Machining question for lynnmor

[Pawnee]

I'm an amateur machinist.
Sometimes I need to find the center of a boss where I either don't want a mark in the center or it's too late to dimple it on the lathe.
In the attached pic I can use an edge finder to get one axis centered by using the jaw edges but in the other direction I'm not sure.
How would you do it?

Thanks,
Mike

 

[LostTrail]

What's the machine? Bridgeport (vertical) mill? When you reference using an edge finder, are you meaning one of the chuck loaded that has the spring end that 'pop' off center when spinning and bumping the piece? If so, once you find center of the jaws (Y-axis, I assume?), you could then raise the quill (Z-axis) and find center on the perpendicular (X-axis). Just a thought, not knowing what all your using.

 

[InTheWoods]

I put a 'swing-down' stop on the left side of my Kurt vise. I can easily use my edge finder to locate the back vise jaw as you describe, and them similarly locate the inside edge of the stop. Then the work goes in pushed against the stop as I tighten the vise.

 

[Sidekick]

I put the round in a collet if it's under an inch and a collet block on the bottom for clamping in the vice. Then move the vice until the square block kisses the fixed jaw then lower into the vice and clamp. Loosen the collet and replace with a drill chuck.

 

[barts]

I bought a co-ax indicator on sale, but there are a lot of ways to do this. Blondihacks goes through a bunch of them here:

She does a great job on these videos; clear, calm and focused.

 

[Pawnee]

What's the machine? Bridgeport (vertical) mill? When you reference using an edge finder, are you meaning one of the chuck loaded that has the spring end that 'pop' off center when spinning and bumping the piece? If so, once you find center of the jaws (Y-axis, I assume?), you could then raise the quill (Z-axis) and find center on the perpendicular (X-axis). Just a thought, not knowing what all your using.

It's a knee mill, Bridgeport style but Chinese.
Yes I use that kind of edge finder.
It doesn't work on a curved surface.

 

[Pawnee]

I put a 'swing-down' stop on the left side of my Kurt vise. I can easily use my edge finder to locate the back vise jaw as you describe, and them similarly locate the inside edge of the stop. Then the work goes in pushed against the stop as I tighten the vise.

I don't have a Kurt but I'm certainly jealous.
i like your stop but I can't always have the work pressed against it, the rod was just an example.

 

[Pawnee]

I put the round in a collet if it's under an inch and a collet block on the bottom for clamping in the vice. Then move the vice until the square block kisses the fixed jaw then lower into the vice and clamp. Loosen the collet and replace with a drill chuck.

I've done similar but don't have a collet block. That would work in this case but it's just an example, I don't always have a rod to find center of.

 

[Pawnee]

I bought a co-ax indicator on sale, but there are a lot of ways to do this. Blondihacks goes through a bunch of them here:

She does a great job on these videos; clear, calm and focused.

I'll watch that.
Mike

 

[Pawnee]

Thanks for the replies guys.
Wow, Blondi has come a long way, I haven't watched for quite a while. She has better equipment now and has learned a lot.

 

[lynnmor]

I would mount an indicator in the spindle and swing it in similar to what Blondi did at approximately 9:40. Of course she had way too much problem since she can't divide by two. Hopefully you have an indicator so you can tram the milling machine head in and indicate the vise.

 

[TheOldHokie]

I'm an amateur machinist.
Sometimes I need to find the center of a boss where I either don't want a mark in the center or it's too late to dimple it on the lathe.
In the attached pic I can use an edge finder to get one axis centered by using the jaw edges but in the other direction I'm not sure.
How would you do it?

Thanks,
Mike View attachment 131641

With the sàme edge finder used to index the jaw on the vise.

if you dont already have one invest in one of these - they make things a LOT easier and faster. You can get a cheap one for half the cost of that the Fowler and probably just as good.

54-575-600 Fowler Electronic Edge Finder: .200" - Call 800-469-0132 or Buy Online

Buy the FOWLER Electronic Edge Finder with .200" Cylindrical Stylus # 54-575-600 Online. Fast Nationwide Shipping or Call 800-469-0132. We Carry A Large Variety Including FOWLER Reference Gages.

www.higherprecision.com

Dan

 

[BXHoosier]

If you don’t have an indicator, put a square against the back jaw and slide it against the side of the pin and pick up the square blade with the edge finder and move over half the diameter.

 

[mikester]

google mill vice round parts for ideas

I made a mill vice clamp block with a v-groove to help locate and hold round parts

 

[barts]

Remember that if you don't have a DRO on your mill, you need to work taking the backlash into account.

 

[Bugzilla46310]

If you are wanting to find the center of a circular shape, the center finder, v shaped item, is what you need. Scribe 2 lines, where they cross is the center.

 

[Pawnee]

If you don’t have an indicator, put a square against the back jaw and slide it against the side of the pin and pick up the square blade with the edge finder and move over half the diameter.

I had not thought of that, it works well, thanks.

Also, I've got an optical/audible edge finder on order from China. I'll see how it works on a radius - Thanks Dan

 

[TheOldHokie]

I had not thought of that, it works well, thanks.

Also, I've got an optical/audible edge finder on order from China. I'll see how it works on a radius - Thanks Dan

You are welcome. If you expect to do a lot of this (I do) invest in a cheap (or high dollar) 3 jaw and clamp it to the table like this.

For initial setup you can quickly center it using a piece of round stock mounted in the spinde as shown. Set the chuck on the table, run the jaws in on the piece of stock and the chuck will self center. Then clamp it down to the table and zero your readout/dials. Its fast and GI proof. I keep that piece of 1" TGP round bar mounted in that collet chuck for just this purpose.

Using that work holding scheme you can chuck up round workpieces one after another with no further setup.

Dan

 

[Pawnee]

Well, I got the electronic edge finder, it's enormous! I knew it had a 20mm shank but didn't realize the overall size. It needs 3V to work properly, an AA fits Ok but then only the audio works, no light. I'll cobble up something with 2 button batteries. I also have to make a sleeve for the 7/8" collet or buy a 20mm.

Record shipping from China, 8 days.

 

[Sidekick]

Well, I got the electronic edge finder, it's enormous! I knew it had a 20mm shank but didn't realize the overall size. It needs 3V to work properly, an AA fits Ok but then only the audio works, no light. I'll cobble up something with 2 button batteries. I also have to make a sleeve for the 7/8" collet or buy a 20mm.

Record shipping from China, 8 days.

I tried one of them a couple years ago and it was off by .0004 when verified on a CMM. Mine was .500 diameter and took AAA batteries. They do make it easy.