Valve mod - pcp pistol

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   Looking good Pauly. Pity about the radius cutter not being as advertised.

The inlet screw does not really need the flat down the side and it causes more stress on the o-ring
to force it around a non-round shape. The air flows past a regular screw anyway
but if you must fill faster you can get a similar effect by oversizing the tap drill to 4.5 for M5 and 
leave the screw standard.

When you have stainless parts with a lot of machining time in them and the fastener
isn't working close to its capacity, it is advised to use larger tap drills to avoid broken taps.
Just adding 0.1mm can go from from walking on ice, to a walk in the park.

Anyone not having fun with stainless should try 303 grade for machining.
Not only stronger than 304 and 316 but much nicer to machine.

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BC_Clark Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 16 Feb 2024 Location: Auckland Status: Offline Posts: 7	Post Options Post Reply Quote BC_Clark Report Post Thanks(0) Quote Reply Posted: 24 Dec 2024 at 3:48pm
	Looking good Pauly. Pity about the radius cutter not being as advertised. The inlet screw does not really need the flat down the side and it causes more stress on the o-ring to force it around a non-round shape. The air flows past a regular screw anyway but if you must fill faster you can get a similar effect by oversizing the tap drill to 4.5 for M5 and leave the screw standard. When you have stainless parts with a lot of machining time in them and the fastener isn't working close to its capacity, it is advised to use larger tap drills to avoid broken taps. Just adding 0.1mm can go from from walking on ice, to a walk in the park. Anyone not having fun with stainless should try 303 grade for machining. Not only stronger than 304 and 316 but much nicer to machine.

JasonEdward Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 22 Sep 2024 Location: Waihi Status: Offline Posts: 138	Post Options Post Reply Quote JasonEdward Report Post Thanks(0) Quote Reply Posted: 06 Dec 2024 at 7:24am
	Yeah I thought a nice sharp drill was all i needed to drill S/S. Blunted drills, hardened stainless and a fitter mate taught me the error of my ways.

kruzaroad Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 03 Jul 2022 Location: Hastings 4 now Status: Offline Posts: 2468	Post Options Post Reply Quote kruzaroad Report Post Thanks(0) Quote Reply Posted: 06 Dec 2024 at 5:25am
	Lol. Sweet Pauly. Be a shame to have to use a less durable metal. Looking forward to progress resaults on pistols now you've beaten this problem.

Pauly5 Members Profile Send Private Message Find Members Posts Add to Buddy List Forum Moderator Joined: 11 Mar 2013 Location: Titahi Bay Status: Offline Posts: 1523	Post Options Post Reply Quote Pauly5 Report Post Thanks(0) Quote Reply Posted: 06 Dec 2024 at 5:01am
	Quick update on drilling. New bits arrived, halved drill speed, used new paste and it cuts like butter. What a relief, I was starting to hate stainless.

Pauly5 Members Profile Send Private Message Find Members Posts Add to Buddy List Forum Moderator Joined: 11 Mar 2013 Location: Titahi Bay Status: Offline Posts: 1523	Post Options Post Reply Quote Pauly5 Report Post Thanks(0) Quote Reply Posted: 05 Dec 2024 at 10:49am
	I had a good drill bit, but too much speed. Have got a couple of good 135 deg cobalt bits from Sulco now. Appreciate the help guys.

nunga Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Admin Joined: 09 Mar 2013 Location: Pukekohe Status: Offline Posts: 1043	Post Options Post Reply Quote nunga Report Post Thanks(0) Quote Reply Posted: 05 Dec 2024 at 9:43am
	Hard steel equals very slow drill speeds and use thread cutting paste with it. The slower you go the better. High speeds will only burn out your drill bit and work harden the metal even more. Those gold coated so called titanium bits are crap. Only good for soft metals like alloy.
	2nd place HP springer - WFTF World Championships 2014

kruzaroad Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 03 Jul 2022 Location: Hastings 4 now Status: Offline Posts: 2468	Post Options Post Reply Quote kruzaroad Report Post Thanks(0) Quote Reply Posted: 04 Dec 2024 at 6:19pm
	Yeah but the flooding pulls heat away from the metal and drill constantly, which im assuming a paste wouldn't, or at least as well.

Pauly5 Members Profile Send Private Message Find Members Posts Add to Buddy List Forum Moderator Joined: 11 Mar 2013 Location: Titahi Bay Status: Offline Posts: 1523	Post Options Post Reply Quote Pauly5 Report Post Thanks(0) Quote Reply Posted: 04 Dec 2024 at 6:11pm
	Thanks Kruz. Yea, I now have a couple of cobalt 4.2 mm bits on the way with the 135 deg point. I was probably spinning the drill at around 1000 rpm, so far too fast. I did a test hole at around 400 rpm and it was day and night. I got RTD metal cutting compound. Its a paste that sticks to the bit as opposed to flooding it.

kruzaroad Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 03 Jul 2022 Location: Hastings 4 now Status: Offline Posts: 2468	Post Options Post Reply Quote kruzaroad Report Post Thanks(0) Quote Reply Posted: 04 Dec 2024 at 5:39pm
	Just had nosey on web. Starts at around 400° depending on stainless. Recomends a cutting fluid, breaks to let metal cool if drilling to long and this Use a drill bit designed for stainless steel Use a cobalt or titanium nitride (TiN) coated high speed steel (HSS) drill bit with a 135° point. Begin drilling at a lower speed, around 30-60 surface feet per minute (SFM). Edited by kruzaroad - 04 Dec 2024 at 5:42pm

kruzaroad Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 03 Jul 2022 Location: Hastings 4 now Status: Offline Posts: 2468	Post Options Post Reply Quote kruzaroad Report Post Thanks(0) Quote Reply Posted: 04 Dec 2024 at 5:31pm
	Probly is to fast pauly. Was watching video a week or so back and dude was having trouble with the drill hardening stainless around holes. Apparently stainless tempers at very low heats. Might have to set up cutting fluid bottle with gravity feed and flow adjustment or something to keep temp down