[ryan50hrl]

Keep in mind..... .0015 can make a difference in metal working.......working in woodworking to 1/650 the of an inch is pretty unrealistic. I'd not worry about that. I'm usually pretty happy if things are within 1/64th. Wood expands and shrinks....whats perfect today won't be tomorrow.

 

[ryan50hrl]

The problem I see is how are you going to ensure perfectly straight slots? If you double 1/640th your at 1/320 th. again, I don't know a whole lot of guys working in wood to those tolerances.

 

[ryan50hrl]

Have you watched this video? http://youtu.be/UbG-n--LFgQ?t=21m

I have.....and if you can find anyone else on this site that works to within 1/640th ill walk away...

But your imperfect incra bars are yet another example of woodworking being a different standard than metalworking.

It's just not realistic. .....I enjoy perfection as well.....but I think your chasing a pipe dream.

 

[ryan50hrl]

I wish I knew how to better put into words how frustrating it is to expect help and get negativity. I appreciate your desire to tell me that your personal goals for accuracy are lower than mine. I'll will even admit that you two are probably(definitely) better craftsmen than I currently am. However, if you or anyone else would do me the courtesy of refraining from commenting on this thread unless you have some suggestion that you think may improve my miter slots, I would greatly appreciate it.

I'm not trying to be negative....I'm trying to keep you from making it worse. If you really want them to be perfect, take the top off, take it to a machine shop with a mill and have them repair it. There's no way (worked in a machine shop for a few years) that I'm aware of to make something accurate in cast iron to the tolerances your looking for BY HAND!!!!

 

[ryan50hrl]

No negativity here.....but you might not like what I'm gonna say?

We ROUTINELY work wood to .0015....and infact a lot of shops do.Heck,take a look at any decent shaper or moulding machine,widebelt sander,etc.etc.

.0015 is one third the thickness of a piece of paper....or roughly the thickness of an average human hair...

I don't know of any machines that have adjustments that fine. Certainly none that I've ever used in woodworking. The large wide belt sander I take my stuff to has a readout of .005 or a factor of 3 times smaller than we are talking about.


All I'm trying to say....is that chasing perfection in accuracy is futile as wood expands and contracts rapidly with climate changes. And .0015 seems excessive.....

Just my humble opinion that using a handheld piece of sandpaper will do more harm than good in trying to remedy the situation. And once the material is gone you can't add it back.

 

[ryan50hrl]

Fair enough....it's your saw, and your projects. Good luck.

 

[ryan50hrl]

I felt like the force required to move the caliper open and closed was enough to deflect the blade a tiny bit. If the lug-back indicators are typically smoother, I'll buy one immediately.

Yes they are

 

[ryan50hrl]

The sanding discs don't work very well as tablesaws spin to fast for sanding. You'll burn/gum up the discs really fast.

 

[ryan50hrl]

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:

I agree, but I think he's saying he can't drill them precise enough?

 

[ryan50hrl]

It's not that we have an aversion to modifying metal things that need modifying....it's that we tend to use things in the way they were intended to be used. There are thousands of guys that have bought these bars and use them with the tapered holes....and they work great. I think most of us are just against extra work for the sake of extra work.

 

[ryan50hrl]

I hear ya. But I checked out the reviews on amazon for these miter bars and the first review was expressing my same concern for the coutersink holes. The one comment in response was to the effect that the double stick tape would keep the bars from moving, and ten out of ten people found that comment useful. I must be the only one who's dealt with adhesive in the heat. It likes to get gooey and slide around. I don't have an air conditioned shop. If the doors are closed and the fan's off, I have no idea how freakin hot it must get in there. I just know as much as I've gone through, I'm not going to rely on tape.

And, my miter slots in the table saw certainly weren't intended to be tight in the front and back. Modification was the only remedy, there, if I wanted to take full advantage of adjustable miter bars.

In no way did I mean to imply anyone here wasn't competent with metal. I was sure you were, which is why I asked about it. Does that make sense?

The sticky tape is to hold the bar while you drill and fasten with screws. I've used that trick before.