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Lathe turning oval not round
Posted by:
Greg Marshall
(---.cpe.sparklight.net)
Date: February 06, 2023 08:45PM
I have a section of a rod wrapper equipped with the alps upgraded chuck and the live center on the opposite end. My mandrel is 3/8 about 15 “ long. At high speed, everything looks great. No wobble at all. However , my grips are not coming out round. They are visibly OVAL! I’m using a sureform file, and, at the moment, turning burl cork. But, I have the same problem turning foam. I thought I’d checked everything. Has anybody got ideas to what can cause this phenom? Re: Lathe turning oval not round
Posted by:
Tom Kirkman
(Moderator)
Date: February 06, 2023 08:54PM
It's the tool you're using. It "floats" on the cork and EVA so it's not cutting concentric to the mandrel.
Use a lathe tool for the bulk of your sizing. That'll get it concentric and then you can shift to sandpaper for the final shape and finishing. The Surform is mostly useful for initial roughing or take down, but you are going to have to put a round nose tool or similar on there to get things concentric. [www.youtube.com] ......... Edited 1 time(s). Last edit at 02/06/2023 09:09PM by Tom Kirkman. Re: Lathe turning oval not round
Posted by:
Greg Marshall
(---.cpe.sparklight.net)
Date: February 06, 2023 08:59PM
Makes sense. Thanks, Tom Re: Lathe turning oval not round
Posted by:
John DeMartini
(---.inf6.spectrum.com)
Date: February 06, 2023 09:31PM
If the grip is not somewhat concentric to start with, you may be applying too much pressure and the file is acting like a cam lifter and it rides the surface and follows the contour.To get the grip concentric the tool should remain fixed and just touch the high spots until the entire circumference is level.
At that point one can start shaping.The best results would be using high speed and light pressure along the length of the grip. Have fun Re: Lathe turning oval not round
Posted by:
Greg Marshall
(---.cpe.sparklight.net)
Date: February 06, 2023 09:48PM
You are all spot on. I’m turning burl block where I had rounded the corners on a belt sander. Laid into it with sureform to cut it down quickly and now I can see what’s happening - sureform is following original contour. All good, it was a practice piece anyway. Thanks again. Re: Lathe turning oval not round
Posted by:
roger wilson
(---)
Date: February 07, 2023 06:32AM
Greg,
The posts are right on. In addition, you can use the surform tool, and similar tools to shape the grip - as long as you are using a tool rest. As has been pointed out, what ever it is that you are using to shape the grip must remain stationary against the spinning object. As has also been suggested - A light touch, against a fast spinning object works better than a heavy touch against a slow spinning object. Note: Depending on your setup, you may need several different adjustable tool rests. They may need to be of different lengths and even of different construction styles to do the very best job possible. For example: [www.pennstateind.com] Or, has been suggested - turning chisels: [www.pennstateind.com] Or, a different lathe: [www.pennstateind.com] Or, a different chuck: [www.pennstateind.com] ---------------------------------------------- Here is a veritable library of instructions and "how to" ideas to do various lathe turning activities with various tools. [www.pennstateind.com] Re: Lathe turning oval not round
Posted by:
roger wilson
(---)
Date: February 07, 2023 06:38AM
Perhaps that is what you really need to get your job done well:
[getbitoutdoors.com] This is a specific tool rest designed for the Alps wrapper. This tool which attaches to the Alps wrapper will give your tools and hands a rock solid base from which to do your shaping. Here is a you tube video on using the video from Batson, the supplier of the Alps wrapper: [www.youtube.com] Sorry, only registered users may post in this forum.
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