520 Fence out of true

forrestb · Post by **forrestb** » Fri Nov 07, 2014 3:05 pm

In the process of re-aligning the 520 main table, I thought to check that the 520 fence was also parallel to the miter gauge slots.

Much to my surprise I found that the 2 ends of the fence stayed at 0 degrees from parallel but the portion over the quill was sunk in 0.008 away from the slot:

[ATTACH]26750[/ATTACH] [ATTACH]26751[/ATTACH] [ATTACH]26752[/ATTACH]

I have not contacted SS about this since my system is very old, but if one of you has I would appreciate hearing about their response - or maybe my fence is 'unique.':rolleyes:

Fortunately, I have made an auxiliary fence that will over come this.

Forrest

bffulgham · Post by **bffulgham** » Fri Nov 07, 2014 3:40 pm

Do you get a mirrored measurement if you measure from the right miter slot to the right side of the fence? e.g. .008" closer to the right miter slot than at the ends?

Just curious if the whole fence is bowed or only the one side....

I don't think .008" is going to make much difference in woodworking......
It's very close to 1/128" and that's pretty tough for my eyes to see.......
But, that's just me....

ldh · Post by **ldh** » Fri Nov 07, 2014 3:59 pm

forrestb wrote:In the process of re-aligning the 520 main table, I thought to check that the 520 fence was also parallel to the miter gauge slots.

Much to my surprise I found that the 2 ends of the fence stayed at 0 degrees from parallel but the portion over the quill was sunk in 0.008 away from the slot:

[ATTACH]26750[/ATTACH] [ATTACH]26751[/ATTACH] [ATTACH]26752[/ATTACH]

I have not contacted SS about this since my system is very old, but if one of you has I would appreciate hearing about their response - or maybe my fence is 'unique.':rolleyes:

Fortunately, I have made an auxiliary fence that will over come this.

Forrest

Check your fence with a good straight edge such as the Lee Valley or Starrett then the miter slot. I would be very surprised that the fence would be out by .008 in the middle. If it is out by that much I am sure Shopsmith would want to know.
LDH

forrestb · Post by **forrestb** » Fri Nov 07, 2014 4:08 pm

After saying on my last post that my auxiliary fence solves that problem I thought that I really should verify that.

Well, I could not because I got the same result with it. I moved the aux fence to the left side slot and found that the right hand miter slot is true within 0.001 from the beginning to the quill point and did not go out until the very end.

[ATTACH]26754[/ATTACH] [ATTACH]26753[/ATTACH] [ATTACH]26755[/ATTACH]

The aux fende was reversed going from one slot to the other so that I was tracking the same surface in both cases.

The Forum would not let me upload 6 files but here is the telling difference on the left miter gauge slot:

[ATTACH]26756[/ATTACH] [ATTACH]26757[/ATTACH]

The measurement went back to 0 degrees at the end. The results are the same as in my previous post for the left hand miter gauge slot.

So I am able to be as precise as I want by using the right hand miter slot and my fence. I have a couple of fixtures that use both slots so that is the next event.

I now think I will stop measuring and go do some woodworking.

Forrest

JPG · Post by **JPG** » Fri Nov 07, 2014 5:37 pm

I think the dial indicator is a good tool for making one paranoid.

Anybody checked the 'straightness' of the miter gauge slot in the table?:rolleyes:

I doubt SS would be alarmed over a .008 concavity of the fence.

dusty · Post by **dusty** » Fri Nov 07, 2014 6:15 pm

Forrest: My rip fences are not perfectly true either. I do not recall the numbers but I know they are not dead on.

I would strongly recommend that you check the fence using a quality straight edge and a feeler gauge. This would eliminate the miter track being a contributing factor - as JPG has eluded to.

How do you like the Woodpecker miter gauge that you are using for this. I am tempted to buy one but have not been able to justify it to myself since I already have the Shopsmith version.

forrestb · Post by **forrestb** » Sat Nov 08, 2014 12:14 pm

I used a straight-edge that I checked against the table top and could not get a 0.002 feeler gauge under it anywhere along the table.

I laid it on wood to get it to about the same height as the dial indicator was running and held it tight to the fence when measuring. Inaccuracies I'm sure, but as we said in the aerospace engineering community: 'close enough for government work.'

[ATTACH]26764[/ATTACH]

Hard to read but I essentially got the same result as with the dial indicator: 0.000 clearance at each end, 0.002 starting 4 inches end from each end and 0.010 in the middle.

I did not check from the 'back' side of the SS fence but will do that. I will shim my aux fence to eliminate the curvature of my SS fence and get on with life.

Dusty, see Woodworking Tool Review for a post on the Woodpecker dial indicator. It would hardly do to 'hi-jack' my own post!:eek:

Forrest

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