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Discussion Starter #1
I'm referring to the 5 cut method.

I've been trying to zero in on the fence being square and boy has that been a bugger. I've drilled so many holes under it I'm running out of places to drill (this is just a small sled).
I did have it down to around .001"s but when I put in the rest of the support screws it ended up being .0027".

My question, is that good enough?

Bryan
 

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Discussion Starter #3
Thanks Gary.

Maybe I'll turn the sled around making the back the front and try it again later. I need a break right now, I'm tired.


Wait, I do already have the back on mounted with several screws. I'll have to look at and see if I have more room for holes.
 

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Bryan; I think the simple solution is to use a small slot in one of the components allowing the fence to pivot slightly. When you get it where you want it you tighten it down, and put in the remaining screws to lock it in place.
Essentially two screw holes and one slotted hole, in the length of the fence.
 

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Discussion Starter #5
Bryan; I think the simple solution is to use a small slot in one of the components allowing the fence to pivot slightly. When you get it where you want it you tighten it down, and put in the remaining screws to lock it in place.
Essentially two screw holes and one slotted hole, in the length of the fence.
I'll look at that idea and see if I can do it. I did have it dialed in at around .001"s but it didn't hold when I put in the other screws. Maybe the two screws weren't tight enough. I would like to get it closer so I'll try it again.
My base isn't very big so I'll look at what Baltic Birch I have left in case I need to start over.
I'm also building a large sled and what I learn with the small one should help there.

Thanks for the suggestion,

Bryan
 

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*Bogglement*
Bryan; are you saying your tolerance after doing the 5 cuts is +/- .001" ?!
Holy Hanna! You wanna make me one? Please!! ;)
 

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Stop!
I'm doing a treatise on measurement and woodworking.
There are so many variables with respect to this squaring method; don't waste your time.
You cannot measure wood to .001".
There is stress relief, fuzz, dust, face tearout, saw chatter +....all frustrate getting the same measurement twice in the same place.

Your vision, parallax, your measuring tools and your skills at reading (& using) them play a part. Do you read from the centerline of the fiducials (rule etchings), the space in between, or both. It makes a difference. Starrett rules are calibrated on the line centerlines. The space between the lines, depending on the increment, is only an estimation! Calipers, travel and ht. gages are accurate but is your work cut accurately enough to use them? Is the work flat, measured on a reference surface, etc?

Moreover, the health of your saw system, saw blade (twisting/bending, sharpness), feed rate and the anisometry (directional dependency) of wood are dependent variables to contend with too. The dynamics of the saw blade in a x-cut are different than a rip. This is crazy.

Just set your sled to squareness (as best you can) and take a cross cut on something 8-12" wide, starting with a very straight edged & precisely parallel stick. The fence on the sled has to be within +/- .001 or better in flatness and straightness for starters. The work has to be clamped; it cannot squirm. Use a machinist's square on the cut stock and do your best to investigate it.

Check this from time to time, maybe keep samples and dates, but don't get crazy over this foolish squaring technique; it's a guess.
 

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Discussion Starter #8
*Bogglement*
Bryan; are you saying your tolerance after doing the 5 cuts is +/- .001" ?!
Holy Hanna! You wanna make me one? Please!! ;)
Dan, not exactly but I had at .001 until I added more screws for support, that's when it moved to .0027"s. I used Dr Ny's video for the 5 cuts and adjusting.

On another note here-
Below in this post I found this and pasted it here from Quillman and I'm mentioning it here because I couldn't see this post while just reading all of the other post. I only saw it after I quoted you Dan, then I ran down the page and saw Quillman's reply.
I'm wondering if this has happened before, maybe I've missed other post.

Can you or anybody else see Quillman's post in the main body of the string of replies?

Here's is what I cut and paste from Quillman's post.

"Quillman Stop!
I'm doing a treatise on measurement and woodworking.
There are so many variables with respect to this squaring method; don't waste your time.
You cannot measure wood to .001".
There is stress relief, fuzz, dust, face tearout, saw chatter +....all frustrate getting the same measurement twice in the same place.

Your vision, parallax, your measuring tools and your skills at reading (& using) them play a part. Do you read from the centerline of the fiducials (rule etchings), the space in between, or both. It makes a difference. Starrett rules are calibrated on the line centerlines. The space between the lines, depending on the increment, is only an estimation! Calipers, travel and ht. gages are accurate but is your work cut accurately enough to use them? Is the work flat, measured on a reference surface, etc?

Moreover, the health of your saw system, saw blade (twisting/bending, sharpness), feed rate and the anisometry (directional dependency) of wood are dependent variables to contend with too. The dynamics of the saw blade in a x-cut are different than a rip. This is crazy."

Just set your sled to squareness (as best you can) and take a cross cut on something 8-12" wide, starting with a very straight edged & precisely parallel stick. The fence on the sled has to be within +/- .001 or better in flatness and straightness for starters. The work has to be clamped; it cannot squirm. Use a machinist's square on the cut stock and do your best to investigate it.

Check this from time to time, maybe keep samples and dates, but don't get crazy over this foolish squaring technique; it's a guess.
 

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Discussion Starter #9
Quillman,

Sorry Quillman, I can't see your post in with the other post. I did see it when I started to reply to Dan with his quote, that's where I saw your post.

Is a machinist square one of those little squares with no writing on it (maybe 6")? Well, it may have writing but from seeing them in pictures
they look like there's nothing on it.

Anyway, is that what you think I should be doing instead of going through this 5 cut and calculation process?

Bryan
 

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Ok everybody, sorry, now I see Quillmans post. It must have been lost in space.


Bryan
Bryan, Pat has some sage advice. It amazes me, that, woodworkers try and hold their dimensions to the same tolerances as a machinist! While I, like others, tend to hold to as tight a fit as I can it is not all that critical.

The diameter of human hair varies from 17 to 180 micrometers (0.00067 to 0.00709 in).

0.001" is seven times finer then the size of a thick human hair.

Guess what? Glue, sawdust and finish can fill this void and no one but you will ever notice or even care.
 

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Bryan, Pat has some sage advice. It amazes me, that, woodworkers try and hold their dimensions to the same tolerances as a machinist! While I, like others, tend to hold to as tight a fit as I can it is not all that critical.

The diameter of human hair varies from 17 to 180 micrometers (0.00067 to 0.00709 in).

0.001" is seven times finer then the size of a thick human hair.

Guess what? Glue, sawdust and finish can fill this void and no one but you will ever notice or even care.
excellent analogy...

.


.
 

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Stop!
I'm doing a treatise on measurement and woodworking.
There are so many variables with respect to this squaring method; don't waste your time.
You cannot measure wood to .001".
There is stress relief, fuzz, dust, face tearout, saw chatter +....all frustrate getting the same measurement twice in the same place.

Your vision, parallax, your measuring tools and your skills at reading (& using) them play a part. Do you read from the centerline of the fiducials (rule etchings), the space in between, or both. It makes a difference. Starrett rules are calibrated on the line centerlines. The space between the lines, depending on the increment, is only an estimation! Calipers, travel and ht. gages are accurate but is your work cut accurately enough to use them? Is the work flat, measured on a reference surface, etc?

Moreover, the health of your saw system, saw blade (twisting/bending, sharpness), feed rate and the anisometry (directional dependency) of wood are dependent variables to contend with too. The dynamics of the saw blade in a x-cut are different than a rip. This is crazy.

Just set your sled to squareness (as best you can) and take a cross cut on something 8-12" wide, starting with a very straight edged & precisely parallel stick. The fence on the sled has to be within +/- .001 or better in flatness and straightness for starters. The work has to be clamped; it cannot squirm. Use a machinist's square on the cut stock and do your best to investigate it.

Check this from time to time, maybe keep samples and dates, but don't get crazy over this foolish squaring technique; it's a guess.
Pat: every woodworker that agonizes over their crosscut sleds or tolerances in general needs to read your post.

Bryan:

I posted some pics in another thread of yours. It's the method I used when I made my sled. I lock down one end of the sled's fence, then using a dial indicator and a machinist square on the "loose" end, I slide the sled so that the machinist square rides along the dial indicator. If the indicator barely moves, I lock down that end of the fence. Good enough for my woodworking.
 

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At .0027, I'd call it good. William Ng tries for .001 (1 mil) but in one of his videos, he admits that a couple of mils isn't worth sweating over.

I'd worry over 10 mils, work to get 5 mils out but 1 or 2, you are at the point of diminishing returns.
 

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Discussion Starter #16
At .0027, I'd call it good. William Ng tries for .001 (1 mil) but in one of his videos, he admits that a couple of mils isn't worth sweating over.

I'd worry over 10 mils, work to get 5 mils out but 1 or 2, you are at the point of diminishing returns.
Thank you Phil. Dr Ny did say not to sweat it but in the video I saw I didn't pick up on just how tight it should be.

Bryan
 

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Discussion Starter #17
Pat: every woodworker that agonizes over their crosscut sleds or tolerances in general needs to read your post.

Bryan:

I posted some pics in another thread of yours. It's the method I used when I made my sled. I lock down one end of the sled's fence, then using a dial indicator and a machinist square on the "loose" end, I slide the sled so that the machinist square rides along the dial indicator. If the indicator barely moves, I lock down that end of the fence. Good enough for my woodworking.
Vince, I found your post in that marathon thread "Table Sled Runners" and I understand how you do it, it did make sense.
I did pick up a dial indicator but no mounting hardware yet so I'll have to get to that as well as getting a machinist square.

Bryan
 

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Discussion Starter #18
Bryan; you probably made the connection between 'Quillman' and Pat Warner, but just in case you had any doubts about Pat's uh, experience...
ROUTER WOODWORKING

When it comes to precision, he's a Guru! :)
Dan,

Nope, I didn't make that connection though I did recognize his site from the link, I have been there. I saved it to Favorites for future reference. I still don't have everybody figured out.

Thanks for the clarification and the link.

Bryan
 

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Bryan

If you've got the dial indicator, mount it on a wooden runner - here's a link to a site that shows you how:

Dial Indicator Jig - NewWoodworker.com LLC

You don't need a machinist square - you must have a combination square in your shop. Just make sure it "is square". You can check it by the reverse method. First put your square against an edge and strike a line, then flip the square, strike another line close to the first line. If the two lines are parallel, then your square is "square".

You don't need fancy equipment, you just need to improvise.
 
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