DIY Centering Jig for Round Objects

[Vegaman_Dan]

Ever have trouble finding the dead center of a spindle, shaft, or round stock? Want to drill a hole in the exact center of a round item? Or even finding the center of a square object? It's easy to draw lines from corner to corner on a square object, but nothing you line up on a round end.

You need a centering jig.



I whipped this up in about 10 minutes using the laser cutter and some acrylic sheet. It's a simple design with an L shaped piece for the bottom and a right angle triangle on the top that intersects in the V notch.



Simply place the template on the surface and slide it in so the sides rest on the outside of your object. Now that top piece has a dead center axis for you to draw a line on.

Do it as many times around the perimeter as you wish, though only two lines are needed. If the lines don't meet in the middle after three, then your object isn't perfectly round.





BAM! There you go, dead center on the surface. Now you're ready to drill or mount in a lathe.

You can buy these jigs from some wood working tool sites or hobby sites like Micromark, but I wanted something in acrylic and bigger than what was available. This little tool is going to be around for a long time. I engraved some lettering to remind me of its purpose. I ended up making two since a friend found it immediately useful and I knew I'd best make one for him before mine went 'missing'.

 

[Alchymist]

I just reach in the toolbox and grab the combination square.....

 

[classicJackets]

Is the triangular bit at a different depth than the "sides" of the L? Wondering how to design that to be cut by the laser. Looks very useful.

 

[Vegaman_Dan]

I just reach in the toolbox and grab the combination square.....

The combination will do the job, but I rarely have that part attached and tend to lose it. I also have issues with not being able to see the whole surface.

I know it is reinventing the wheel- or square, but it was fun to do.

 

[Vegaman_Dan]

Is the triangular bit at a different depth than the "sides" of the L? Wondering how to design that to be cut by the laser. Looks very useful.

Two sheets of acrylic with the triangular piece glued on top of the L shaped piece below. This ensures you are resting on the top of the surface fully.

 

[rslaback]

For anyone who wants to actually make their own, you can do the same thing by joining a traditional square and a speed square.

 

[Ign]

I just reach in the toolbox and grab the combination square.....

This. Or you can buy dedicated center squares from Enco. I bought one of each size when I started school and still use them all the time.

 

[TheEquineFencer]

I just reach in the toolbox and grab the combination square.....

LOL

 

[kazlx]

I just put it in the lathe and drill

 

[Kracin]

caliper. grab the OD, divide by 2. set the caliper. now use the caliper to mark a swipe from 3 spots, where they meet is the center...

 

[brownbagg]

i really thought it was a nice idea, i did, i guess nobody else can see it

 

[Caman]

i really thought it was a nice idea, i did, i guess nobody else can see it

Oh it's a great if idea IF you have access to a laser. Not so practical if you don't.

Nice work done by the OP, well except for that corner by the "G"

 

[A_Pmech]

That's a nicely made centering tool.

Keep in mind when you use it that small changes in the roundness of an part can result in large changes in the apparent center location. I found on one piece of round stock 4" in diameter I could not locate the center closer than .060" TIR with mine. The tool was and is in perfect calibration.

 

[longlivepunk]

Nice! A good combination square set is not cheap, you had a laser, and you made something that suited your purposes! I like it. Good work.

 

[Kevin54]

That's a nicely made centering tool.

Keep in mind when you use it that small changes in the roundness of an part can result in large changes in the apparent center location. I found on one piece of round stock 4" in diameter I could not locate the center closer than .060" TIR with mine. The tool was and is in perfect calibration.

That's where you need some bluing and a good sharp scribe, and make multiple plus 6 more scribe marks. Everything has an exact center, but it may take 100 scribe marks to get there

BTW.....I like the center gage. for a plastic gage, I think it could actually be marketed as an inexpensive center finder and cater to some machinist, but mainly to DIY'ers for home use. I would probably grab that over using my Starrett as a quick reference gage which is all they are anyways. Make them in a three pack of small, medium, and large, for something like $30/3 pack.

 

[Caman]

Make them in a three pack of small, medium, and large, for something like $30/3 pack.

Make it $29.95 and you got a deal!