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Posted: 6/28/2009 2:01:58 AM EDT
| What advantage, if any, is using a floating pilot reamer instead of a solid pilot reamer? |
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As in a finish chamber reamer?
Are you using a lathe or are you going to hand turn the reamer? A floating reamer will work best on a CNC lathe as it allows the tailstock or toolholder to fully center before it begins the feed, you have to program dwell time and I can't remember the exact code parameter because I rarely work the CNC lathes. If you are using a standard feed lathe or are hand turning, you will want the regular reamer. Remember to let the lathe come to a complete stop before you remove the reamer from the hole. Same thing if you are hand turning, don't turn the reamer as you withdraw it, bring it straight back. This will prevent any chip buildup from scoring the side walls of the hole as the reamer is withdrawn.HTH |
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As in a finish chamber reamer? Are you using a lathe or are you going to hand turn the reamer? A floating reamer will work best on a CNC lathe as it allows the tailstock or toolholder to fully center before it begins the feed, you have to program dwell time and I can't remember the exact code parameter because I rarely work the CNC lathes. If you are using a standard feed lathe or are hand turning, you will want the regular reamer. Remember to let the lathe come to a complete stop before you remove the reamer from the hole. Same thing if you are hand turning, don't turn the reamer as you withdraw it, bring it straight back. This will prevent any chip buildup from scoring the side walls of the hole as the reamer is withdrawn.HTH I have access to a standard engine lathe. At the moment, my plan it to use it for this project. I have 4 barrels to ream. Two are short chambered in 30-06 and I want to finish ream them. Two are currently chambered for 30-06 and I want to convert them to 308. At present, I plan to cut about 3/4" off of the chamber end and then cut a 308 chamber. How many RPMs should I run ? |
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How many RPMs should I run ? For tool steel reamers use the slowest speed you lathe can give you. I start at 58 rpm and will go to about 120 rpm, dependent on the feel while reaming. I have been told to run carbide chamber reamers no slower then 300 rpm, I have never used one. Floating pilot reamer allows you to change pilots, for best possible fit to the bore of the barrel you are chambering. PTG offers pilots for their reamers in 0.0002" incriments. With the fixed pilot reamer you are stuck with what ever pilot was ground on the reamer. I have had barrels where the fixed pilot would not start in the bore. Additionally barrels with non standard rifling patterns can have different specs for the bores. For example a 30 cal poly bore will be .301 versus the nominal .300, and a typical fixed pilot reamer for a 30 cal cartridge will be at most 0.299". |
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How many RPMs should I run ? For tool steel reamers use the slowest speed you lathe can give you. I start at 58 rpm and will go to about 120 rpm, dependent on the feel while reaming. I have been told to run carbide chamber reamers no slower then 300 rpm, I have never used one. Floating pilot reamer allows you to change pilots, for best possible fit to the bore of the barrel you are chambering. PTG offers pilots for their reamers in 0.0002" incriments. With the fixed pilot reamer you are stuck with what ever pilot was ground on the reamer. I have had barrels where the fixed pilot would not start in the bore. Additionally barrels with non standard rifling patterns can have different specs for the bores. For example a 30 cal poly bore will be .301 versus the nominal .300, and a typical fixed pilot reamer for a 30 cal cartridge will be at most 0.299". Excellent.Thank you sir. Now I can make an informed decision. The lathe that I use has 45RPM as the lowest setting. The rental co web site states that the reamers are HSS tool steel. |
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That is about as good an assessment as you can get right there.
Remember, the larger the diameter of the reamer, the slower you need to set your speed and feed. Run the rougher if you are using one at the slowest speed that creates a clean cut and run the finisher at roughly double the speed and feed as the rougher. Work no more than .015" at a time with the rougher and .005" at a time with the finisher and clean the reamers often. I wouldn't look at this type of a job as a production line operation so go slow. PS I apologize if it looked like I was cutting you off, I had some real world issues I had to deal with. 
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Who are you renting from? I need a .50 BMG. http://www.reamerrentals.com/SearchResults.asp?Cat=309 |
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