Miter gauge 'Alignmnent'

JPG · Post by **JPG** » Sun May 06, 2012 4:08 am

This subject was touched upon the other day with questions regarding washer sizes, and I do not recall any follow up.

That is understandable! Who ever thinks about 'aligning' a miter gauge? Other than stops for 45 and 90 degrees cuts, what is there?

Well now that depends upon what you expect it to do. I expect it to be not only accurate for those 45/90 degree cuts, but non-obtrusive in its use. It should glide easily across the table when used and be unambiguous in holding the workpiece.

Does that happen magically? NO!

So what is there to consider/tweak? First of all there is the miter bar. Is it straight? Not so much a width question as up/down from end to end. Mine(3) may have been straight at one time, but are not so today(I only have historical knowledge of one of the three and I have no idea how it got 'unstraight'). What does this matter? Depends upon if you like a teeter-totter action when using it. The newer bars with the washer and new table slot at least have a built in 'limit'. Not so with the older hardware. Why do we worry about the teeter-totter action? Other than the feeling of instability, there is the fact the front face of the miter gauge is tilting slightly which also causes the work piece to tilt likewise(maybe). When using the 'safety clamp' the tilt is almost guaranteed since the workpiece is being held tightly against the top of the bar.

So where is the teeter-totter pivot? A couple of things called glides. They protrude slightly from the bottom of the casting and provide the 'slick' low friction surface that rides on the table top. How far should the glides extend beyond the bottom? Just far enough to not allow any part of the gauge to drag.

Washers: only two affect any alignment(the two under the angle lock knob do not affect alignment). One washer is under the protractor pivot and should provide sufficient clearance between the casting and the bar. Ideally that clearance should coincide with the glide clearance with the bar bottomed out in the slot. If the bar does not bottom out(almost since we do not want the bar to be dragging the bottom of the slot), the teeter-totter returns. The second washer spaces the protractor lock so it does not interfere with the table. Assuming the casting surfaces are co-planer, the same thickness washer should be used both places. Also those washers should be thinner than those used under the lock knob. If the preceding is correct, the face of the gauge should be square vertically with the top surface of the bar.

So what effect does the 'verticalness' the gauge face have to do with accuracy? None IF the table is not tilted or the gauge set off 90. Then it can have a slight effect. I would expect the teeter-totter to contribute a very small error.

So after all this thinking(?) out loud, what is there to 'align'?

1. 45/90 degree stops.
2. Glide protrusion.
3. Make sure proper washers are installed correctly.
4. Try to keep the bar from getting 'unflat'.

Excessive glide protrusion will increase the teeter-totter effect. Insufficient glide protrusion will result in dragging against the table top. The washers between the bar and the protractor should just provide bar to bottom of slot clearance with the glides properly adjusted(yes some inter-dependance here).

Ideally the bar will slide in the slot with no particular tendency to bottom out in the slot or the top of the washer(newer version) dragging.

Billdit · Post by **Billdit** » Sun May 06, 2012 7:54 am

How about amounts in thousands ? I don't know if my opinion of "Sufficient" and yours would be the same, for instance.

Bigger question is... when do you sleep ??

JPG · Post by **JPG** » Sun May 06, 2012 11:10 am

Billdit wrote:How about amounts in thousands ? I don't know if my opinion of "Sufficient" and yours would be the same, for instance.

Bigger question is... when do you sleep ??

If 'dragging' occurs clearance is 'insufficient'. If it doesn't occur, clearance is sufficient!

At times I am awakened in the middle of the wee hours to attend to swmbo and at times stay up for a short period. Hopefully some coherence also occurs! I hesitated doing this due to lack of potential need/relevance, but went ahead anyway!

saminmn · Post by **saminmn** » Sun May 06, 2012 12:13 pm

Sorry I had not posted a follow up on my thread. I got everything set as you have describe here. But, I had to over-extend the guides about a 1/6 of a turn to keep from having the miter bar hit/drag on the table bar that the rip fence rides on. This creates a small amount of teeter-totter effect.

When last I posted to that thread, I was planning to lower the table bar. I have not gotten in and done this yet...maybe that is not a good solution. I like your idea of checking that miter bar is flat.

Are wear marks, on table bar where the miter bar crosses, common? These wear marks were present when bought from PO.

JPG · Post by **JPG** » Sun May 06, 2012 12:40 pm

saminmn wrote:Sorry I had not posted a follow up on my thread. I got everything set as you have describe here. But, I had to over-extend the guides about a 1/6 of a turn to keep from having the miter bar hit/drag on the table bar that the rip fence rides on. This creates a small amount of teeter-totter effect.

When last I posted to that thread, I was planning to lower the table bar. I have not gotten in and done this yet...maybe that is not a good solution. I like your idea of checking that miter bar is flat.

Are wear marks, on table bar where the miter bar crosses, common? These wear marks were present when bought from PO.

Since the bar clears the rail by a very small amount, the bar sliding on the top of the rail is possible, but I suspect it is more likely that a PO was dragging the bar across the rail when inserting it into the slot(especially if the PO were of short stature;)).

One more drag possibility. The very end of the bar has the pointer and safety clamp handle mounting block. Older versions had very little clearance between the bar and the block. Newer versions have reliefs milled into the sides of the block at the bottom where it attaches to the bar.

Finally any burrs etc. on the bottom of the bar can scrape across the rail. If those burrs are towards the center of the rail, the extra clearance in the table slot center will allow those burrs to miss dragging on the table.

saminmn · Post by **saminmn** » Sun May 06, 2012 3:51 pm

I checked flatness of the bar and it is not quite flat. I put the guides where the miter bar was down, i.e. some side to side wobble. The heavy end withe the protractor sat on the sides of the bottom of the miter slot while the other end was just above the table surface, maybe 1/64th inch,certainly not more than 1/32".

Next I set the guides to remove side to side wobble. I happened to use the right miter slot this time. I found that the miter bar only drags on rail when in the left miter slot. It is ok in the right slot. So, holding the miter gauge by the protractor getting ready to adjust for the left slot, I noted that the slot in the guides are about on 1-7 o'clock angle if you think of the miter bar as running along a 3-6 o'clock line. Backing out the guides to a minute or two before 12 o'clock gets rid of dragging on the left rail. Pressing behind the protractor face on the miter gauge/bar raises the far end of the bar less than a 1/16". So the out of vertical back at The protrator face should be minamal.

I think I will have to lower the left end table bar (or rail if that is what it is called). The other thing I had noticed about my miter gauge was that the left miter slot is more of a snug fit than the right.

JPG · Post by **JPG** » Sun May 06, 2012 11:18 pm

saminmn wrote:I checked flatness of the bar and it is not quite flat. I put the guides where the miter bar was down, i.e. some side to side wobble. The heavy end withe the protractor sat on the sides of the bottom of the miter slot while the other end was just above the table surface, maybe 1/64th inch,certainly not more than 1/32".

Next I set the guides to remove side to side wobble. I happened to use the right miter slot this time. I found that the miter bar only drags on rail when in the left miter slot. It is ok in the right slot. So, holding the miter gauge by the protractor getting ready to adjust for the left slot, I noted that the slot in the guides are about on 1-7 o'clock angle if you think of the miter bar as running along a 3-6 o'clock line. Backing out the guides to a minute or two before 12 o'clock gets rid of dragging on the left rail. Pressing behind the protractor face on the miter gauge/bar raises the far end of the bar less than a 1/16". So the out of vertical back at The protrator face should be minamal.

I think I will have to lower the left end table bar (or rail if that is what it is called). The other thing I had noticed about my miter gauge was that the left miter slot is more of a snug fit than the right.

Please explain!

I wonder how 'flat' the bottoms of the glides are. Back when they were merely 5/16-18 nylon screws, flatness mattered not.

We are dealing with a 500 still?

saminmn · Post by **saminmn** » Mon May 07, 2012 12:38 am

I had turned the guides so they weren't supporting the protractor to check for flatness, hence the wobble. So I mean that I was doing part 2 of the alignment you mentioned in first post.

JPG · Post by **JPG** » Mon May 07, 2012 12:51 am

saminmn wrote:I had turned the guides so they weren't supporting the protractor to check for flatness, hence the wobble. So I mean that I was doing part 2 of the alignment you mentioned in first post.

The way to check for flatness of the bar is to set it against a known flat/straight surface/edge.

danscot · Post by **danscot** » Mon May 07, 2012 9:25 am

Well, it looks like I'm at the same point as Sam in MN in getting a SS back into action. I'm having "fun" with the Miter Gauge too

so it seems appropriate to add my questions here.

I stripped & cleaned it & now that its back together my big problem is with the Nylok screw attaching the bar to the protractor at the pivot point. Prior to cleaning, I'm sure I checked it and was able to change the angle without the Nylok screw moving with the bar & coming undone. Post re-assembly it just won't stay tight. Have I "cleaned" off some special coating - I recollect brushing off a powdery material that I thought was oxidised aluminium. I'd appreciate suggestions for solving this issue.

I also have doubts about the washers so confirmation that they are the original parts would help. The sizes I have are:
ID: both 1/4"
OD: both 5/8"
Thickness: 277 Special Washer: 1/32"; 269 Washer: 1/16"

[ATTACH]17379[/ATTACH]

This pic shows (L to R) the Nylok screw, 269 washer, 277 washer from the pivot point & the 277 stuck at the base of the lock knob stud. I have only that one 269 washer under the lock knob, the exploded view in the manual shows 2. Is there a particular reason for 2 as this doesn't seem to affect the function?

The special washer at the base of the Miter Stud (278) is firmly stuck to the Bar, so much so that I initially thought it was machined as part of the Bar. It's also showing signs of wear from the protractor travelling over it. It's either completely rusted on or the Miter Stud is locking it on. Is there a way to remove the Miter Stud from the Miter Bar to release that washer? ( in a non-destructive way! I'll have to put it all back again).

On top of all that, with the Nylok screw tight the Protractor hits the edge of the table when sliding it in; when the screw has slackened off after setting an angle it glides smoothly over the edge. Marks on the table edge suggest the PO suffered this for some time. I'm hopeful that the solution to this lies in solving one or more of the questions above. Either that or I may have to use a thicker washer between the protractor & bar at the Nylok screw. Note that my bar is perfectly flat.