CDI Micro Adjustable Torque Screwdriver, 1/4 Inch Hex Drive, Range 5-40 In Lbs (401SM)

This CDI micro torque screwdriver is a product distributed through (besides Amazon) Snap-On. This is one of those tools that I don't use that often, but when its needed it is Really needed. Before I bought this item a little over a year ago I did quite a bit of on-line research and discovered that this CDI tool was literally the "only game in town" in terms of accuracy and reliability. The only other contender that even came close (but not very close) was a torque screwdriver sold by Brownells. Since I do not have a calibration lab I went by the accounts of multiple on line sources, and would suggest that you might do the same...things might have changed in the past year. Amazon had the best IN STOCK price I was able to find a year ago. I do my own gunsmithing and use this tool whenever a precise amount of torque is required per a manufacturers specifications. The torque settings are easy to see and adjust within one inch pound increments. The tool accepts regular screwdriver type bits, and therefore will accept just about anything used to tighten small machine parts. So whether you are tightening a screw or a nut (or something in between), and you have the bit to fit your application, this will do the job for you. The build quality on the tool is excellent. It has the heft of a solid little machine and the handle affords a positive grip that lets you apply the downward pressure necessary to keep your bit solidly on the screw and thus avoid any slippage that could mar your workpiece. As far as I can tell (without a calibration lab) this tool gives the proper, repeatable result. I have not stripped a screw or experienced a malfunction of any sort connected with the use of this item. I am very picky when it comes to tools and machines...I earned a living most of my life as a clockmaker specializing in the restoration of antique clocks. These days it is difficult/impossible to acquire high quality tools at a reasonable price. This CDI torque screwdriver is a rare exception in a world of shoddy tools that simply don't measure up to any standard of quality. I believe the reviewer that downgraded this $100+ tool should look toward the Much More Costly torque devices that are intended for 24/7 usage. Under "normal" use I would expect this tool to last the craftsman a lifetime. Kudos to Amazon for making this reliable, high quality tool available to the workman at a good price.

When considering this tool to purchase - it should be noted that when you are using a tool 24 hours on all shifts (sounds like 24x7) - you also are probably using it more than just once each hour. Once each hour would result in a 5,000 use cycle occurring every 208 days. However, in a busy industrial environment - using this tool just twice each hour - results in 5000 cycles every 104 days. Essentially - every 90 days. You also have the fact that using any torque wrench in the upper or lower ends - decreases the life of said wrench. All of this information is readily available from CDI. The following are quotes from them as to the care of their tools and torque wrenches in general: "To determine which torque wrench capacity is best suited for an application, many factors must be considered. However, as a recommendation, use a torque wrench in the middle 50% of the overall capacity of the tool. This will result in longer tool life, ease of use for the operator and increased accuracy from "clicker" type torque wrenches Torque wrenches should be "exercised" a minimum of three times at 100% of full scale before use Torque wrenches will last longer if reasonable care is taken. Always unwind handle to the lowest setting after each use. Do not attempt to lubricate the internal torque mechanism. Clean torque wrench by wiping, do not immerse. The wrench should be sent to a qualified calibration lab once every year or every 5000 cycles for re-calibration" The instructions for this specific micro adjustable torque screwdriver (401sm) - state to have it calibrated and gone through every 5,000 cycles - or one year - whichever comes first. ALL torque wrenches have useful life cycles. CDI is at least being honest - and putting in print - the life cycle and service requirements. If you use this tool only 3 times each hour - at various settings - you should have it serviced every 69 days minimum. This is just part of the cost of doing business and quality work. I have owned this tool for quite a number of years (just purchasing another one); and find it extremely adequate for small screws, and misc. fasteners without a lot of mass - which require a torque value; etc. With a very long life span. Easy to grip, very visible (bright blue), and easy to use. An excellent tool with excellent cditorque com support.

2nd Update: Jan 30, 2013 So far 2 of the 3 units purchased are working well. I had the 2 checked in my calibration lab and neither tool had a problem. I also recently purchased a 4th to replace the one that failed. I brought the review up to 4 stars because I still think this is a good product. My operators all love this tool and now prefer it over their previous driver. Currently the 3 drivers are only being used by one or two operators so they don't have the same use as the first that failed. Update: August 27, 2012 Sadly, I had to decrease my rating from 5 stars to 3. It is still a good tool and my operators love it but if they only last 6 months it isn't worth it. I sent the first unit back to my calibration lab for a 6 month overhaul and the results were disappointing. They were not able to get the tool back into calibration. The low end was a little off, around 1 in lb below the setting. The upper limit was worse, around 48 in lbs when set to 40. I had this particular tool being used 24 hours a day on all my shifts to check for this exact problem. The life span may be a little longer depending on your usage. The highest torque we have is around 36 in lbs. After 3 months of use with the first article, and my calbration labs approval, I purchased two more that are currently being used in production. They have been in use for 2 months with no problems. Once those have gone through my calibration department for their 6 month overhaul, I will update this review. (Original Review March 2012) I purchased this torque driver to test along with others before getting sets for all my operators. So far I have been extremely pleased with the price, performance, and the feedback of my employees. We are using it on multiple torque specs between 10 and 36 in-lbs. My calibration lab was very happy with the tool; both the low and high only had a 2% variation which is very low when compared with our other drivers. My seasoned operators (who usually do not like change) were very pleased with this design and how easy it is to adjust. I am now putting it through the test and having this one used through all our shifts checking longevity. Afterwards I will send it back through calibration and to double check variation and show there are no problems with adjusting torques. If I run into any problems I will update this review.

I bought this to mount a rifle scope onto my AR15. From extensive researches, I narrowed down my selection to this CDI 401SM (it's basically a Snap-on tool) and the Wiha TorqueVario-S screwdrivers. Both got very good reviews, but the Wiha is $10 cheaper. I ended up choosing this CDI screwdrivers due to the fact that it's made in the USA, more compact looking, and the best of all is that I don't need a second tool to adjust the torque whereas with the Wiha you need a SEPARATE wand that you have to insert into the main screwdriver and crank it to the desired torque level. All I have to do with this CDI tool is to pull the adjustment cap on the bottom out and rotate it to the desired torque level. I just don't want to kick myself in the head for losing that second-piece adjustment tool or run around looking for it everytimes I need to adjust the torque on the Wiha. Plus, the Wiha includes an extension that does NOT house 1/4" bits. In order for it to accept the normally used (in the USA) 1/4" bits , you have to chip out another $12 for the right size extension. So....it's pretty much a no brainer for me to pick this CDI Torque screwdriver for the reasons above. The product arrived well packaged with a calibration certificate. The screwdriver itself looks beautiful, high-quality, strong, and fits my hand nicely. Also, the indicating window is clear and easy to read. I'm completely satisfied with this purchase and feel more confident whenever I work on my RC helicopters or mounting an expensive scope (I mean REALLY expensive) on my rifle. Thanks to Amazon and Snap-on!

I bought this torque driver to do work on my guns. In this job precision is a must. The driver comes with a calibration chart to show its accuracy. It is very easy to adjust from one torque setting to the next and has a very audible click when proper torque is reached. It has a metal body so there's a good weight to it in your hand and it has an easy to read window and bar line for the scale. This tool is made for Snap-On, and anybody that knows tools knows that Snap-On is some of the best with very high standard requirements even for their contracted tools. I would recommend this tool to my friends anytime.

Works very well. Intuitive process to set the desired torque. Includes a small case to protect it.

Great product!!!!

I don’t know whether this is good or not but the make/model is actually a Williams 401SMW. I hope it does what I need it do