[CadRhino]

Has anyone used a hole in the vertical side of a part to locate an axis (X axis)?
If so, what type of indicator did you use?
I don't have a interapid indicator on a sweeping arm (yet) but it looks that might be able to work if one has the indicator horizontal.
I don't think I can use my probe since it only points down.
Thanks so much,
Nathan

[Hirudin]

Can you stick something like a gauge pin into the hole?

Maybe I'm missing something obvious, but I don't understand what you're trying to do.

[mountaindew]

I think he is locating his part based on a hole.
If so, I use a mitutoyo center / edge finder. (search amazon) Same as the single edge finder only it has point and I use it to find a center of a small hole using the dro.
Hope this helps.

[CadRhino]

Hi Hirudin,
I am attaching a photo of the part. The hole on the vertical leg I want to center for the drilling and countersinking operation on the flat leg of the angle. The holes I will be making need to indicate off of this hole.
I have a probe and several of the mitutoyo type center / edge finders but do not have a way to indicate the axis off of this opening since it is enclosed in a vertical plane and not horizontal. This is why I was thinking that an interapid indicator on a sweeping arm might be able to work if one has the indicator horizontal.
Hope this makes some sense.
Thanks for your reply,
Nathan

[nitewatchman]

I run into the same problem when cutting the Fire Control Pocket on an AR-15 Lower Receiver. I put a dowel pin through the Pivot Pin Hole. I find both sides of the dowel pin with an edge finder and split the difference. This becomes X-Zero. I then do the same thing with the Takedown Pin Hole as a check. The center of it should be found at X6.375. If I find it there we are good to go. If not, I go through the setup again since I know that it was there when I put the two holes in from the side.

The receiver hole is deep enough to hold the dowel pin snugly, your hole is a little shallow. You may have to turn a "Blind Rivet" style dowel so that the head can align the pin along the centerline of the hole.

nitewatchman

[philbur]

The method will depend on the precision required. More often than not the eyeball method is good enough for fabricated parts.

A rod with a diameter the same as the hole in the spindle and positioned across the hole at the back, then move and eyeball until the rod is across the centre of the hole as seen from the front. Should be good enough for + or minus a few thou.

Phil

[Hirudin]

Is that the thing that you have 40 of? How accurate do you want/need them to be? If it doesn't need to be dead-on I would guess you could just indicate off one of the corners. To do 40 of something like that I might indicate to the fixed jaw of my vise and then line the edge of the angle bracket with the edge of the jaw. That way you could quickly slap each one down and get it going. If you have 20 "lefts" and 20 "rights" I would indicate off the left and right sides of the vise jaw, respectively.

IF you want more accuracy I would probably do a second operation to correct/expand the initial hole. That is to say I would use an end mill to increase the diameter of the initial hole from 3/8" to, say, 7/16". That way the hole would be accurately sized and, more importantly, accurately located. For even more accuracy you could drill/ream/bore out the hole. If you do this second operation make sure to locate off the same corner.

If you really want to go crazy you could recut part or all of the profile of the bracket as well.

One last thing: if you have a height gauge you could use it to quickly check how much variance there is in the parts as they are now. Place the angle down on your surface and line the scribe of the height gauge up with the bottom of the hole then use that measurement to compare the rest of the brackets. Then turn the brackets onto the edge you plan to indicate from and repeat the process. Hopefully the holes are already "good enough" for what you're doing.

[Jabs1542]

You could flip the part, with the hole now horizontal, and measure the center of the hole relative to one of the edges (the long edge would be easiest). Then flip the part back to vertical, indicate the edge you had referenced and use a G1 on the MDI to bring you back to the measurement you obtained earlier.

If you are making 40 of these you could use a similar technique with a work stop. Flip it so the hole is horizontal, secure the long edge (right at the bend) to the work stop, find the center of the hole, then flip the part and secure the corner at the bend against the work stop. From that point just reference every part against the work stop.

This assumes you don't need aerospace tolerances

[kstrauss]

What are the accuracy requirements? If the eyeball is not accurate enough, I would use a tooling ball. I don't see a mention of the diameter of the hole. You need to get a ball with a stalk that that is a close fit to the hole but you could make a sleeve if the hole is too large. Some balls come threaded for a tiny "drawbar" to secure the ball in the hole. With a ball and DTI in the spindle you could quickly get a very accurate location for the hole.

[al010964]

Hi Nathan,

I ran into the same problem when I was making a mount for an rc gas plane.

I solved the problem in the same manner that the nitewatchman described, quick and easy.

Cheers,
.adrian

[Peter Neill]

Stick a dowel pin in the hole and use one of these. Had it for years and it's a very useful little tool, accurate to within a couple of thou'

Off-centre:



Move table a bit, then it's on-centre:

[CadRhino]

Unbeknown to me, the folks who did the waterjet cutting on these parts ground the ends so indicating off of the ends will not be equal to each other. This is why the center hole will be most important.
I could try it since the part tolerances are +/- 1/32". They didn't take off more than a couple thou.
I like Nightwatchman's approach too. I could turn a part on the lathe for that.
This Haimer Centro bent tip if for horizontal hole indicating but it looks like it might do the job too - 33027 - 5mm Bent Tip for Haimer CENTRO
I have too many other things I need to buy before getting a nice Haimer.
Thanks for everyone's feedback.
Proof that machining is art plus technique.
-Nathan

[CadRhino]

Paul,
That is sweet. I could use that when I start using my 4th axis setup.
I will Google it to see where I can find one.
Thanks,
Nathan

Stick a dowel pin in the hole and use one of these. Had it for years and it's a very useful little tool, accurate to within a couple of thou'

Off-centre:



Move table a bit, then it's on-centre:

[Peter Neill]

Just Google for round bar centre-finder and that get one

[Jabs1542]

Nathan,

Please post your success and source if you find one of these, this looks way too handy to not have.

Jay

[kstrauss]

Enco #328-004 for $16.42 or Little Machine Shop #2747 for $13.50 or... The ones that I've seen are somewhat sloppily made so I doubt that you'll consistently get within "a couple of thou'".

[CadRhino]

I just looked at the Grizzly one for $3.50 an was not impressed. I am now looking at the SPI one at Enco - Enco - Guaranteed Lowest Prices on Machinery, Tools and Shop Supplies
It looks better but trying to determine its tolerances first.
-Nathan

Nathan,

Please post your success and source if you find one of these, this looks way too handy to not have.

Jay

[mike sr1]

I have one and use it to get a ballpark center on round or rectangle bar if it will fit over the stock.

[Peter Neill]

Enco #328-004 for $16.42 or Little Machine Shop #2747 for $13.50 or... The ones that I've seen are somewhat sloppily made so I doubt that you'll consistently get within "a couple of thou'".

Yeah, quite true I suppose, YMMV.
I've been lucky with mine and it's been pretty spot on & repeatable, and I do use an opti-visor magnifier to check the marks alignment and it's never been more than that amount off centre, but they're not really a super-precision instrument.
But for a hole through a bar that's usually drilled to take a pin or tapped to take a grub-screw, or even a keyway, you can't really beat them.

[CadRhino]

I just ordered the SPI one.
I watched the Tormach video on setting up a 4th axis with a 4-jaw chuck (which I have) and it looked slow to me.
If the SPI gets me 90 percent there quickly then I will use an inter rapid for the rest.
I will post my experience.
Thanks for all the feedback.
Nathan

Yeah, quite true I suppose, YMMV.
I've been lucky with mine and it's been pretty spot on & repeatable, and I do use an opti-visor magnifier to check the marks alignment and it's never been more than that amount off centre, but they're not really a super-precision instrument.
But for a hole through a bar that's usually drilled to take a pin or tapped to take a grub-screw, or even a keyway, you can't really beat them.