Need A Centering Square: What Do You Guys Recommend?

CluelessNewB said:
As a compromise between Starrett and the stuff from China check out Products Engineering , made in USA

Here is a link to one on the Harry Epstein site, poke around in the Machinists tools for other selections.

https://www.harryepstein.com/index.php/12-4-pc-combination-square-16r-usa.html

Personally I would avoid any with heads made of aluminum like you find at Home Cheapo and Horror Fright, even for home use they don't hold up.
Click to expand...

I have that PEC combo square you link to. I also purchased it from Harry j's about 3 years ago. Very good quality. Almost impossible to find the cosmetic defect. Very good buy if you don't want to spring for the Starrett version.

Roy
 
My interpretation of your project would be to use layout dye on the end, use a small center drill to establish a center in the work in the lathe chuck; use dividers to establish the circle diameter; also with the dividers establish a line across the center hole and establish two points on the desired circle diameter. From there I think you would be able establish another line to intersect the circle at 90` to the original line. Note I never took Geometry is HS but am reasonably sure these techniques are possible.
With respect to a center guide I like the product recommended by CluelessNewB and if I didn't already have one that's where I would go. No affiliation to PEC or CluelessNewB.
 
Thanks for all your responses. I decided to place an eBay bid on a older Union Tool 18" rule with a square and centering head. This will provide
interchangeable parts with an old 12" Union square that was my Dad's and that I've had for years. The starting bid was less than
what I would pay for the simple fixed square in the pic above so if I win it I'll be way ahead.
 
Nogoingback said:
Thanks for all your responses. I decided to place an eBay bid on a older Union Tool 18" rule with a square and centering head. This will provide
interchangeable parts with an old 12" Union square that was my Dad's and that I've had for years. The starting bid was less than
what I would pay for the simple fixed square in the pic above so if I win it I'll be way ahead.
Click to expand...
Union Tool Co., Orange, MA, was in business from 1908 to 1975. They made rules, squares, gauges, etc. Nice tools. Take good care of your square and cherish it along with the memory that it came from your Dad. Tools like that are the most special ones we can have. I have a few Union tools myself, a couple of them from my Dad. Tools like that are kept in a special drawer, and soon will be in a Wedell & Boers wooden tool box from the 1920's, after I get it rehabbed some.
Edit: I am getting off topic again, need to get back to the thread...
 
You're absolutely right Bob, it is a nice tool, and special because I associate it with my Dad. I use it frequently, and then put it
away carefully.
 
a centering square will only get you close to round piece of stock. Like Bob Korves wrote above, out of round and the lines won't intersect.
I had an iGaging centering square but sold it for this reason. My Starrett center square attachment worked just as well, or got me the same results with out of round stock. Better to start with a part that is turned using a DI on a lathe first.
 
Nogoingback said:
The task I'm working on now is to turn a 4" diameter aluminum round down to 92 mm. I've faced it off on both sides in a 4 jaw
chuck already, but need to mark it with lines at 90 degrees to one another so that I can drill for 4 bolt holes. It will be mounted
on a face plate and the OD turned to size. I'm not looking for the center, I'm trying to mark it for the bolt circle which only has to
be accurate enough to mount on the face plate. So high accuracy isn't important for this job, but as long as I'm buying one I thought
I'd ask and get something decent.
Click to expand...


When in the 4 jaw chuck . mark it at each jaw. you will have 4 marks 90deg apart.

That said never pass up an opportunity to buy new tools. I would watch eBay and get a good combination square set.
 
EmilioG said:
a centering square will only get you close to round piece of stock. Like Bob Korves wrote above, out of round and the lines won't intersect.
I had an iGaging centering square but sold it for this reason. My Starrett center square attachment worked just as well, or got me the same results with out of round stock. Better to start with a part that is turned using a DI on a lathe first.
Click to expand...

I'm aware that that's a more accurate way to do it, but in this case I plan on getting it close, bolting it up, and then turning the OD. I've got lots of
material to work with: it's a 4 inch disc, about 7/8" thick, but it will be turned down to about 3.60".
 
"That said never pass up an opportunity to buy new tools. I would watch eBay and get a good combination square set."

Yup, that's the plan.
 
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