Question on billet spacing

[Cue Crazy]

I've noticed on trim biliet I make, as well as pieces I have bought sometimes that the spacing will be off in one place on the billet piece. This is somewhat puzzling to Me, and I thought maybe someone here can help me see It the right way, so I can better understand what is happening.
First off I do not see this as being caused from the centering being off or anything in that area, but am aware that can have an effect also.
I thought about this delema, and said to myself, well, maybe the diameter is just not falling even as a pie on the index points, and coming up between only 2 points creating the space between the 2 only, but the more I think about, the more it seems like the difference would be spread out between all the points, and not show up between only two. I would have thought My index points were off, but as I mentioned I have bought pieces from others that had the same thing going on. I do believe the indexing was divided correctly also, atleast in the pieces I made.

I Know this may sound dumb, and a no brainer, or maybe even hard to follow, but does anyone understand what I am refering to? Thanks Greg

 

[Sheldon]

Your indexer sucks. It's as simple as that, most likely.

 

[Cue Crazy]

Well, I have another indexer I could probably setup, and see if that Makes a difference. I bought a piece of billet someone else made, and was the same way, but don't know what indexer was used, or if the points were even divided correctly on that one to begin with.

It's really only a problem with pieces that have alot of slots, or are wider. Maybe I need to experiement and see if I can find a specific point on the index that Is off. possibly work around It If so. I know the piece of billet is locked in good also, so don't think It's slipping, and causing it.

Am I correct in believing that If the points are divided evenly, as they should be, that any difference in diameters would be automatically spread out over the entire range of indexing points? Thanks Greg

 

[Arnot Wadsworth]

Your indexer sucks. It's as simple as that, most likely.

I agree with Sheldon. It is also possible that you are holding the work between centers and it is slipping. Good luck.

 

[Sheldon]

Am I correct in believing that If the points are divided evenly, as they should be, that any difference in diameters would be automatically spread out over the entire range of indexing points? Thanks Greg

Yes, you are correct.

 

[Cue Crazy]

Thanks guys,

I am pretty sure the piece is not slipping on Me, as that is what I first suspected, but anythings possible. I am going to double check My indexing when I make some more up here, and look for movement, to be sure I have the piece locked down really good, just to be safe.
The pieces are not that bad, just would not want to use it in anything I have alot of time in, or costly, maybe on some not so sneaky petes to spice them up alittle, but that's about it. If I cut them thin, you have to really look to notice, and they still look good. Thanks again, atleast I will know I'm looking in the correct area to locate the problem. Greg

 

[cueman]

Those 24 holes in your indexing are drilled with a CNC machine. I don't think it is the indexing spacing.

 

[Cue Crazy]

I have several different Index units Chris, I'm trying to set up an independent unit. That machine stays tied up just about all the time, so can't keep it tied up with this too often, and really need more of them setup Like you do for various ops. As You know I am setting the copier up independent for the same reason. I also have plans for a independent taper unit which I have some parts for.

The indexer Is a import, so It's even that, the plate shifted, or the way I'm mounting the billet. probably something I am setting up wrong, but seemed locked in good when i check for play in it. I have a three jaw chuck with 5c adapter could be a centering issue that needs indicated. I'll figure it out. I just recently bought a piece from another that was the same way, and it seemed strange. Guess it was seconds. Could of made that Myself

Speeking of index units I even have a small one that mounts to a t milling attatchment. Think It was a watchmakers unit. It's a cool little setup, but so small have'nt found a use yet. It only accepts around 1/4-5/16 and under arbors.

I need one to fit that bedway for My other setup, the standard height would work, My tailstock has no riser block. Know where I can get one by any chance?

I'll try a piece in the csd to see how It comes out. What's the best way to mount the blank In It? The spur drive, cut a tenon to mount in the chuck, or bore the piece, and make a tenon to fit it tight? I might just spend a day & night cutting billet on it next break I get in use. Thanks Greg

 

[hadjcues]

Greg,

I normally drill/bore the billet and stick a dowel in it. Long enough to do the operation I need. when done, drill and bore the billet to the size you need.

Btw, misallignment of centers could also cause uneven spacing when you do cut the rings to size. Also a thing to look out for is the cutting bit should also be centered properly or else the slots would be cut up in an angle and misallignment could happen when trimming the billet down to size. Also make sure the slots are cut at a constant depth.

Hadj

 

[Cue Crazy]

Greg,

I normally drill/bore the billet and stick a dowel in it. Long enough to do the operation I need. when done, drill and bore the billet to the size you need.

Btw, misallignment of centers could also cause uneven spacing when you do cut the rings to size. Also a thing to look out for is the cutting bit should also be centered properly or else the slots would be cut up in an angle and misallignment could happen when trimming the billet down to size. Also make sure the slots are cut at a constant depth.

Hadj

Thanks,

Think I am going to be sure My centers are straight by boring the piece alittle smaller then the final bore dia, and go with the stuffed tenon.

On the cutting bit angle, I'm with you on that, and been there, so know exactly how to tell. The end of the piece usually tells the tale on that. the ends looked like the angle is fine, just have one space too wide, and it's spread out evenly throughout the lenth of the piece. Does'nt always happen, so got a feeling the blank is slipping somehow, or either the indexing plate did. I'm going to look at the billet really close again, and see what that tells Me. Sure I'll figure it out eventually. Greg

 

[Jon]

The easiest way (for me) to center up the cutting bit is to dial the cutter (stationary) up next to the work piece. Make sure you know the exact dimensions of the cutter and work peice. Then dial it in slow until it touches (can't see light) and then make sure the cutter clears the work piece, and dial towards the center, half the diameter of the work piece, and then half the width of the cutter.

Works for me.

I do it on a Hardinge Horizontal Mill, and a Hardinge 5C indexer (we've got three of 'em , two 24 space, and one 20 space.)

The import indexer now i holding place for dust...
At least it has an important job now

 

[Cue Crazy]

I center using the center line also. Thought about making a parallel block of some type to help square the bit up, but only problem is that different dia cutting bits would not all lay on the block flush, as there would be a space with a smaller dia bit, and would still have to slightly eyeball It. I guess standard parallels or shims could be added to make up the space though.

Me too on the important job for the index , Mine is sitting on My bench holding up wasted paper towels and wet paper that's piled half way to the ceiling half the time so it has a important place getting in My way LOL. I recently leveled the mountain, when I cleaned up alittle better, and found it down in there with that knarly looking jaw on it, so got Me thinking about trying it again, and setting It back up. I am just looking for punishment on that Huh. maybe I should just use a collet on it instead.

It's better then the way I made the first piece I ever tried. a drill press with cross slide and clamp on top to hold the work piece. unclamp, turn to line up the marks, and clamp It back down , indexing was marked in pencil using the index on my old wood lathe, and had to be lined up by hand in the drill press. those were desperate measures in those days.

You showed me your billet, really nice looking stuff, when you going to sell Me some to use until I get my ---- straight

If you don't mind Me asking, what rpm you running that mill at anyway, or do you have a router strapped to it somehow? I do envy You with all that heavy iron at your disposal. must be a good life when you can get up in the morning, and put those to good use.

Thanks Man, Greg

 

[Jon]

I center using the center line also. Thought about making a parallel block of some type to help square the bit up, but only problem is that different dia cutting bits would not all lay on the block flush, as there would be a space with a smaller dia bit, and would still have to slightly eyeball It. I guess standard parallels or shims could be added to make up the space though.

Me too on the important job for the index , Mine is sitting on My bench holding up wasted paper towels and wet paper that's piled half way to the ceiling half the time so it has a important place getting in My way LOL. I recently leveled the mountain, when I cleaned up alittle better, and found it down in there with that knarly looking jaw on it, so got Me thinking about trying it again, and setting It back up. I am just looking for punishment on that Huh. maybe I should just use a collet on it instead.

It's better then the way I made the first piece I ever tried. a drill press with cross slide and clamp on top to hold the work piece. unclamp, turn to line up the marks, and clamp It back down , indexing was marked in pencil using the index on my old wood lathe, and had to be lined up by hand in the drill press. those were desperate measures in those days.

You showed me your billet, really nice looking stuff, when you going to sell Me some to use until I get my ---- straight

If you don't mind Me asking, what rpm you running that mill at anyway, or do you have a router strapped to it somehow? I do envy You with all that heavy iron at your disposal. must be a good life when you can get up in the morning, and put those to good use.

Thanks Man, Greg

As far as the RPM on the mill, i would have to go look.
All i know is that i change the belts for the fastest possible speed.
The only problem i have with the router set up, is that it is harder to make sure that your cutter is either parallel or perpendicular (depending on the mount and cutter.)
So i'll stick with the mill.