Shopsmith Forums

Yup, the reviews were interesting and informative. I think I am back to the drawing board.

The adjustment screw should have a thread pitch of 32 tpi so that a half turn is 1/64" and quarter turn is 1/128" etc. I am thinking you need to clamp it to the front fence rail. Polish the part that contacts the fence so it doesn't scratch the fence.

You may have to play at using it to get the touch down so the fence doesn't shift when you clamp it, maybe having the front lock partially engaged so the fence just barely slides.

I think you can make this work.

Now that you have indicated you are thinking about miter slots, here is a jig (plans available) that is micro adjustable and it sets into miter slots. Yes, it is not for fence adjustments, but there is no reason why it couldn't be! If you made one of these that fit into only one miter slot it could be made to adjust the fence on the other side of the blade.
http://www.shopnotes.com/plans/box-join ... ce-system/
If you want to hang onto the auxillary table idea, the two miter bars could be made to straddle the table.
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Although, I'm not particularly interested in having a micro adjustable fence, I still think attaching the jig to the table rails would be a better idea. Instead of "aluminum magnets", it would be easy to have a couple of thumb screws to snug it to the fence.

Another quick thought- If you could attach a strip of sheet metal onto your fence's base assembly - then you could push/pull.

reible wrote:...Ed in Tampa:

Make sure you check out the videos at Incra, live demos, TS-LS table saw fence and I think it might be in part 2 but it wouldn't hurt to view all three. The micro-adjuster I think is in part 3 but again I would think you will want to watch all three parts. If it is still unclear I'll see what I can do to give you more details then you ever wanted to know about how it is done on the Jointech system....

Ed

Reible
I have watched all the video on the incra site. One thing I really don't understand is how to you align the fence to the blade in the first place?
Once you do that alignment, let us say your able to make it within .001" of perfect how do you ever go back to the same adjustment again. I would think you may hit dead on or .001" the other direction the next time which has the potential of putting your two setups as much as .002" difference.

If that is possible what is the point of worring about .001" fine adjustment since there could be a double that error already?

I evidently don't understand something somewhere.

I have one of the very early model Incra fences (Incra Pro Jig). It does not have all the bells and whistles (MicroAdjustability) but it is accurate to 1/32". The amazing thing, it is capable of absolute repeatability Repeatability, I believe, is Incra's claim to fame.

The accuracy comes from the interlocking (opposing) teeth that mesh to position the fence. Move one tooth and you have moved 1/32". Move two teeth and ....

Move three teeth when you wanted to move two and you have a 1/32" error.

Thankfully, this thing allows for human error. Building something that would not allow you to make a mistake would take all of the fun out of it. I think they call that computer guided manufacturing. Absolute perfection but no skill (except for the guy who wrote the software).

Hey Ed,

I did a rather lengthy post in the review area to answer some of your questions and a couple of others that have ask other related questions.

The key here is how close you can get to zero. Since the tool can step in .001 steps the scale lets you guess half that amount or .0005. However as in all things wood we know that wood moves and that fibers compress and expand after being worked... you set the planer up to give you a half inch and measure it and say wow I have this cut right on .500 and a few minutes later it reads .503 It doesn't mean the tool can't be set right, it doesn't means the materials we work with are not going move on us.

So the claim on these tools are that they can be taken down then set back up a week later and you can do it within .001". The answer is you should have no problem doing that machine wise. (However different conditions and other factors may make the resulting cuts different even if you had not moved the anything for that week). What you can do is make test cuts and get the results of these and reset the system within the .001" of what you had the week before... ie if you cut a piece 2.000" you can go back and have it cut 2.000" this week but hidden way in the next decimal place one might be 2.0009 and the other 1.9999 which will both read 2" with a true difference of .001". So are you now really confused???

Ed

Ed in Tampa wrote:Reible
I have watched all the video on the incra site. One thing I really don't understand is how to you align the fence to the blade in the first place?
Once you do that alignment, let us say your able to make it within .001" of perfect how do you ever go back to the same adjustment again. I would think you may hit dead on or .001" the other direction the next time which has the potential of putting your two setups as much as .002" difference.

If that is possible what is the point of worring about .001" fine adjustment since there could be a double that error already?

I evidently don't understand something somewhere.

I now have the Incra LS system on my free standing router router table and the Incra TSIII for the Shopsmith 520. (Two very similar units except for size.) On both I neeed to use some really thin shims which were provided by Incra, in order to square the fence. Personally I view square to the blade on the saw as more important than on the router table. The shims work beautifully. I was surprised at how easily they correct squarness. As long as the squarness of my blade doesn't change and I don't remove/reinstall the incra set up from the 520 I have never noticed any change. I will confess to having used the TSIII very little. I am really interested to see how Dusty does with his quest. fjimp

Number 16 is an Excellent post! Thanks Ed!

Here's a soapbox I thought applicable to this thread: It is referring to the use of real wood cut from a tree, not referring to man made wood, or wood substitute products.

I have always been surprised of how many of us forget about the physical make up of the substance we prefer to work with. So often it is thought of as a solid substance with no coefficients of expansion and contraction. However it is a substance that is made up of cells, lumens and spaces between cells, all that will always adsorb and desorb water.

I've always been taught and schooled that trying to cut wood to tolerances of .001" was foolishness. However lately I have to agree that machine tolerances of that minute amount can be a good thing if it gives the wood worker more confidence and pride in his work.

We also need to be aware that machine tolerances of .001" can quickly become bad thing when the woodworker depends on the machine too much and forgets about the properties of the substance he is working with.

Are machining tolerances of .001" necessary? Absolutely not! If they were older antique wooden pieces of furniture, boxes, etc. would never have been made. The most important part of project making is the woodworker himself! Good quality machines are a help, but they will never become the total answer.

If one wants to rip,cross cut, dado, groove, rabbet to tolerances of .001" - Have at it. I hope it helps! But the most important issue in making a wood project is the woodworker's understanding of the properties of the wood he is working with and proven techniques of shaping, milling.

Even when a woodworker knows that wood will always change dimension as humidity changes, he can be led astray with rules of thumb. Some say that oak, for example, will change dimension tangentially 8% and will either avoid that wood, or try to allow for that much movement. The truth is - red oak will change dimension that much while changing only from "water saturation" to "oven dry" condition. The wood movement we actually experience, if not subject to a flood or other submersion, is a lot less.

I have calculated that an 8" wide flat cut of California red oak will change lateral dimension by 0.11" with a moisture content change of 6% to 12%, or vice versa. This movement is 0.96% of the original 8" width, not 8%. That computation is applicable only to purely tangential movement. If a portion of that board is rift grain the movement will be less. In any event it is to the woodworker's advantage to first look at his chosen wood and take his best guess on how much movement will likely occur given the use of his project.

Necessarily cutting to .001"? Not for me!

charlese wrote:Number 16 is an Excellent post! Thanks Ed!

Here's a soapbox I thought applicable to this thread...
...Necessarily cutting to .001"? Not for me!

Hi Chuck!
Here is my take...
Although I agree with you about not needing to have such close tolerances when woodworking, just for the sake of having them, I think that having the ability set your equipment to those high tolerances can be important. It is a question of repeatability. When assembling a project that requires many pieces of the same dimensions, usually you wood cut all the pieces at the same time, and therefore, you wood have what you need, all the same dimension. But what if you lose one? Break one? Miss count? Or any number of other things happen? I know, I know, you can duplicate another piece with out using high tolerance tools, but they sure make it easier/faster. And what if it was a whole series of parts that you needed to replace? Each individual replaced part takes time to duplicate. You know what I mean; you cut a replacement part, it is knot quite right, you trim it, sand it, and eventually get it just right. Now do that twice or three times, etc.

Even with expansion/contraction concerns, you want all the pieces to be the same to start with. That way they will all expand/contract equally (assuming a few other things, of course).

I bought the Incra set-up from SS through a Rick Davis TA. The way Rick presented it was impressive. I want to use it to make all of those fancy dovetails. He also showed how, if you did knot have a 520 table set up, you wood never need one, if you used the Incra fence on your 510.

Unfortunately, I have knot taken the time to install it yet. But I am in no hurry. I do knot seem to have a window of time equal to what I need to do that. I do knot want to rush it, and I have a lot of other things on my plate. I only get short periods of time in my shop, and I do knot want to start a project like that, which I wood have to leave laying unfinished in my shop, just to have to come back to time and again to finish it up. I want to do it all at once, or maybe in two sessions. I am knot yet retired, and will have more time on my hands when I am. If I get it set up before then, bonus!

Now, I have seen photos of many of your projects. Each one a masterpiece. You, I have no doubt, can use the tools that you have to great success. Me, well, I need all the help I can get!!:D

I can certainly agree with anyone that desires a specific tool or jig. It's a want thing! - Very personal! - Not arguable!

These days as we go about measuring computer bytes in Gigabytes, think of speed in nanoseconds, get exposed to machinery that will lift people into space, get introduced to tools that purportedly have adjusting specs that will allow thousandths of inches - it is no wonder we want such tooling. My point is: What is the use? Several hundred dollars in order to save a little time in a hobby? Okay! This is a personal thing and not argueable.

Doesn't that leave one to thinking - how did those Egyptian guys and the Inca guys build those exacting pyramids? What did they use for measurements? How did those old Romans and Greeks build those miraculous structures? What did they use for measurements? How did they ever get repeatability? I am told one way was with the use of story sticks and measuring bocks.

When repeating a cut in real wood, making an exact duplicate to the nearest thousandths of an inch is almost impossible even if cut using the same set-up. Only if the pieces have the same exact density - have the same exact distance between rings and the slope of annual rings is duplicated throughout the individual pieces - and only if there is absolutely no lateral movement of the saw blade, can this take place. These requirements will, in all practicality, never exist. The structure of wood, with all of it's variances, just will not allow it to be milled to and retain a specific size within tolerances of .001"

Okay! We're not talking about making individual pieces the same size with that .001" tolerance. We a talking about setting a machine to that tolerance in order to cut the wood. I must agree that is a good goal, and advertisments tells us, achievable! My question is - still - Why? If one can cut wood to the nearest (hundredth) 0.01" and it can then easily be further shaped or milled to fit in a project (called fitting), sawing to the nearest .001" becomes unnecessary.