Author Topic: Is your DF500 90* positive stop really what you think it is?  (Read 3495 times)

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Offline ChuckM

  • Posts: 619
Someone recently told me the 90 degree positive stop on the fence is a hair past 90 degrees. I checked and indeed the stop does not set the fence square to the base!

What it means is that when I make a perpendicular/vertical cut, the mortise may not be dead perpendicular to the face/surface, if the fence is locked in its positive stop.

Instead of checking the fence every time for squareness, I used the precision square to set the base square to a flat surface, locked the fence, and then reset the angle pointer so I know when the pointer "splits" the incised 0* mark, I am mortising perpendicularly.

The first photo shows the precision square was checked against my reference square (0.00055" tolerance) before it was used.

The second photo shows that when I set the angle point to the 0* (split the mark), the base was verified to be perpendicular to the surface.
« Last Edit: September 03, 2018, 02:47 PM by ChuckM »

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Offline RobBob

  • Posts: 1314
Re: Is your DF500 90* positive stop really what you think it is?
« Reply #1 on: September 03, 2018, 03:07 PM »
This might explain it...if the link works.  I hope this helps.    [big grin]

DF500 tip

Offline Birdhunter

  • Posts: 2339
  • Woodworker, Sportsman, Retired
Re: Is your DF500 90* positive stop really what you think it is?
« Reply #2 on: September 03, 2018, 03:40 PM »
Great tip on the video. I guess I have “bumbled” my way into always getting the fence at 90 degrees by pure accident of not having the at the bottom.
Birdhunter

Offline Svar

  • Posts: 1472
Re: Is your DF500 90* positive stop really what you think it is?
« Reply #3 on: September 03, 2018, 04:28 PM »
This might explain it...if the link works.  I hope this helps.    [big grin]
DF500 tip
This tip has nothing to do with the OP's problem.

Offline ChuckM

  • Posts: 619
Re: Is your DF500 90* positive stop really what you think it is?
« Reply #4 on: September 03, 2018, 05:29 PM »
This might explain it...if the link works.  I hope this helps.    [big grin]
DF500 tip
This tip has nothing to do with the OP's problem.
You nailed it, Svar!

In fact, after watching the tip, I repeated the video procedures (raising and locking the fence a bit before tightening the fence at its positive stop. IT DIDN'T WORK for my DF500. The base was still not square to my flat granite surface (the video relied on a piece of wood as the reference face). I tried three times at different fence heights, and was still not getting perpendicular results.

See the attached photo, showing what happened to the base relative to a flat surface after following the video steps. You can clearly see the slight gap at the top, which disappears when I use my method as described in my first post.

May be you should try the video technique to see what result you get for your DF500.  For me, I will rely on the "split the mark" method for my vertical plunge cuts.

By the way, the granite surface was checked against a Bridge City Tools Work steel straight edge for flatness. The surface is as flat as, if not flatter than, any surfaced wood I can find in my shop.
« Last Edit: September 03, 2018, 05:42 PM by ChuckM »

Offline ChuckM

  • Posts: 619
Re: Is your DF500 90* positive stop really what you think it is?
« Reply #5 on: September 03, 2018, 06:03 PM »
I watched the video tip closely, and took a screenshot of the video just before it ended. It is attached in the pdf.

Offline Michael Kellough

  • Posts: 3536
Re: Is your DF500 90* positive stop really what you think it is?
« Reply #6 on: September 04, 2018, 12:32 PM »
Don’t forget that the mortise may or may not be absolutely parallel to the base.

Offline Kodi Crescent

  • Posts: 711
Does the variation from 90 degrees make any practical difference when using the Domino?

Offline ChuckM

  • Posts: 619
If the dominoes are long ones, non-perpendicular mortises in mating pieces could create unnecessary alignment issues or difficulty during assembly, or pull the carcass out of proper alignment depending on how many non-perpendicular mortises are in the mix. In a nutshell, non-perpendicular mortises create an additional layer of uncertainty in the work.

Imagine using the dowel joinery, and some of the mating holes drilled are not perpendicular.
« Last Edit: Yesterday at 06:56 PM by ChuckM »