Help with a hole to be perfectly vertical in a mill

[Dhector]

Attempting to mill keyway in crankshaft that originally came with dowel pins. Question is how to be sure the hole is perfectly centered and vertical in the mill vise. The owner wants to put keyways in the crank(outlined in red) so the gear is held with more surface area to keep it from shearing the dowel pins. This crank is junk and a "test" crank to see how it goes. I have some indicators and can level it horizontally with ease, but curious how to be certain the centerline of the dowel is perfectly vertical. Hope that makes sense. Thanks.

 

[mickri]

Use an edge finder to find the center of the journal. There are lots of videos on how to do this. Do a search online.

 

[682bear]

Find the exact center of the journal on the crankshaft and set that as zero. Next, find the center of the dowel pin hole... if the hole is vertical, the center of the hole will be at the same zero as the center of the journal.

This is assuming, of course, that the pin holes were originally drilled in the center of the journal.

Or, put a longer, straight pin in the hole and indicate it vertically... a guage pin should work.

-Bear

 

[Ed ke6bnl]

I am just a hobbier but I would use you edge finder to find center between the jaws then flip that edge finder over so the point is down and get the shaft so it is centered on the with the pointer on the edge finder. or use a dowel pin to go in the hole of the shaft. just my thought.

 

[Dhector]

Thanks for the replies. Center of jaws I did, but the vertical was my concern. I thought about using a dowel or gauge pin, but I dont have any. Would have to make one but I may do that and see how it goes. Thanks again.

 

[compact8]

Find the center between the jaws, find the center of the hole, rotate the parts until the two centers coincide ?

 

[tq60]

Does the pin align with something else?

If it aligns with a lobe then place DI in spindle and rotate crank until dead center.

Sent from my SM-G781V using Tapatalk

 

[rwm]

You posted a weird video format! (.hiec)

 

[Chewy]

I would use a DTI not an edge finder. Make or use a gauge pin and install. Then using a DTI, swing it around the base of the pin and get exact center, Then raise the DTI up until almost the top and repeat, keep adjusting until no change. That will take care of any off vertical you may have. If you don't have a DTI you can get them for around $17 at Amazon. The normal way to do this is with an Indicol. Watch Jo Pi videos. You can get knockoffs on Ebay for around $15. I also use a homemade one for quick tramming and small stuff lie this.

Take a piece of 3" long 1" diameter 6061. Turn down about 2" to a common size, 3/8 or 1/2". On the remaining 1" drill a small hole to fit DTI peg in dead center and offset about 5/16". Cross drill for setscrew. You can now quickly check any pin or hole from about 0 to around 1-1/8". It takes less adjustment then an Indicol. You will need to use mirror for back side view. I can post a picture if you want to see it. I have a DTI in it permanently.

 

[Dhector]

Does the pin align with something else?

If it aligns with a lobe then place DI in spindle and rotate crank until dead center.

Sent from my SM-G781V using Tapatalk

The pin is actually for a gear to slide on and be timed and/or held from spinning. Might be a harmonic balancer held on as well, Im not sure, they handed me the crank and told me what the plan was! I didnt tear it apart. See pic.

You posted a weird video format! (.hiec)

I thin that has to do with the phone I just got. I had to download a file from microsoft just to view pics. Assuming the pics worked for all of you?

I would use a DTI not an edge finder. Make or use a gauge pin and install. Then using a DTI, swing it around the base of the pin and get exact center, Then raise the DTI up until almost the top and repeat, keep adjusting until no change. That will take care of any off vertical you may have. If you don't have a DTI you can get them for around $17 at Amazon. The normal way to do this is with an Indicol. Watch Jo Pi videos. You can get knockoffs on Ebay for around $15. I also use a homemade one for quick tramming and small stuff lie this.

Take a piece of 3" long 1" diameter 6061. Turn down about 2" to a common size, 3/8 or 1/2". On the remaining 1" drill a small hole to fit DTI peg in dead center and offset about 5/16". Cross drill for setscrew. You can now quickly check any pin or hole from about 0 to around 1-1/8". It takes less adjustment then an Indicol. You will need to use mirror for back side view. I can post a picture if you want to see it. I have a DTI in it permanently.

Im gong to have to look up what DTI is and was planning on making a pin to indicate from.