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Posted: 2/17/2016 11:34:42 PM EDT
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Someone who is a professional machinist suggested that I should get these for drilling the deeper holes in 80% lowers. He said that they do a much better job of augering out the chips amongst other advantages over standard twist flute drill bits especially for holes deeper than 4x diameter. Has anyone got any experience with this kind of bit? They are quite a bit more expensive than standard flute bits.
Also what do people think about bits that are TiN coated? Other than the pretty gold color are they really that much better than plain HSS for drilling in aluminum? |
I only use Parabolic ColbaltHSS drill bits when I machine my lowers on my small CNC mill..
Some say the coating helps...but if you are using good quality cutting lube, I don't see a difference. I said this in another post..Also Peck drill your holes to clear the flukes and break the chips. This will give you a clean and perfect hole! Ca_Longshot |
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I'm certainly no expert on TiN coated bits, but both personal experience and some reading that I have done have convinced me that it offers no advantage over uncoated HSS when drilling aluminum, and in fact is often worse since chips have a tendency to 'weld' to the TiN coating.
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I've been using parabolic bits (in conjunction with a drill press) and I swear by them. To me there is no contest between a standard twist drill and a parabolic when drilling the FCG pocket. I have been able to reduce the drilling of each hole down to two cylces. You can drill about halfway to 3/4 of the way down the pocket before you have to lift the drill to clear the chips. Down again and the hole is done. With a standard twist drill it was in out a dozen times for one hole. I use these bits: http://www.mcmaster.com/#=116d6qw Yeah they cost more but I have cut multiple lowers with one bit and it is still sharp. Just make sure you use plenty of lube. Edit: No opinion whether TiN coating is superior. McMaster offers this bit in uncoated, black oxide, and TiN. I've been using the uncoated ones. |
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Quoted:
I've been using parabolic bits (in conjunction with a drill press) and I swear by them. To me there is no contest between a standard twist drill and a parabolic when drilling the FCG pocket. I have been able to reduce the drilling of each hole down to two cylces. You can drill about halfway to 3/4 of the way down the pocket before you have to lift the drill to clear the chips. Down again and the hole is done. With a standard twist drill it was in out a dozen times for one hole. I use these bits: http://www.mcmaster.com/#=116d6qw Yeah they cost more but I have cut multiple lowers with one bit and it is still sharp. Just make sure you use plenty of lube. Edit: No opinion whether TiN coating is superior. McMaster offers this bit in uncoated, black oxide, and TiN. I've been using the uncoated ones. Parabolics are extremely useful when deep drilling, when the length of the hole is 5X to 8X diameter. You still have to be careful not to push them to hard, the bit will flex and that will cause the hole to wander. |
| I posted in another thread about drilling lowers and stated to use a parabolic flute drill. There was also a link to a set of them on Amazon. They're the same drills we use in our machine shop and get good results from them (we're an aerospace company that cuts mainly aluminum) the brand is YG1. The really nice thing is you don't have to peck with them unless you're drilling really deep. Just keep them lubed up and run them straight through, turn the drill press off and retract the drill and you'll have reamer quality finishes. |
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Quoted:
I posted in another thread about drilling lowers and stated to use a parabolic flute drill. There was also a link to a set of them on Amazon. They're the same drills we use in our machine shop and get good results from them (we're an aerospace company that cuts mainly aluminum) the brand is YG1. The really nice thing is you don't have to peck with them unless you're drilling really deep. Just keep them lubed up and run them straight through, turn the drill press off and retract the drill and you'll have reamer quality finishes. I just ordered some of that brand off Amazon for the sizes needed for the bulk drilling in 80% AR lowers. I'm looking forward to trying them out and seeing how much better they work than standard twist bits. |
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Quoted:
I just ordered some of that brand off Amazon for the sizes needed for the bulk drilling in 80% AR lowers. I'm looking forward to trying them out and seeing how much better they work than standard twist bits. Quoted:
Quoted:
I posted in another thread about drilling lowers and stated to use a parabolic flute drill. There was also a link to a set of them on Amazon. They're the same drills we use in our machine shop and get good results from them (we're an aerospace company that cuts mainly aluminum) the brand is YG1. The really nice thing is you don't have to peck with them unless you're drilling really deep. Just keep them lubed up and run them straight through, turn the drill press off and retract the drill and you'll have reamer quality finishes. I just ordered some of that brand off Amazon for the sizes needed for the bulk drilling in 80% AR lowers. I'm looking forward to trying them out and seeing how much better they work than standard twist bits. Make sure you got the parabolic and not standard, I believe they offer both. |
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Quoted:
Make sure you got the parabolic and not standard, I believe they offer both. Quoted:
Quoted:
Quoted:
I posted in another thread about drilling lowers and stated to use a parabolic flute drill. There was also a link to a set of them on Amazon. They're the same drills we use in our machine shop and get good results from them (we're an aerospace company that cuts mainly aluminum) the brand is YG1. The really nice thing is you don't have to peck with them unless you're drilling really deep. Just keep them lubed up and run them straight through, turn the drill press off and retract the drill and you'll have reamer quality finishes. I just ordered some of that brand off Amazon for the sizes needed for the bulk drilling in 80% AR lowers. I'm looking forward to trying them out and seeing how much better they work than standard twist bits. Make sure you got the parabolic and not standard, I believe they offer both. Yes, I checked them to make sure they all were parabolic. |
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