Viceroy 280 VS Spindle Runout / Chuck runout - advice needed
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JamesH_Sussex
- Posts: 2
- Joined: Mon 27 Feb , 2012 11:11 am
- Hardware/Software: Viceroy VS280 Lathe
Microrouter Compact
Viceroy 280 VS Spindle Runout / Chuck runout - advice needed
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Last edited by JamesH_Sussex on Mon 16 Jul , 2012 22:57 pm, edited 1 time in total.
Re: Viceroy 280 VS Spindle Runout / Chuck runout - advice ne
Hi James.
Looks like the lathe has suffered an almighty trauma like a pretty heavy crash, and there's a pretty nasty dink in your spindle nose too. Your dial is showing a regular swing rather than a single kick (although it's showing a kick too) so it could be your spindle is slightly bent. You can easily find that out by putting your dial on the inside MT4 taper - that should have no runout at all.
Clearly, your results are not acceptable and the only way you are going to improve them is to remove material in order to true up the mounting. This isn't a trivial operation and quite daunting, I had to do it on my lathe though I had only a tiny high-spot on the taper and didn't have to remove metal wholesale.
The chuck relies on both the taper and the face to be held concentric. Any imperfections on the taper or face will be amplified in the workpiece so you need them as accurate as possible. It's pulled in on the taper which holds the centerline of the backplate concentric with the spindle ceterline and is pulled tight against the face of the spindle to hold the face square and between them they provide a solid mounting - both of them have to touch! If either of the surfaces aren't seated you're going to have a flexible fixing for your chuck because that short taper isn't going to give enough support for heavy machining.
The camlock taper is 7 degrees and 7.5 minutes, or 7.125 degrees, which means that for every 0.01mm you remove from the taper (measured parallel to the face), you'll need to remove 0.0813mm from the face to make the taper seat again.
If that were my machine I would approach it like this.
Your total measured runout is 0.01mm on the taper. If you machine this first your taper will be small causing the chuck to sit against the face and be loose on the taper and you have no easy way to gauge how much to take off the face to seat the chuck right. What I would do is very carefully machine 0.082mm off the face of the spindle (where the camlock holes are, not the end of the nose - that part isn't used to locate a chuck of backplate).
Now you'll find that the chuck doesn't pull back against the face. Set up your compound for cutting the taper angle by fixing your mag mount to the compound slide and running your dial gauge along the taper by winding the compound in and out - and make sure it's bang one the center height or you'll get a false reading. Keep the lathe saddle locked down tight and make sure the gibs are snug on the cross slide and compound. When you can run the dial up and down the taper with no movement you have the angle matched (within the limits of your runout and dial gauge anyway). Now touch off your tool on the taper and take tiny cuts to machine 0.01mm off it to true it up. Before you move your setup try offering up your best condition chuck/backplate to it to be sure that it pulls tight against the spindle face. Shine a light from behind or dribble some thinners onto the top and see if it wicks away.
That's the best advice I can offer. I'm certainly no expert and you might want to take further advice. It might not end-up perfect but since what you have there is next to useless you don't have a whole lot to lose. If you can get your collet chuck runout down to an amount you find acceptable and repeat it consistently you can call it a success.
Good luck and let us know how you get on.
Pete.
Looks like the lathe has suffered an almighty trauma like a pretty heavy crash, and there's a pretty nasty dink in your spindle nose too. Your dial is showing a regular swing rather than a single kick (although it's showing a kick too) so it could be your spindle is slightly bent. You can easily find that out by putting your dial on the inside MT4 taper - that should have no runout at all.
Clearly, your results are not acceptable and the only way you are going to improve them is to remove material in order to true up the mounting. This isn't a trivial operation and quite daunting, I had to do it on my lathe though I had only a tiny high-spot on the taper and didn't have to remove metal wholesale.
The chuck relies on both the taper and the face to be held concentric. Any imperfections on the taper or face will be amplified in the workpiece so you need them as accurate as possible. It's pulled in on the taper which holds the centerline of the backplate concentric with the spindle ceterline and is pulled tight against the face of the spindle to hold the face square and between them they provide a solid mounting - both of them have to touch! If either of the surfaces aren't seated you're going to have a flexible fixing for your chuck because that short taper isn't going to give enough support for heavy machining.
The camlock taper is 7 degrees and 7.5 minutes, or 7.125 degrees, which means that for every 0.01mm you remove from the taper (measured parallel to the face), you'll need to remove 0.0813mm from the face to make the taper seat again.
If that were my machine I would approach it like this.
Your total measured runout is 0.01mm on the taper. If you machine this first your taper will be small causing the chuck to sit against the face and be loose on the taper and you have no easy way to gauge how much to take off the face to seat the chuck right. What I would do is very carefully machine 0.082mm off the face of the spindle (where the camlock holes are, not the end of the nose - that part isn't used to locate a chuck of backplate).
Now you'll find that the chuck doesn't pull back against the face. Set up your compound for cutting the taper angle by fixing your mag mount to the compound slide and running your dial gauge along the taper by winding the compound in and out - and make sure it's bang one the center height or you'll get a false reading. Keep the lathe saddle locked down tight and make sure the gibs are snug on the cross slide and compound. When you can run the dial up and down the taper with no movement you have the angle matched (within the limits of your runout and dial gauge anyway). Now touch off your tool on the taper and take tiny cuts to machine 0.01mm off it to true it up. Before you move your setup try offering up your best condition chuck/backplate to it to be sure that it pulls tight against the spindle face. Shine a light from behind or dribble some thinners onto the top and see if it wicks away.
That's the best advice I can offer. I'm certainly no expert and you might want to take further advice. It might not end-up perfect but since what you have there is next to useless you don't have a whole lot to lose. If you can get your collet chuck runout down to an amount you find acceptable and repeat it consistently you can call it a success.
Good luck and let us know how you get on.
Pete.
-
JamesH_Sussex
- Posts: 2
- Joined: Mon 27 Feb , 2012 11:11 am
- Hardware/Software: Viceroy VS280 Lathe
Microrouter Compact