Some finds - center heads with rules

[Alfred Kraemer]

I bought these three items a while ago at a local flea market for $5. I had been looking for a small center head with a small rule. Well, I found two and then added an older Crescent wrench. The wrench was pretty clean, but the two center heads were not.
The bigger center head with the longer rule baffles me a little. Is it a Starrett? The rule is marked but I only see an 1880 patent date on it. I know that that can precede the date when it was made by decades. The knurled nut has grooves that run at an angle and the rule is as thick as a 12 inch Starrett rule. Anyway, it is straight and perfectly usable, although I had to clean up the rule to see anything.
The smaller Lufkin - I think - was only covered in paint and cleaned up well.

If anyone knows more about the Starrett (?) center head, please let me know.


Alfred

[Bruce Page]

It's hard to say for sure. It looks like a Starrett nut but mine does not have the angled knurl. Good haul anyway.

[Jim Davis]

The Starret? rule is graduated in a way I have not seen on one of that brand, but that proves nothing. I have not seen a Starret marked in 32nds on both edges of the same face. My 1970s Starret center head has a knob that looks like the one above, but has straight knurling.

It seems to me that all Starret scales would have the L.S. Starret name on them. Sometimes, that name is in very small letters and kind of faint. Maybe it got lost in the cleanup?

Guess I'm not much help.

[Mel Fulks]

Even if it's not LSS brand its a good find. I've used and seen others using those in woodworking. A warning: machinists most often use those on things small enough to fit inside the triangle. When you use them with the ENDS of the legs contacting large
circles most are not accurate, so you need to make a mark ,then flip it over to change leg position ,make another line, then
bisect for true center. Seen some goofs made by those nor realizing that. Some opt to grind a little off one leg to improve accuracy on larger items.

[Jim Koepke]

When you use them with the ENDS of the legs contacting large circles most are not accurate, so you need to make a mark, then flip it over to change leg position, make another line, then bisect for true center.

My tendency is to make a mark, spin the piece being marked, mark again, spin again, repeat until there are anywhere from four to six lines on the piece. There is often just a bright spot in the center inside all the markings.

jtk

[Mel Fulks]

Yeah, Jim's method is better, thanks for clarification.

[lowell holmes]

I have the Starrett center finder with Starrett rule.

If the piece is truly round, three marks will meet in the exact center.

If they don't meet, there may be issues.

[Mel Fulks]

Where Ive seen the goofs has been on large radius stuff like bar rails ; not being a whole circle the multi -mark won't work
and reverting to the bisect two lines is necessary. When you warn someone who is young they always say
"but this is a Starrette,it's made to be accurate!" Then "thank you,thank you!! Didn't know that!"

[Jim Koepke]

When you warn someone who is young they always say
"but this is a Starrette,it's made to be accurate!" Then "thank you,thank you!! Didn't know that!"

I would then ask them if the piece being marked is also a Starrett.

Just because the tool is accurate, the item being worked on can be bordering on elliptical instead of a perfect example of round.

jtk

[Alfred Kraemer]

I would then ask them if the piece being marked is also a Starrett.

Just because the tool is accurate, the item being worked on can be bordering on elliptical instead of a perfect example of round.

jtk

Thanks for the responses and suggestions. Both center heads are good. I used a 5 inch circle, and drew 5 lines through the center with the centerhead aligned at different places on the circle perim all of the lines met at the same point. I used a mech pencil not a scriber, but that precise enough for my purposes.
I also found a pic by googling 'Starrett patent date 1880' of what looks like the center head. It seems it is a bit older than I thought, probably closer to the patent date than I thought too. The picture reference mentions that it is from the practical machinist web site.

http://i49.photobucket.com/albums/f2...S-Square-5.jpg

Maybe I should have dug around a little more in the box at the flea market to look for the square head. I do think the rule and the center head belong together. My other, old -but not that old- Starrett square rule has a round/concave center groove bottom, this one had a flat bottom center groove.

Alfred

[Bruce Page]

http://i49.photobucket.com/albums/f2...S-Square-5.jpg
Alfred

Thanks for the link. There are some fascinating antique tools shown, many that I have never seen before.