[woodnthings]

let's just "assume" you can get the play out ....

... the sliders fit a snug as possible and you can still move the sled easily with no play side to side..... I have done this, so I know it's possible. No, I don't know the tolerance in decimals, just seat of the pants feel and highly trained eyeballs. :laughing:

The next issue will be setting the fence 90 degrees to the blade. This is where real accuracy is required, I did use a digital readout angle gauge, and when you make your test cuts and flip them over you get 90 degree cuts. That gauge will be your best investment.

As to negativity in a post...you post your topic and you get what you get, like it or not. Some responses will be constructive in nature others may poo poo your ideas. You must have a tough skin to post on an open forum like this, I know this for a fact after repeated cynical or sarcastic replys. Ignore those responses you don't like/agree with and you'll be much happier ... just move along.
I gave you a link to E Bay to which you responded in a negative way on another thread and I let it go. There was a solution in the link at $19.00 to which you responded "no way in hell" ...etc.
A simple "thanks, I appreciate your effort in trying" to help would have been more appropriate. :yes:

 

[woodnthings]

interesting discussion here

I have found that not all miter slots are .75" or 3/4". Some of my miter gauge bars are just a bit tighter, others loose. I have several miter gauges, older and newer Craftsman, Grizzly, Osborne, Incras .... others.

I have taken a mill file to the miter slots of my Craftsman table saw because the miter bar would hang at one point or another. A few strokes, then test, and a few more then test again and was "cured"
I suppose one could get a 3/4" steel bar and some lapping compound and work the miter slots to a fine fit. I personally would use steel for the sled bars or as I did on my sled, hardwood runners. I kept ripping strips until a got the precise fit I wanted, gave them a light sanding then attached them to the sled bottom.
There is no discernable play that I can tell.

Here's the real issue.
The miter slots and bars can be made to fit perfectly, but they are joined together by a rather large piece of plywood or MFD or other material which is subject to expansion or contraction. What may have fit and worked perfectly one month may not work as well the next month.
Another issue is the blade must be in perfect alignment to the miter slots or otherwise there will be a "heel" to the cut. It will be parallel kerf, just not a perfect kerf width.
Just sayin' :smile:

 

[woodnthings]

just thinkin' outside the "box"

Most rotating devices or assemblies are dynamically "balanced".. crankshafts etc., We use 10" blades that rotate at high RPMs and they may have some runout static or dynamic. I can measure runout with a dial indicator on my lathe at low RPMs, why not on the table saw? Then take the average between the extremes rather than one tooth which may or may not rotate "in plane".... There are some sanding plates that are advertised as table saw set up devices:

No teeth present to measure from, just a "flat plate". A dial indicator can now ride the extremity of the plate and give the "combined" run out of the plate and arbor. We are really splitting hairs here but for those who feel it necessary it should work fine.

I do use one to set my RAS blade square to the fence. :yes:

 

[woodnthings]

is your square "square"?

There are several means to make a square line or measure a square cut. Use a framing square. Use a T square either drafting or drywall. I use a digital protractor if it has to be exact.

Measure or register off one edge. Scribe your mark using the framing square. flip it over make a mark "parallel" to the first one. Is it parallel? Out at the end it will show the greatest deviation. Once you have square, it then it becomes the "master for checking 90 degrees. There is a way to peen the corner of a square to get it right on. http://zo-d.com/stuff/how-do-i/how-to-check-and-adjust-a-framing-square.html

I wouldn't bother chasing a piece of panel around the miter gauge or sled 4 times. It's either square or not. What if it's not square, now what? How much error so you adjust for ... ? Were all the pieces registered exactly the same...:blink:

You can measure the diagonals, but the result will only be as good as your registration, your measuring tool and as good as your eyeballs can read it.... usually good enough for woodworking. You got to get a collection of measuring and checking tools you trust, then move on to the making part of the project. If you are always questioning your measuring process, you will not only NOT enjoy it, you won't get anything finished.

 

[woodnthings]

I don't understand a few things...

The screw you show has an oval head and is not meant for a countersunk hole as you show in the bar. :blink:
Why not use the bar and the holes there in as the drill jig when locating the pilot holes going into the sled?

I would not alter the bar in any way, just use the proper flat head screws to attach the bar to the sled. :no:

Unless I am completely missing your issue... :boat:

 

[woodnthings]

Ok I get it

Drill the sled for 3 holes, 1 on each end and 1 in the center. Put the screws to it to hold it in place then drill the rest of the holes. You can use a bit that's the same diameter as the bar hole to center your pilot drill. Just drill in a slight amount to create a center. :yes:

 

[woodnthings]

exactly

Do this:

I'd put the bars in the slots over a 1/8th or less shim laying in the slots.

I'd get the bars perfectly centered, then lay the sled base over them and get it positioned where I wanted it.

I'd slide the rip fence to where it was just touching the edge of the sled base, lock the rip fence, then remove the sled base.

Add poster tape to the bars, then using the rip fence as a guide, lower the sled base onto the bars.

I could then lift the sled up with the bars attached and remaining perfectly aligned so I could flip it over and attach permanent screws/bolts.

Then this:

Drill the sled for 3 holes, 1 on each end and 1 in the center. Put the screws to it to hold it in place then drill the rest of the holes. You can use a bit that's the same diameter as the bar hole to center your pilot drill. Just drill in a slight amount to create a center. :yes:

This should help avoid any shifting in the bars as you add the remaining screws. :yes:

 

[woodnthings]

modifying ...

I think you are letting the tail wag the dog here. There is no guarantee that the drill you show will self center in the existing hole, rather it probably won't. Wood should be the subject material not the metal. If care is taken to pre-drill the holes into the wood using the bar as the guide, the holes should be aligned properly, and the flat head screws will keep if from shifting afterward.
Feel "free" to do what ever you want, but that's my "free" advice.

I don't know why y'all have such an aversion to modifying metal things. If there were flat, recessed areas on the bars, I wouldn't have to mess with anything else.

I've modified more metal things than you would ever believe. Cut, welded, machined, drilled, countersunk, bent and re-bent... etc. I have a 13" metal lathe, 2 metal cutting bandsaws, 3 sheet metal brakes, a 3 ways to weld metal except TIG. I've drill enough holes in metal to sink a large ship including custom truck bodies, mobile bases for stationary power tools and buidling a 990 lb road scarifier for my tractor. Here's winch mount I just built: