TSO parallel guide system inaccurate metric scale?

[thudchkr]

Moving on to my fixed rules, here are the results.

Woodpecker aluminum rules.

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Some variance noted here but I wonder if the temp in the shop were higher, would they then match up exactly?  May play more with these to see if and how different temps affect their accuracy.  I did use the attached hookstop on each of these during my comparison.

A Starrett 23.5"/600mm rule in a combination square.

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The photo didn't come out as well as the comparison between the two.  It matched very well, but I failed to capture that comparison as I tried aligning the two for the photo.

 

[thudchkr]

A Shinwa 600mm stainless steel rule purchased on Amazon.

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Good accuracy for the price.  I wouldn't hesitate to recommend this to others

And lastly, a 1m rule in stainless steel from Lee Valley.

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Slight variance noted here, but probably .2mm at the most.  Again, a good value for the money.

All in all, I'm relatively happy with the tools I currently have.  I don't trust my Woodpecker rules to measure the same as my other tools, and feel that as the temp changes, they will probably move a bit as well. 

Very pleased with my Tajima's as they are my favorites to use.  I do plan on putting the Class 1's away in a drawer and using them more as a reference, than as my everyday tapes. 

Hope this helps, and feel free to ask questions.

 

[ChuckM]

Is it an angle issue? Interesting that it's dead-on at 90, but way off elsewhere.

 

[Michael Kellough]

Is it an angle issue? Interesting that it's dead-on at 90, but way off elsewhere.

It’s a parallax issue. The Woodpecker rule is too thick.
The tape rule should overlap the Woodpecker rule rather than the other way round.
They’ll probably match well then.

 

[thudchkr]

Is it an angle issue? Interesting that it's dead-on at 90, but way off elsewhere.

It’s a parallax issue. The Woodpecker rule is too thick.
The tape rule should overlap the Woodpecker rule rather than the other way round.
They’ll probably match well then.

Agreed on the parallax. Hard to hold them steady and get a good pic when you don’t have a second person  [huh]

 

[ChuckM]

Masking tape is your third hand.

 

[Packard]

A few years ago I bought a Woodpeckers T-square (oversize, I don't recall the size right now).

I just checked with our QC manager and we have a calibrated vernier caliper that measures up to 24". 

I will bring in the T-square and ask him to check a few dimensions to see how accurate it is.

I planned on giving this square hard use, but I bought a TSO square arm and I think I've only used the T-square twice.  It sits in the MDF holder hanging on the wall. It looks nice. 

I will have it checked and report our QC manager's findings.

In case you are wondering, you can get your own 24" Starrett vernier for just $1,600.00.  (I'll just ask the QC manager for results.)
https://www.transcat.com/starrett-123emz-24-50538-50538?st-t=adword_google_*&utm_source=google&utm_medium=cpc&adpos=&scid=scplp123EMZ-24&sc_intid=123EMZ-24&gclid=EAIaIQobChMIjcXKr9_d8QIVAfSzCh0KyQ53EAQYAyABEgKrZPD_BwE

 

[Festdewalkita]

I had noticed a discrepancy between my Fatmax tapes (35 foot and a 8m/26ft) and a Johnson Level 8m/26ft.  When I got my Fastcaps True32 and 5m/16ft, they seemed to match the Johnson Level.

Looking at this thread, I compared a Woodpecker SERX-36 to my TSO parallel guides, and they do not match over 36"...with the Woodpecker being barely a bit longer (I mean *just* barely).

Everything is a little bit off.

I saw this, so we're not alone: https://www.popularwoodworking.com/cnc/precision-instruments-woodworkers-part-two-rules-tapes/

Good luck finding Fisco tapes here in the States, but Tajima's SigmaStops are made in Japan and available here in the US at acmetools, among other non-jungle retailers.  I'll probably order several imperial and imperial/metric.

As to accuracy, I've got a Mitutoyo 500-197-30 (no cert) caliper that says 150.00 mm while:
TSO parallel guide 50" calls it 150.00mm
Fastcap True32 calls it 150.04
Fastcap 5m/16ft is calling it 149.67mm;
Johnson Level 8m/26' is calling it 150.11,

On the accuracy of the imperial, 6.0000 inches on the Mitutoyo:
TSO parallel guide 50" calls 6.0000"
Serx-36 calls it 5.9950”
Fat35 =5.9850”
Fat 8/26=6.0055”
Johnson Level 8m/26'=6.0100”
Fastcap5/16=5.9950”

These differences are minuscule, and subject to parallax/eye dominance, lighting, contrast, etc.

YMMV.