should a protractor head read like this?

[Craig Behnke]

just got a protractor head, when i look at the degree scale with the locking nut facing up, everything lines up properly. seen here:
297167

When i rotate the locking nut to facing down, the marks DO NOT line up properly, they look like they are off 1 or 1.5 degrees. seen here:
297168

Why is that, why does rotating it seem to make it read differently?

[Mike Henderson]

Looks like a defective unit to me.

Mike

[Myk Rian]

Ditto on defective. How close is it at 90º?

[Craig Behnke]

it's spot on at 90. given that the protractor body is closed on one end you can only measure 90 on one side/scale, but not the other.

[Craig Behnke]

Looks like a defective unit to me.

Mike

Mike, the crazy thing is that I thought that also, so I picked up another of the same brand (Starrett) and it has the SAME EXACT issue.

[glenn bradley]

I don't see how that can be right. How would you know which side to trust; the tick on the left or the tick on the right?

[Bill Orbine]

Nope, it ain't looking right.... I'm beginning to like all the older Starrett tools much more than what's made today. But that's me being picky!

[John Coloccia]

I think the simple solution is that the markings do not take up exactly half the circle...they take up slightly more. That would sort of imply that it's not designed to be turned more than 90 degrees. Functionally, that's probably fine, but it seems like a strange way to design it. I've used them from time to time, but I've never owned one. Seems very odd to me, but as flaky as some of Starrett's offerings have become, I don't think that they've gotten THIS bad yet, so there's a probably a good reason for it.

edit:
even at 0 degrees, it appears to be almost a half degree off on the left marking when the right marking is lined up dead nuts. Hmmmm.

[Rick Gibson]

From the picture it looks as if your locking nut is not tight. That would allow some play. Tighten the nut and see if you get the same thing. If you do a letter or email to Starret would be in order. Possibly a bad batch got out.

[Ken Fitzgerald]

If it doesn't read the same when positioned in both positions, you'd think the scale and the two reference marks are something less than 180º apart in one position and greater in the other position OR

the opening the rotating portion rides in is elliptical versus being absolutely circular.

[Craig Behnke]

From the picture it looks as if your locking nut is not tight. That would allow some play. Tighten the nut and see if you get the same thing. If you do a letter or email to Starret would be in order. Possibly a bad batch got out.

tightened the nuts, checked both protractor heads that i have (same exact model, both brand new) both show the error, one shows 1 degree , the other shows 1.5 degrees off.

[Ronald Blue]

I don't think it was ever intended to be used that way. I can't think of any reason why you would need to. I am not home so I can't check my Starrett but it is easily 75 years old as it came from my uncle who died in the early 70's and I bought all of his machinist tools. I am confident it won't be a "faulty" batch. The scale is designed to work in the range that is up to 90 degrees off zero in conjunction with the ground surface on head. I am probably not stating this well but I am certain that this will be true of any brand of protractor head. Just my .02 worth.

[Mike Henderson]

I just went into the shop to check. I have a Mitutoyo head and a Starrett head. Both can be rotated 180 degrees and they are aligned. The Starrett is somewhat old, but probably not more than 25 years. The Mitutoyo is probably of equal age. I'm just guessing on the age of both.

Mike

[Dan Hintz]

Looks like a failed stamping... maybe their die was slowly shifting out of alignment.

[John Coloccia]

The fact that even in the first picture, you can see that it's already off by almost 1/2 a degree indicates something is very wrong. You know, Starrett quality has been going into the toilet for a good number of years now. Brown and Sharpe seems to have gone to hell too. Mitutoyo is still solid as ever.

[Greg R Bradley]

Poorly made unit. You can clearly see the poorly stamped indicator lines on each side as just one example of poor quality. That type of head is never relied on for high accuracy but you should expect better than 1 degree. It isn't even close to that.

Could also be counterfeit. Did you buy it on eBay or Amazon? There seems to be a flood of counterfeit high end items lately.

[Myk Rian]

When I took lessons at the Starrett plant many years ago, one of the checks on that tool was @ the 180 degree mark. That tool is either counterfeit, or they moved production of it to China.
I would send them an email, with pictures, and ask them. There is no excuse for their tools to read like that.

[lowell holmes]

. You know, Starrett quality has been going into the toilet for a good number of years now. Brown and Sharpe seems to have gone to hell too. Mitutoyo is still solid as ever.

That's like finding out there is no Santa Claus!

[John Coloccia]

That's like finding out there is no Santa Claus!

Tell me about it. Starrett's been in decline for a good while now. I'm not saying they're junk, but there was a time you could buy any Starrett tool, and it would function perfectly right out of the box, just about every time. Those days are long gone. Brown and Sharpe quality has started declining as well. Certainly, the fit and finish of their products, at least, is in decline. Since Mitutoyo still seems to have their act together, and Starrett and B&S aren't exactly bargins, I have a hard time recommending them anymore these days. I think Starrett still make nice rules, though the markings aren't as deep as they use to be (grrrrr....I have my own reasons for liking the deep markings better), but they're nice and readily available. The combo squares still seem to be OK too, at least last I checked.

[Dave Richards]

I just checked my Brown and Sharpe protractor head. It's got the same problem although it is less than half a degree.

[Craig Behnke]

When I took lessons at the Starrett plant many years ago, one of the checks on that tool was @ the 180 degree mark. That tool is either counterfeit, or they moved production of it to China.
I would send them an email, with pictures, and ask them. There is no excuse for their tools to read like that.

Agree, I'm getting a full refund through Amazon. I'm going to grab a vintage Mitutoyo (japan made, not mexico or brazil)

[Chris Padilla]

The autumnal equinox shifted the gravitron flux of the earth's magnetic field variation. It should self-correct in a few millennia. ;)

[Bill Orbine]

That's like finding out there is no Santa Claus!

What? No Santa? I had Santa send back another type of Starrett protractor a few years ago because of similar problems like the OP stated above. Santa did just that but got frustrated with the usual poor quality replacement unit and gave up. Sent it back again (three times) and left me credit on Amazon which I never cashed in.

[Mike Henderson]

Anyone else have an older protractor head of any make? What does yours look like when you rotate it 180 degrees?

Mike

[James Baker SD]

I have a Starrett that is between 15 and 20 years old. It looks to be about 1/4 or 1/3 degree off in the normal position, dead on when upside down for what it is worth.

James

[Brian W Smith]

My B/S came from an uncle,haven't checked but it's probably post WWII....1950?Anyway,it does not have marks 180* apart,It has two marks....looking at it like a clockface,one @ 3:00....the other @12.They are as close to perfect as an un-aided eye can resolute.It's used for general purposes,we use the same co's vernier protractor as more of the,"go-to" instrument for higher precision.

[Bruce Page]

My Starrett head reads about 1/2 degree off when turned 180. My Union Tool head is dead on both ways.

[Steve Peterson]

It looks like the pivot point is not lined up with the marks. Definitely defective (or counterfeit). Returning it is a good idea. If it is an honest mistake, then hopefully they can fix the problem at the factory. If it is counterfeit, then they will just ship it to the next sucker and hope he doesn't check.

Steve

[Brad Patch]

just got a protractor head, when i look at the degree scale with the locking nut facing up, everything lines up properly. seen here:
297167

When i rotate the locking nut to facing down, the marks DO NOT line up properly, they look like they are off 1 or 1.5 degrees. seen here:
297168

Why is that, why does rotating it seem to make it read differently?

For what its worth I have an old protractor head, suspect its a Starrett, that reads dead on. I'm very disappointed to read that some feel that Starrett's quality is becoming suspect. It would be very interesting to see what Starrett had to say about this issue.

[Steve Collins]

For what its worth I have an old protractor head, suspect its a Starrett, that reads dead on. I'm very disappointed to read that some feel that Starrett's quality is becoming suspect. It would be very interesting to see what Starrett had to say about this issue.

I agree. I too would like to see what they have to say.

[Alan Bienlein]

Just checked the one at work thats about 5 years old and it reads perfect both ways. Yours is either defective or a knock off.

[paul dyar]

Checked my Starrett, and dead on both ways. Got it around 1993.

[Craig Behnke]

I sent the protractor back to Amazon for a full refund. I gave that brand and exact same model two chances and both had the issue. I have no idea if it was just defective, or a counterfeit, etc., I'm not making any claims about Starrett or slagging on them at all...I just don't have the time and desire to investigate or track that stuff down.

I found a brand new, made in Japan Mitutoyo complete combo square set (square, protractor, center finder, rule), hardened steel (IMO a slight upgrade in material vs the cast iron Starrett) for about the same price as just the cast iron Starrett protractor head. The Mitutoyo is spot on so I'm pleased with it so far. Looks and feels very high quality.

Thanks for the insight from all the comments, appreciate it.