Hi guys,
I realize this is mostly a powder-burning, firearm section of the forum & my question pertains to an airgun build I’m currently doing, but the parameters are basically the same (other than AG barrel is softer steel than a PB barrel)
Anyways, after a lot of research on the topic I’m now in the process of making my very first chamber reamer (piloted) for a .177 pellet-shooter project I’m currently working on & was wondering if any of you fellas “in-the-know” could clear up a few details for me that I either missed in my search or info wasn’t provided?
1) Do you turn your reamers to the exact final, finished size needed, or do you make it .0005” (+/-) smaller to allow for bore lapping/polishing after cutting with reamer? BTW, barrel will be mounted in 4-jaw chuck, appropriate pin gauge in bore & indicated with DTI to be perfectly centered so chuck runout *shouldn’t* be a factor…
2) Should (solid) pilot be sized to just kiss top of lands (i.e-exact fit with bore minor diameter) or would I also make it slightly smaller (.0005”- .001“) to prevent galling of lands? I ‘may’ be able to make it a live pilot w/brass bushing replacing solid pilot if need be, but .177 reamer is already pretty tiny without drilling/tapping end for pilot sleeve.
3) Now this might be a silly question, but I’m new at this & need/want to learn sometime anyways, soooo - how many flutes/cutting edges? Have read that you generally don’t want all your cutting edges to coincide with rifling lands to prevent “train-tracking” (“bump, bump, bump” while reaming). My barrel has 12 lands/grooves, so should I make the reamer with 5 flutes (1 flute always in contact with land), or could I get away with 3 or 6 flutes? I don’t have a spin index so will be using a hex collet block in vice to index flutes, hence the 3 or 6 flute reference. 5 flutes @ 72* apart might be difficult for me to accomplish accurately without a spin index…
My apologies for all the noob questions, just want to make sure I’m going at this the right way & not fubar a $100 barrel!
Thank you very much for your time & any insight you can offer…
Todd
I realize this is mostly a powder-burning, firearm section of the forum & my question pertains to an airgun build I’m currently doing, but the parameters are basically the same (other than AG barrel is softer steel than a PB barrel)
Anyways, after a lot of research on the topic I’m now in the process of making my very first chamber reamer (piloted) for a .177 pellet-shooter project I’m currently working on & was wondering if any of you fellas “in-the-know” could clear up a few details for me that I either missed in my search or info wasn’t provided?
1) Do you turn your reamers to the exact final, finished size needed, or do you make it .0005” (+/-) smaller to allow for bore lapping/polishing after cutting with reamer? BTW, barrel will be mounted in 4-jaw chuck, appropriate pin gauge in bore & indicated with DTI to be perfectly centered so chuck runout *shouldn’t* be a factor…
2) Should (solid) pilot be sized to just kiss top of lands (i.e-exact fit with bore minor diameter) or would I also make it slightly smaller (.0005”- .001“) to prevent galling of lands? I ‘may’ be able to make it a live pilot w/brass bushing replacing solid pilot if need be, but .177 reamer is already pretty tiny without drilling/tapping end for pilot sleeve.
3) Now this might be a silly question, but I’m new at this & need/want to learn sometime anyways, soooo - how many flutes/cutting edges? Have read that you generally don’t want all your cutting edges to coincide with rifling lands to prevent “train-tracking” (“bump, bump, bump” while reaming). My barrel has 12 lands/grooves, so should I make the reamer with 5 flutes (1 flute always in contact with land), or could I get away with 3 or 6 flutes? I don’t have a spin index so will be using a hex collet block in vice to index flutes, hence the 3 or 6 flute reference. 5 flutes @ 72* apart might be difficult for me to accomplish accurately without a spin index…
My apologies for all the noob questions, just want to make sure I’m going at this the right way & not fubar a $100 barrel!
Thank you very much for your time & any insight you can offer…
Todd