Ron,
If you don't mind, give us some feed back to all you discover about it.. My hearing eyes are wanting to know!
The protective case that it comes in seems to be well thought out and should keep it reasonably well protected. It has a hard "flip-up" cover over the keys/display that is easy to manage and has a "Quick Reference Guide" on the inside for spindle speed, feed rate, and thread sizing.
The handbook is like most technical handbooks, a little daunting at first. That is, at least until you try out the few examples given and familiarize yourself with how it functions.
You can set the unit up to use either standard or metric units, set the number of decimal places/precision, as well as give answers in fractions (if you're a bit masochistic
) ie. 1/64, 1/16, etc.
After getting used to it a bit it is fairly simple to calculate the spindle speed, feed rate, and chip load. For example:
To calculate the spindle speed needed for a 3/4" endmill with a cutting speed of 300 sfm (surface feet per minute) you simply press "3" then the "/" followed by "4" and the "Diam" button to set the diameter of the end mill (or work piece in the lathe). Next you enter the cut speed by pressing "3", "0", "0" and the "Cut Speed" button. Now that the parameters are in you simply press the "RPM" button and it will show "1528".
It's pretty much the same for feed rates and cutting speeds. The chip load calculation is just as simple: Input the cutting speed, say 0.024"/rev and press the "Cut Feed" button and then enter the number of "teeth" on the endmill, say "4", and hit the "#Teeth" button. Finally press the "Feed/tooth" (feed per tooth or "chip load") and out pops "FPT 0.0060 INCH"
The one thing I think is lacking is that it would be nice to have a "table" of suggested cutting speeds for different metals in the calculator itself. It's simple enough to consult another reference or if you are used to working with a particular metal you probably already know what it should be but I still think it would be nice to include that information.
Speaking of references, the "drill size", and "threading" functions are great. You can put in the size of hole you want to make and press the "Drill size" key and it will give you the number, letter, or fractional/decimal size bit closest to the size you need. If there is not an exact match it gives the next size smaller. No more trying to read the tiny printing on my drill chart that came with my bit set.
In the threading reference you just input "1/4" hit "thread size" then put in "24" and press "thread size" again for 1/4" - 24. Pressing "thread size" repeatedly will go down through a list of values for "cut tap drill size", "roll tap drill size", "close fit drill size", "free fit drill size", "Min. internal pitch dia.", "Max internal pitch dia.", etc. etc. The information given is dependent on whether you set the "Thread class" to internal (1B, 2B, 3B) or external (1A, 2A, 3A). If you're doing it in metric all the thread tolerance classes are included for those as well. It can also give you the wire sizes for "Ideal, Maximum, and Minimum wire sizes" for measuring a particular size and thread. It seems like it will save a lot of time not having to grab your "Machinist's Handbook" and look it all up in the charts.
Another slick little function is the calculation of bolt patterns. You can lay out a circular pattern by inputting the bolt circle diameter and the number of bolts and it will produce a list of "X-Y" coordinates as well as center-to-center spacing based upon where you set the start coordinates, and the angular position of the first bolt (those are optional settings). Your DRO may already have this function built in but if not this could be a great little headache saving device.
It is set up for making both right triangle functions and circle calculations more intuitive with dedicated keys. Trig. functions are also included for where they can come in handy.
To save on batteries there is an auto-shutoff for those of us who might get "distracted" while performing other operations, that's always nice. It also has a 1-year warranty.
Overall I'd say that it was a great buy (if you buy it before the end of December from Littlemachineshop.com there is a $20 dollar rebate) at $55 + shipping (rebate is probably good where ever you buy it but I like doing business with the "small guys" - see my note about quick service above
).
I can try and answer any other questions you might have if anyone is interested.
-Ron
