Rail square with repeat stop vs parrelle guides

[Jamool]

Hello all

I have some of the benchdogs.co.uk parallel guides which seem to work however the calibration seems bit of a pain. Currently getting around 1mm to half a mm out over a meter section.

How does a rail square with a repeat stop compare with parrelle guides? I assume when cutting out repeat components the rail square with the repeat stop achieves the same thing without the annoying calibration or so much variation?

Thanks for any help in advanced

 

[woodferret]

You trade the variability of independent parallels accuracy with the degree accuracy of the rail guide.  It'll be 89.95 to 90.05 off unless you're OCD meticulous. 

To remove the inaccuracy of two rulers, get a third one   Use one with a inside or outer slider block that you can mechanically reference to the parallel stops vis the splinter guard.  You may need to build a Z-shape jig that can transfer the splinter guard line up to the height of that ruler.  Of course, you'll need a clean precise splinter guard (which you probably would have redone anyways if you're needing this level of clean accurate cut).

 

[mikev12345]

I've always wonder about the accuracy of parallel guides and being about get them both to the same mark.  Its made me wonder if I should get dashboardpws rip guide (or DIY a version).  As [member=72072]woodferret[/member] said then you need to make sure your splinter guard is in good order.
https://www.dashboardpws.com/shop/rip-gauge

 

[fritter63]

You trade the variability of independent parallels accuracy with the degree accuracy of the rail guide.  It'll be 89.95 to 90.05 off unless you're OCD meticulous. 

To remove the inaccuracy of two rulers, get a third one   Use one with a inside or outer slider block that you can mechanically reference to the parallel stops vis the splinter guard.  You may need to build a Z-shape jig that can transfer the splinter guard line up to the height of that ruler.  Of course, you'll need a clean precise splinter guard (which you probably would have redone anyways if you're needing this level of clean accurate cut).

That is BRILLIANT! Another thing you could slide the two together and do similar where you like use a straight edge or even a clamp to make sure the stops are set the same, then slide it down to the other side.

I have to say that I've given up on using parallel guides (had the Festool ones and now I have the woodpeckers set). The problem is not the calibration of the setup, but the positioning of the stops. You have sight down the edge of the stop and decide if it's in the same place on the scale, which is what maybe .5 mm wide at least? And find myself trying to use the reflection of the scale marker on the stop, but it still never makes my OCD happy.

Full disclosure, these days if I'm making large panels (cabinets) I'm just gonna slap it down on the CNC and let it cut the whole thing out perfectly.

 

[mino]

...
To remove the inaccuracy of two rulers, get a third one
...

This is actually an excellent idea!

How about a PG setup without any marks, just simple screw stops. Setting up both /unmarked/ guides against the rail back using a simple ruler with stop on it and a calibration screw on the end. Hmm.

I believe you just designed my future PGs (!).

 

[woodferret]

Sometimes if I'm repeating a build, I just FU to the calibration/lines and use the existing stock as the setup block.  To avoid rail guide bend inacurracies, just use the same spot on the board to calibrate both PGs. 

The third rule thing was from Dan Pattison's homemade PGs.  He used the 'story stick' there.

 

[GregInVa]

I've always wonder about the accuracy of parallel guides and being about get them both to the same mark.  Its made me wonder if I should get dashboardpws rip guide (or DIY a version).  As [member=72072]woodferret[/member] said then you need to make sure your splinter guard is in good order.
https://www.dashboardpws.com/shop/rip-gauge

I have the Dashboard system and the advantage of the Rip guide is it offers a single point of reference versus having to adjust two parallel guides and hope you get them both dead on. It's less fiddly and more accurate.

greg