Four Inch Digital Protractor from the Craftsman Gallery
For years I have set up my table saws, band saws and fences with a combination of try squares and engineering squares. Their accuracy has to be accepted even when I am a little suspicious. I can test one against another or against an engineering square which is ' guaranteed' to be accurate. The biggest problem is actually measuring angles.
I have drawn them out on the computer or struggled with geometry protractors and adjustable fences but none of them have been entirely satisfactory so when Lewis of the Craftsman Gallery offered me one of their 4 inch Digital Protractors to test I jumped at the chance.
This protractor comes in a neat case with belt clip and measures 0-360 degrees. Accuracy is stated to be within 0.1 of a degree and it has a clear LCD display. The pivot point has an adjustable tension knob that is easy to grip.
Built into each edge are high strength magnets which are very helpful when adjusting saw blades etc. Contrary to my first thoughts the small size is a distinct advantage when setting up saw blade angles as the edges do not get fouled by the blade carbide tips.
A neighbour is a high precision test engineer and checked it out in his lab. This model with a new battery proved to be better than expected. Not always consistent with the readout but varied from either spot on at 90 degrees or to within 0.04 degrees. better than advertised and good enough for me. The prime guide to accurate readings is ensuring that it is correctly zeroed. Either open it up or fold it it up and place on a flat surface such as a window pane or saw table and press the zero button.
|Only three buttons but four functions. Obviously on/off but I am
pleased that it does auto shut-off to save the ubiquitous CR2032 lithium
The zero button to well......set the zero point.
If you are seeing something like this you can only read it in Australia! Press and hold the DIR button and the display will flip the correct way up.
A quick press of the Hold button will lock the display
|I pulled out some old squares to check. These are junk sales rescues hence the marked faces but the edges are fine.|
|This really old rose wood and steel square proved to be still spot on after, I suppose, a century of use. They don't make 'em like that now!|
|I thought this adjustable Jack of all trades would be miles out but it proved to be not too bad at 90.1 degrees inside and out.|
|The 45 degree angle was not up to scratch though.|
|Here is my trusted engineer's square showing 0.5 degrees error.
DO NOT DO THIS.
I earned a slap on the wrist from my neighbour!
Do not measure inside edges against outside ones.
The inside edges were precisely 90 degrees as were the outside ones. The blade is not exactly parallel but it is not rated for that.
£ 50.00 plus for for one that is.
|For maximum usability pair it up with a quality sliding bevel.
Either set the slider from the work and measure the angle or set the DP
and set the bevel to it. Makes it easier to access those difficult
This is where I encountered a slight frustration. Setting the Digital Protractor to a desired angle is not too difficult if you tension the pivot knob but it can't be locked solid and if bumped will move. Only a fraction of a degree but it can be annoying.
This gauge is brilliant at measuring angles but in some circumstances not so good for setting things at an angle.
I am being critical here and the answer in those circumstances is to set the DP then set a sliding bevel to it. Lock the sliding bevel and use that to set the work.
|Setting up the blade on my home made Table Saw.|
|Adjusting the Band Saw table is a piece of cake.|
No parallax problems now when setting this one up.
Compound angle cutting on the saw should be much more accurate now.
|To test your dovetail bit cut first cut a socket and then measure that with your sliding bevel and lock it with the thumb screw.|
Now measure it with the Digital Protractor. An 8 degree bit was used.
The DP reads 97.85 degrees here.
97.85-90 = 7.85 degrees.
Good to know when setting the scales on your 'Rat/RB!
If for example setting a blade angle on a table saw do not set the knob tension high. Zero the DP and then place it on the cast iron table and against the blade. The magnets will hold it place. Now adjust the saw blade whilst watching the display until the desired angle is reached. If you set and tension on the DP first the magnets can pull the DP open to the incorrect angle.
The uses on the Router Boss are numerous but this Digital Protractor is perfect for checking your dovetail bit angle. Cut a test socket and measure the angled sides of the cut. Do it and discover how much variance you can find from the stated angle!
I lent this little DP to a friend who runs a joinery business www.comptonjoinery.co.uk and they were enthralled by it. The small size is ideal for setting up machinery and ensuring cut angles match up. Only very minor criticism is that it can't be firmly locked.
I have to say that after all these years I finally have a solution to all those angle measuring jobs and am really pleased with it. It has a quality 'feel' and somehow is rather tactile. The small size is an advantage and is useful for all workshop jobs not just on the Router Boss.
Compton Joinery recommend it as do I.
Good as a reference to check my other tools
Can't reliably lock at a set angle.
4" Digital Protractor from the Craftsman Gallery item 35-604 Price $34.00
"Versatile electronic digital protractor with LCD display precisely measures outside and inside angles from 0 to 360°with 0.1° resolution. Magnets on edges of folding arms grip metal objects such as fences, saw blades and miter gauges. Use to measure cabinet joints and wall corners or to set miter and bevel angles on machines. Compact 4" arms. Includes extra battery and case".