dusty wrote:But the cut will be parallel to the right side of the jig (the miter slot).
Yes, the subject has changed slightly. That was the direct result of a response that enlightened me to the fact that the plate will not be in contact with the jig because of the offset in the teeth. However, the cutline remains parallel to the miter slot. Agree.
I'm debating (with myself) on your statement regarding the width of the kerf. To clarify, I think the kerf will be a constant width but wider than it would be if the blade were perfectly parallel to the miter slot. If perfectly parallel, the kerf should equal the advertised dimension of the blade, i.e. 1/8 or 3/32. When out of parallel, the blade cuts on both the front and back side making a wider kerf.
What I think we are setting up here is a kickback condition because either the jig or the cutoff (depending on table alignment) is going to be applying pressure to the blade. (Remember, I am in a personal debate). Agree if the out of parallel condition is bad enough.
I'm thinking the kerf will be a constant width yes, see my clarification above but no longer perpendicular to the leading or trailing edge of the jig I disagree here. The kerf will still be parallel to the miter slot and hence perpendicular to the leading edge if the jig is built perpindular (because the miter slot is no longer parallel to the blade). If we were doing a non-thru cut, this is what we would see. But if doing a thru cut, that kickback is about to occur.
This is why table alignment (to the blade) is so important.
After Thought: Actually, if doing a non-through cut, it will be a cove cut. yup.
Yes, I agree that the resulting kerf will be wider than the thickness of the blade. Thus a cove cut if this was a non-thru cut.
Please bare with me here. I am slow when I must envision these things. I have to touch and feel to grasp the facts.
I am still thinking about this statement. "I disagree here. The kerf will still be parallel to the miter slot and hence perpendicular to the leading edge if the jig is built perpindular"
Do we ALL agree that if the blade is parallel to the miter slot that the cut line will be perpendicular to the front rail and that if the table is misaligned (with respect to the blade) the cut line will no longer be perpendicular to the front rail.
"Making Sawdust Safely" Dusty
Sent from my Dell XPS using Firefox.
dusty wrote:Yes, I agree that the resulting kerf will be wider than the thickness of the blade. Thus a cove cut if this was a non-thru cut.
Please bare with me here. I am slow when I must envision these things. I have to touch and feel to grasp the facts.
I am still thinking about this statement. "I disagree here. The kerf will still be parallel to the miter slot and hence perpendicular to the leading edge if the jig is built perpindular"
Do we ALL agree that if the blade is parallel to the miter slot that the cut line will be perpendicular to the front rail and that if the table is misaligned (with respect to the blade) the cut line will no longer be perpendicular to the front rail.
If the table is out of alignment, you will be cutting with both the leading and one side of the trailing edge of the blade cutting. So, as best as I can picture it, in effect, a "wider" blade/wider kerf. So, I believe you will still have a perpendicular leading edge and the cut line will be parallel to the miter slot.
Bud F.
1998 Mark V 510 bought used 2006, Jointer, 2 Bandsaws, ca 1960 Yuba SawSmith RAS
Projects and "stuff": http://www.bfulgham.com/JAlbum/Woodworking_Index/
dusty wrote:Yes, I agree that the resulting kerf will be wider than the thickness of the blade. Thus a cove cut if this was a non-thru cut.
Please bare with me here. I am slow when I must envision these things. I have to touch and feel to grasp the facts.
I am still thinking about this statement. "I disagree here. The kerf will still be parallel to the miter slot and hence perpendicular to the leading edge if the jig is built perpindular"
Do we ALL agree that if the blade is parallel to the miter slot that the cut line will be perpendicular to the front rail and that if the table is misaligned (with respect to the blade) the cut line will no longer be perpendicular to the front rail.
Don't agree. I think that as long as you are using the miter slot to guide the piece and assuming the front rail is perpindicular to the slot (which it is unless the rails need shimming) you will always get a cut parallel to the slot and perpindicular to the rail only the kerf width will vary.
algale wrote:Don't agree. I think that as long as you are using the miter slot to guide the piece and assuming the front rail is perpindicular to the slot (which it is unless the rails need shimming) you will always get a cut parallel to the slot and perpindicular to the rail only the kerf width will vary.
OKAY I best not debate this. You seem confident in what you are saying so I am going to go off and draw some pictures and convince myself one way or the other.
The following being assumed as self evident. The blade does not move. It is the reference surface. The main table is moveable. Its position is moveable around the trunnion bolts approximately 1/16"' in any and all directions. The size of the holes in the trunnions limit how much the main table can be moved to achieve the desired parallelism.
"Making Sawdust Safely" Dusty
Sent from my Dell XPS using Firefox.
dusty wrote:OKAY I best not debate this. You seem confident in what you are saying so I am going to go off and draw some pictures and convince myself one way or the other.
The following being assumed as self evident. The blade does not move. It is the reference surface. The main table is moveable. Its position is moveable around the trunnion bolts approximately 1/16"' in any and all directions. The size of the holes in the trunnions limit how much the main table can be moved to achieve the desired parallelism.
Suppose that you removed the saw blade and mounted a router under the table. The spinning router bit has no preferred direction of cut.
Now feed a workpiece into the router bit, guiding it with your miter gauge. You will make a straight cut that is exactly parallel to the miter slot. No other surface is relevant.
Cutting with the saw blade is, in principal, the same. Except that to cut properly on through cuts, it must be aligned parallel to the miter slot, within a very small range.
dusty wrote:OKAY I best not debate this. You seem confident in what you are saying so I am going to go off and draw some pictures and convince myself one way or the other.
The following being assumed as self evident. The blade does not move. It is the reference surface. The main table is moveable. Its position is moveable around the trunnion bolts approximately 1/16"' in any and all directions. The size of the holes in the trunnions limit how much the main table can be moved to achieve the desired parallelism.
I shouldn't even respond to this, but here goes. Think of the front tires of an automobile. If the tires are "toed in" (out of align with the center line of the car and both leading treads of the tires are pointing more inward than forward) and the car is going in a straight line, the tire tracks will still be parallel with the movement of the car, but the tire track(s) will be wider because the tires are "skidding" thus doing the same thing as the leading and trailing kerfs of the blade.
My .02
Dick 1965 Mark VII S/N 407684
1951 10 ER S/N ER 44570 -- Reborn 9/16/14
1950 10 ER S/N ER 33479 Reborn July 2016
1950 10 ER S/N ER 39671
1951 jigsaw X 2
1951 !0 ER #3 in rebuild
500, Jointer, Bsaw, Bsander, Planer
2014 Mark 7 W/Lift assist - 14 4" Jointer - DC3300
And a plethora of small stuff .....
"The trouble with quotes on the Internet is that you can never know if they are genuine." - Benjamin Franklin
Consider a blade/miter slot grossly out of parallel, say the trailing edge of the blade is 1/8" closer to the miter slot.
Cutting using the miter gauge, or a work piece riding in the miter slot as pictured above will create a kerf 1/8" wider than the blade.
The leading edge will cut a fixed distance from the miter gauge slot. The trailing edge will also cut a fixed distance from the miter gauge slot, but 1/8" closer to the miter gauge slot.
Although this describes the goings on of a blade out of parallel with the miter gauge slot, it is impractical since the blade would jam unless the blade tooth set is greater than 1/16" on both sides.
I am not sure if this would create a potential kick back condition when using the miter gauge, but it would be cutting the workpiece with the rear edge of the blade cutting as it rises from below the table. If using the rip fence, a recipe for kickback since the closer trailing edge of the blade creates a pinch of the workpiece to the fence.
The reasons for setting the miter gauge slot and rip fence parallel to the blade are to minimize the kerf, eliminate the back edge nibbling on the workpiece and minimize possibility of pinching the workpiece between the blade and fence.
Cuts will always be parallel to the miter gauge slot(all else being equal).
This parallel setting is more critical if using a hollow ground blade with no/very little tooth set.
The rail perpendicular to the miter gauge slot is an independent 'adjustment'. Whatever it is will not change with parallel to blade adjustments.
The saw blade tooth set of a blade is the reason I usually use a sanding disk rather than a saw blade for table to blade adjustments. With either method, off flat condition must be accounted for.
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
JPG40504 wrote:The saw blade tooth set of a blade is the reason I usually use a sanding disk rather than a saw blade for table to blade adjustments. With either method, off flat condition must be accounted for.
Your prescribed method for checking flatness is?
SS 500(09/1980), DC3300, jointer, bandsaw, belt sander, Strip Sander, drum sanders,molder, dado, biscuit joiner, universal lathe tool rest, Oneway talon chuck, router bits & chucks and a De Walt 735 planer,a #5,#6, block planes. ALL in a 100 square foot shop. .
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Bob
JPG40504 wrote:
The saw blade tooth set of a blade is the reason I usually use a sanding disk rather than a saw blade for table to blade adjustments. With either method, off flat condition must be accounted for.
I think that Nick accounts for this in his method for checking alignment. I have the link (http://www.shopsmithacademy.com/SS_Arch ... gnment.htm)
where he says to mark one tooth, rotate it to the front to check distance then rotate that same tooth to the rear to check that distance. The only variable I see here is run-out of the quill.
But whatever works!
Forrest
Forrest
Huntington Beach, CA
1985 500->510->520, bandsaw, jointer, planer, PowerPro, double-tilt, 3" casters,(now obsolete) speed increaser
