Table saw set up, how accurate is accurate?

[Digit]

Agreed that the blade allignment is not an issue for mitre angle - but I'd qualify that by saying it IS an isse for a good mitre joint.

True! And any error is doubled when you offer the joint together, which is why I use a sled and cut one side of the mitre to the left of the blade and its mate to the right of the blade.
Provided the sled's included angle is 90 degrees, whether the cut angle is 45 or not doesn't matter.

Roy.

 

[BigShot]

Digit
Good point about the error being doubled. I'd thought about it but since all of this is pure theory to me at the minute I wasn't sure enough to include it.

As for the need for an accurate 45° mitre for picture frames... how good a fit does your method give? Below I've included another quick sketch to illustrate (with very exaggerated angles) what I'd see happening.
I assume you're still aiming for something pretty close to 45° - but how much room do you have before the error shown below becomes evident?

EDIT
I'm really quite upset with myself.
All these screen shots I've been posting today and the only nods towards Open Source software are the Thunderbird icon in my system tray, the GIMP item on the taskbar and a firefox shortcut.
AutoCAD (need it for work) IE (only using it and not firefox as I've got a ton of tabs open in FireFox and didn't want to wait for them to load) Adobe Reader (I'd sooner be using Xpdf, or better yet not using PDF at all) and Windows (Only using it at all because I work in AutoCAD! Otherwise I'd be in Linux!)... shocking. I need to see how the Archimedes CAD project is coming along - I'd love to switch to that some time and ditch Windows for good.

 

[Digit]

Assuming a 90 degree sled the frame angle will 90 degrees even if the cut to one side is 44 degrees, as 'tother side will be 46. Also it matters not if the blade is not truly vertical.
My sled base is made of Paxolin with two additional pieces of Paxolin screwed on to it, I had the local machine shop machine them to a 90 degree included angle on their milling machine.

Roy.

 

[Benchwayze]

Hi


I also don't want to have to redo it in a few weeks/months time because that will mean taking the cast iron wings and the rails off and having to redo the fence.

So is it accurate enough?

Mark

Hi Bear,

No matter how accurate you get the set-up, you are going to have to re-do this from time to time. Especially if you have only a smallish saw, and you run heavy lumps of timber through it. It's near-nigh impossible not to affect one setting or another in general use.

I check my saw every month, whether it needs it or not :lol: :lol: :lol:

Bester Luck
John

 

[The Bear]

Hi

Well this has got far more technical than I intended, a bit heavy after a 5am start this morning and a day at work. I am happy with the general principle as described however (I think ) and thanks to all for your input.

Obviousy I still want to strive to get it the best I can and wanted to know what others deemed to be accurate/acceptable.

As for redoing it, yeah I reluctantly accept I will have to do it many times. This is the first time set up and for my own curiosity I wanted to see how good I could get it. It is easier with all the bolt ons, not bolted on because it definitly isn't small.

Anyway I redid the mitre slot again, same accuracy as before, also got the rails on and the running bar for the fence. Time to adjust the fence - I guess a similar accuracy to the blade is what I should be aiming for :? ?

Anyway can't do it tonight as I need to get an imperial allen key to adjust it
:roll:

Mark

 

[Benchwayze]

Well Mark,

You will be glad you took the trouble. Imperial Allen Keys? I didn't know there were any other sort. :lol:

Until I was given a huge platic case full of drills, bits, drivers , sockets, etc all to fit into my drill/driver! There were some metric ones an there! Well all I need now are some metric socket bolts!

All the best.
John