Calibrating TS-Aligner Jr.
I receive a number of inquiries from people having trouble calibrating their TS-Aligner Jr. The manual and video contain detailed instructions for this. This page should help to address some of the problems that can hinder you from obtaining accurate results. None of this material is new. All the photos come from the video or the manual.
A word of advice...
Every single Jr. I ship is very carefully calibrated at the factory. We have a lot of experience doing this and are very careful to make sure that the process is done correctly. After having done literally thousands of calibrations, I think that we can manage to do a pretty decent job. However, some people just don't trust factory adjustments and feel that they can do it better on their very first try without following directions. Please try not to be one of these people. If the temptation overwhelms you and you discover that the factory calibration on your Jr. has become hopelessly screwed up, don't despair (and, please don't call or send me email to say that your Jr. is defective or arrived un-calibrated). Simply send it to me with a check for $10 + return shipping and we'll restore calibration for you and return it without a word.
Before you start, make sure you understand how the Angle Attachment Gage works. The article will give you some insight into the process that you need in order to understand what is happening during the calibration process. If you have trouble with the concepts presented, then do not attempt to calibrate your Jr.
First things First
Make sure you have the following tools:
An accurate 45 degree precision ground hardened steel angle block. Don't attempt to calibrate a Jr. with a plastic drafting triangle or a speed square. If it isn't a precision ground steel machinists angle block, then it's not likely to be accurate enough.
A known flat surface. We use a 4" thick granite surface plate. The top of most good table saws is adequate but don't just assume it's flat. Many people who have reported problems calibrating their Jr. have discovered that their saw top isn't really flat. Use a quality steel straight edge to check it.
A good quality "T" handle hex wrench. We use LocTite to secure the calibration screw so that it will stay in place once accurate calibration is achieved. You'll need a pretty stout wrench to break this bond and make fine adjustments. The wrench we supply with your Jr. can be used but may not work very well.
If you don't start with these basics, then you'll encounter considerable frustration and wasted time. If you insist on ignoring these three items, then please don't compound the situation by calling or emailing me. You're liable to get me pretty frustrated too.
The Setup
Make sure your calibration surface is clean. If there is dust or dirt under the cross bar or the angle block then you won't obtain consistent results.
Detach the cross bar from the base. If the cross bar isn't sitting flat on the calibration surface (because it was locked to the base at an angle before being put down) then your results will be inaccurate.
The cross bar and angle block need to be "in-line" with each other. See the photos below, which shows how a straight edge is used in this setup.
I've clamped a large square to the table top because it's easy to arrange and provides a good straight edge. Certainly, any good straight edge can be used so long as it keeps the angle block and cross bar in-line with each other.
Both the cross bar and the angle block are placed against the straight edge during calibration. This keeps them "in-line" with each other. If the dial indicator points don't line up with the edge of the angle block, then you'll have to use a spacer. Generally, you'll need to put a 1/4" spacer between the cross bar and the straight edge. You can use anything that won't shed dust or cause other problems. A 1/4" drill bit is fine.
The dial indicator must rest properly on the top of the set screw. This is done by holding the cross bar upside down, pushing lightly on the bottom of the Angle Attachment Gage, and tightening the screw that holds the dial indicator to the cross bar. This technique is demonstrated in the following photo:
Pushing down on the indicator from the top is the WRONG method and will not give you good results. Many people ignore this detail and send us their complaints about calibration accuracy. This really is important.
The indicator must be mounted on the correct side of the cross bar. Not many people get this wrong but some do. Notice from the photo above, the loop on the indicator is opposite the slotted side of the cross bar. The indicator mounting screw goes through the loop, through the hole in the cross bar, and into the nut in the ""T" slot.
Make sure your setup conforms to what I've laid out here. If you decide to ignore one or more of these setup details then I wish you the best of luck because I won't be able to help you.
The Process
First and foremost: the "Approximate" calibration method which is outlined in the manual and demonstrated on the video is only approximate. It will only get you close. It does not provide a good indication of accurate calibration. Quite often, the front of the Angle Attachment Gage will not be perfectly square with the calibration surface when proper calibration is achieved. So, don't conclude that your calibration is wrong just because it doesn't agree with the Approximate calibration method.
"One Inch Point": when the dial indicator plunger is pushed in exactly one inch (almost all the way). This happens when you measure a square surface:
"Zero Point": when the dial indicator plunger is pushed in just a little bit, enough to bring it to zero. This happens when you measure a 45 degree surface:
The One Inch Point is set by sliding the Angle Attachment Gage (AAG) along the dial indicator stem. Slide the AAG toward the indicator to increase the reading. Slide it away from the indicator to decrease the reading. Don't let the AAG get so close to the indicator that the lower point no longer touches. Both points must be in contact with the surface.
The Zero Point is adjusted by changing the tilt of the dial indicator. To do this, loosen the indicator mounting screw and adjust the calibration set screw. Turning the screw clockwise will increase the reading on the indicator. Turning it counter-clockwise will decrease the reading.
Never adjust the One Inch Point by changing the dial indicator tilt. Never adjust the Zero Point by shifting the position of the Angle Attachment Gage.
During the entire calibration process, you need to keep the SIDE of the Angle Attachment Gage square with the calibration surface. You can do this by pushing it against the 90 degree side of the angle block as shown below:
The process must be done in proper sequence. Do not do things backwards or out of order. This is the proper sequence:
Set the One Inch Point using the 90 degree side of the angle block.
Check the Zero Point using the 45 degree side of the angle block.
If the Zero point is not correct, adjust the dial indicator tilt and repeat step 1 followed by step 2.
If the Zero point is correct, do not adjust the tilt of the dial indicator. You are done.
You SET the One Inch Point, CHECK the Zero Point, and (if necessary) ADJUST the indicator tilt. You don't re-check the Zero Point until after you re-set the One Inch Point. Tilting the dial indicator will change the both the One Inch and the Zero Points. You only want to check the Zero Point when the One Inch Point is properly set. The two measurements will converge so that they are both correct at the same time when you have the correct dial indicator tilt.
A final word
It's pretty darn easy to set the One Inch Point. The trouble with this whole process is getting the dial indicator tilt correct. With a little practice it's not too difficult. But, if you use angle blocks to measure angles, then you don't need to worry about precise setting of the indicator tilt. You only need to set the One Inch Point with an accurate square.
Last revised: March 11, 2007.
