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Dial Indicator Jig for Table Alignment ?
Posted: Wed Mar 21, 2012 2:31 pm
by mountainbreeze
Just wanted to get some feedback on my idea of a jig for a dial indicator used to align the table and fence. It seems to me the object is to ensure the jig follows the miter slot perfectly with no play as you move it forward and backward in the slot. I accomplished this by creating a wedge that rides the corners of the slot. It seems to provide zero play since the wedge always situates itself down in the slot. The screw head seen on the underside rides along the table surface and ensures no "drop-off" when slid over the insert plate. I'd probably replace it with a nylon screw when I can find one.
So what do you think?
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Posted: Wed Mar 21, 2012 3:29 pm
by dusty
That should work great but if it does not it might be because the miter bar does not stay down in the miter track.
If that be the case, recut the miter bar to be a firm fit.
Good Job.
Posted: Wed Mar 21, 2012 4:18 pm
by JPG
dusty wrote:That should work great but if it does not it might be because the miter bar does not stay down in the miter track.
If that be the case, recut the miter bar to be a firm fit.
Good Job.
I agree! Nicely done!
I would first try cutting the miter bar with one flat side and the opposite beveled at a steeper angle. That allows the bar to ride one side of the miter slot(not just the corner edge) and the steeper bevel helps hold it there. Not sure which orientation would work better. Push one way, pull the other. Since holding it down on the table is required, then 'push' be better(flat towards the blade side of the miter slot).
The screw hole holding the gauge needs to be 'play' free. The gauge mounting hole is I assume a bit oversize as well. The lock washer may be a source of future consternation.
Dial Indicator Jig for Table Alignment?
Posted: Wed Mar 21, 2012 6:11 pm
by dusty
I suggest that you adopt a standard for precision
before you start doing Main Table Alignments. You can drive yourself nuts trying to get it right on.
I accept .005" as close enough for my wood working.
While working on Table Alignment, don't forget about your miter gauge. It needs to be set as accurately as does the fence-to-blade setting.
I use a tool called "MiterSet" to set my Shopsmith Miter Gauges. For a short while I double checked their positioning using a Wixey Angle Gauge but I soon come to realize that that was unnecessary. The Wixey never revealed an error after setting the miter gauge with the "MiterSet".
www.miterset.com
I use the MiterSet Standard for Shopsmith but if you do any segmented turning there is a more versatile version that you might want to consider.
Posted: Thu Mar 22, 2012 9:29 am
by mountainbreeze
After using it for a while, I find it works great. There is no tendency for it to come out of the miter slot when moving it forward and backward and there is virtually no play between the jig and the slot. The only play I observe is what is typically seen when simply pressing on the table.
I like the single bevel idea. I may try that if I make another one but this one seems to be working well for now. The first one of these I made had only a 5° bevel on both sides and that tended to wedge itself into the slot making it very difficult to slide. This one is two 45° bevels. I suppose something around 25° or 30° would work well also.
Thanks for the feedback.
Posted: Thu Mar 22, 2012 9:57 am
by dusty
mountainbreeze wrote:After using it for a while, I find it works great. There is no tendency for it to come out of the miter slot when moving it forward and backward and there is virtually no play between the jig and the slot. The only play I observe is what is typically seen when simply pressing on the table.
I like the single bevel idea. I may try that if I make another one but this one seems to be working well for now. The first one of these I made had only a 5° bevel on both sides and that tended to wedge itself into the slot making it very difficult to slide. This one is two 45° bevels. I suppose something around 25° or 30° would work well also.
Thanks for the feedback.
How close were you able to make your alignment?
As I said, I believe anything better than +-.005" is "right on".
Posted: Fri Mar 23, 2012 12:18 am
by eagleta2
I made basically the same tool by mounting the indicator to a spare miter bar. Yours is by far prettier though:D
What I wanted to mention was a problem I noticed. The tool worked great for aligning the table to the blade. I indicated off of one carbide tooth of a blade and aligned using the same tooth. Got the table aligned to. 002 +/-.
Then I went for the fence and for the life of me couldn't get it straight. After a couple hours I finally realized the problem. The face of my fence is not dead flat.. I can start off at 0.000 on the front edge of the fence and watch the indicator dance all the way down the length of the fence. I ended up aligning it using the “dusty method". It indicates as being off by. 040...but we will see how it cuts when I'm done with the pm on my head stock.
I just wanted to warn you about the face of your fence. Please let me know how your dial indicator works for aligning the fence. I have a 510 fence...which is inherently difficult to align IMHO.
Thanks
Geo
Posted: Fri Mar 23, 2012 12:24 am
by JPG
eagleta2 wrote:I made basically the same tool by mounting the indicator to a spare miter bar. Yours is by far prettier though:D
What I wanted to mention was a problem I noticed. The tool worked great for aligning the table to the blade. I indicated off of one carbide tooth of a blade and aligned using the same tooth. Got the table aligned to. 002 +/-.
Then I went for the fence and for the life of me couldn't get it straight. After a couple hours I finally realized the problem. The face of my fence is not dead flat.. I can start off at 0.000 on the front edge of the fence and watch the indicator dance all the way down the length of the fence. I ended up aligning it using the “dusty method". It indicates as being off by. 040...but we will see how it cuts when I'm done with the pm on my head stock.
I just wanted to warn you about the face of your fence. Please let me know how your dial indicator works for aligning the fence. I have a 510 fence...which is inherently difficult to align IMHO.
Thanks
Geo
I would find the two highest points on each end and align to them.
Posted: Fri Mar 23, 2012 5:43 am
by dusty
eagleta2 wrote:I made basically the same tool by mounting the indicator to a spare miter bar. Yours is by far prettier though:D
What I wanted to mention was a problem I noticed. The tool worked great for aligning the table to the blade. I indicated off of one carbide tooth of a blade and aligned using the same tooth. Got the table aligned to. 002 +/-.
Then I went for the fence and for the life of me couldn't get it straight. After a couple hours I finally realized the problem. The face of my fence is not dead flat.. I can start off at 0.000 on the front edge of the fence and watch the indicator dance all the way down the length of the fence. I ended up aligning it using the “dusty method". It indicates as being off by. 040...but we will see how it cuts when I'm done with the pm on my head stock.
I just wanted to warn you about the face of your fence. Please let me know how your dial indicator works for aligning the fence. I have a 510 fence...which is inherently difficult to align IMHO.
Thanks
Geo
To deal with an out of true fence, I would build a saddle to sit down over the fence. The two pieces that are to become the face can be trued before they are assembled.
To align the fence, I have cut a hard wood runner that is about 1" tall and fits snuggly in the miter track. To align the fence, I loosen all four screws, set the fence in place on the table, slide it up tight against that runner, clamp it there and tighten the four screws. Repeat if necessary - likely won't be.
If you have a bowed fence, you'll spot it doing this.
Posted: Fri Mar 23, 2012 9:17 am
by mountainbreeze
dusty wrote:How close were you able to make your alignment?
As I said, I believe anything better than +-.005" is "right on".
I got lucky I think. With the bolts loose, I aligned the table to the blade to about .003". After tightening the bolts it landed at .002".
As for the fence, no adjustment was necessary. On the left side of the fence, the dial indicator wavers ever so slightly +/- .002". On the right side, it's a different story - much wider variations as I move along the fence with the far end .004" different from the near end.
I think this all falls within acceptable tolerances.