Want to verify TDC spot on my harmonic balancer to make sure my timing is accurate.
Reading a tutorial by Ebooger, but I just can't seem to follow the method.
Technique uses a homemade tool with old spark plug and bolt.

Are these the correct steps?

1) Rotate engine CW till #1 piston reaches highest point and then does down 1/4"
2) Thread in homemade positive stop tool until bolt touches piston.
3) Rotate engine CCW until it won't move (How can it move if you just threaded bolt on piston?)
4) Mark damper at TDC mark
5) Rotate engine CW until it stops (Won't is just keep going down, went past TDC in Step 1?)
6) Make 2nd mark on damper at TDC mark
7) 1/2 way point between marks is TDC

What am I missing, haven't tried it yet, but don't see how this works.

(1) turn the dampener till the slit is about an inch or slightly more than a inch to the left (BTDC) of the zero (TDC) mark on the tab (2) thread in the tool till it makes contact. (3) With a sharpie make a mark on the dampener at the zero mark on the tab. (4) hand turn the crank CCW till it makes contact again & make another sharpie mark on the dampener at the zero (TDC) mark on the timing tab same as before. (5) remove the tool. (6) With a strip of paper (a tape ain't flexible enough) measure the distance between your 2 marks & if your dampener TDC slit is halfway between that measured distance you are dead on. If not, then make a new mark with white paint on the dampener halfway between your 2 dampener measured marks & use that instead of the original TDC slit. With TDC confirmed you can make new advance marks. 0.0632683" around the circumference is (1) degrees so you can make your new timing marks with your calculator & some easy math & 4 of em (10-15-20 & your total is plenty). For example 2&7/32" is 35 degrees (total) EDIT Make new advance marks on the dampener to the right (clockwise) of your new TDC mark with you facing the eng

You turn the crank in one direction , set the stop then you turn the crank in the OPPOSITE DIRECTION till the piston comes up to the stop again. do this slooooowly as you approach the top again.

You can NOT rotate it THROUGH the stop obviously....

Well, you could if you were The Hulk!

R.

Appreciate the responses, I must be dense, still not "seeing" it.

Given the stop tool is fixed, threaded stock through a spark plug.
So there is no up and down give.

If I position the stop on the piston (thread the bolt all the way down till it touches piston) when the piston is not all the way up (TDC) how can the piston go up further?

Because the part I haven't seen anyone mention is once you have the two locations there the crank locks against the dead stop now you measure the distance between those two points split it & thats where you put a true TDC mark...