be mounted CW and CCW on the main shaft (it just has 2 quick release holes, one on each side...). Certainly NO reason why accuracy would be any different in either direction...

rebrewer

There IS a reason accuracy is different. I just don't know what it is. Here's a bit from one of the 3/4" electronic wrenches "• Torque Accuracy: +/- 2% CW and +/- 3% CCW, 20–100% of full scale". It's common for accuracy to vary with rotation direction but I don't know what about the design creates this. 3% is plenty accurate for wheel nuts, anyway. There are other factors that will affect the reading more than that.

I should clarify that the model I have, not all models, is CW only.

rebrewer

So it appears that only the split beam style (the ones you don't have to zero) are limited to CW measurement:

• A unique split-beam measuring element provides the accuracy and eliminates the heavy coil spring used in conventional click-type wrenches, which makes for fewer moving parts, reducing friction and wear to a minimum

• Designed for measuring torque in a clockwise direction only – wrench is not reversible

So if you need CW/CCW functionality go with the coil spring style that has to be zero'd when you are done, or electronic, which doesn't, but is overkill for wheel nuts. My Snap-on guy is down for a group buy if anyone is interested. PM me if so.

Thales

Snap On TQR600E looks to be the same design as the Precision based on pictures. Are you certain there isn't a hole on both sides of the main shaft? Seems silly that Snap On wouldn't put a second hole to allow CCW...

It is literally the same mechanism in both directions - only diff is if the head points to the left or the right when you look down the shaft.

EDIT:
It's possible the TQR600E head is CW only. Not sure why. However, My C4D600F definitely does both CW and CCW.

rebrewer

Kevin, I agree it would seem silly not to put a second hole in especially if it creates a limitation not to. That said, there must be a design limitation that causes them to do this. I'll either disassemble mine or call the guys who calibrate them.

Thales

...

Viperbob1

That is incorrect. The split beams I use from Precision do both CW and CCW.

This is a nice Snap On. Also over $1000 https://store.snapon.com/Standard-Mo...--P642512.aspx

rebrewer

I'm referring specifically to Snap-on branded wrenches, so it is correct. I don't have a relationship with Precision and can't speak to their functionality.

guardsredcab

Here's what I was referring to from the Snap-On website regarding their model QD4R600A
Description
• Torque: 120–600 ft-lb
• Virtually maintenance-free sealed ratchet heads keep out dirt and moisture
• Cannot be accidentally disassembled if wound down past scale
• Accurate readings to ±4% CW and ±6% CCW from 20% of full scale to full scale

Bob, Is the Precision unit you use the C5D600F (a 1" drive)?

rebrewer

Hi Greg,

No, to be clear, I'm using the Snap-on TQR600, which is the series that is not rated for CCW use. Viperbob1 and I are questioning why what looks to be a similar Precision wrench does CCW. Snap-on owns CDI but I don't think they own Precision. https://www.snapon.com/EN/Our-Company/Our-Brands

Precision had a patent for the split-beam design that allowed accuracy in both directions so perhaps that it why the similar design Snap-on is unidirectional. That patent may have run out by now - I don't know.

Most of the other Snap-on wrenches are bi-directional. I'm using 3/4" drive.

Bob

Viperbob1

Oh sorry....

rebrewer

No worries, it doesn't make sense to me either that the Snap-on TQR series won't do CCW. Maybe it's the patent thing.

guardsredcab

Sorry Bob (@rebrewer), I meant to address the question to Viperbob. He said he uses a Precision Instruments wrench both CW and CCW.