Pump threads and shaft compatibility between different brands.

[Diving Gecko]

When you release air from the gun - what do you do? You take a piece of hard wire or a nail and push the pin in the valve to release air. A very minimal effort is required because the surface area is tiny.
[EDIT]...

Ah, I see what you are saying and we have been talking about two different things. But they are connected.
Hear me out. While it might not take much force to open the valve itself, what happens in the moment you do that is that air will rush out of the gun into the bigger space between the valve and the front of the gauge. The pressure will reach an equilibrium with the pressure inside the gun and the gauge will stop to rise. But this space has a bore of Ø10mm, and at 20 bar that will result in around 16kgf of force wanting to spit the gauge back out. At 40 bar, it is double that. That's what I have been babbling on about

 

[vrokhlenko]

Ah, I see what you are saying and we have been talking about two different things. But they are connected.
Hear me out. While it might not take much force to open the valve itself, what happens in the moment you do that is that air will rush out of the gun into the bigger space between the valve and the front of the gauge. The pressure will reach an equilibrium with the pressure inside the gun and the gauge will stop to rise. But this space has a bore of Ø10mm, and at 20 bar that will result in around 16kgf of force wanting to spit the gauge back out. At 40 bar, it is double that. That's what I have been babbling on about

Once again, to me the biggest problem was the air leak. Maybe I did not design it right. But I go by feel when loading so I know if need to give it a few more strokes. To me the most time-consuming and tiresome is cutting o-ring grooves - I do it with 0.05mm precision and it is a pain in the ass. I even have a special carbide groove cutting insert but taking constant measurements to make sure the depth of the groove is correct is very exhausting

 

[Diving Gecko]

Once again, to me the biggest problem was the air leak. Maybe I did not design it right. But I go by feel when loading so I know if need to give it a few more strokes. To me the most time-consuming and tiresome is cutting o-ring grooves - I do it with 0.05mm precision and it is a pain in the ass. I even have a special carbide groove cutting insert but taking constant measurements to make sure the depth of the groove is correct is very exhausting

I don't use much carbide. I have some inserts made for cutting alu which are sharper than carbide and cuts plastics and alu beautifully. I even use it on steel now. I think since my lathe is not that stiff, the sharper inserts produce better results for me. I think we hold about the same tolerances but I also have a cheap man's DRO on mine which helps a lot. It's just digital calipers with magnets that I can put on the axis needed.
At some point, I did have a more advanced DRO which can be built cheaply but had some issues with it and pulled it off and haven't gotten around to putting it back on.
Some pics of both DRO solutions here:

The Ultimate Travel Oleo? - A Custom-Sized Mirage 93

Rescues in Titanium Remember the busted tap in my titanium pump adapter? Well, I was about to send it to South China to have the s@#* EDM'ed out of it but then I spent a bit of time reading up on this and someone somewhere online mentioned that diamond coated "dremel bits" should be able to cut...

forums.deeperblue.com

 

[vrokhlenko]

I don't use much carbide. I have some inserts made for cutting alu which are sharper than carbide and cuts plastics and alu beautifully. I even use it on steel now. I think since my lathe is not that stiff, the sharper inserts produce better results for me. I think we hold about the same tolerances but I also have a cheap man's DRO on mine which helps a lot. It's just digital calipers with magnets that I can put on the axis needed.
At some point, I did have a more advanced DRO which can be built cheaply but had some issues with it and pulled it off and haven't gotten around to putting it back on.
Some pics of both DRO solutions here:

The Ultimate Travel Oleo? - A Custom-Sized Mirage 93

Rescues in Titanium Remember the busted tap in my titanium pump adapter? Well, I was about to send it to South China to have the s@#* EDM'ed out of it but then I spent a bit of time reading up on this and someone somewhere online mentioned that diamond coated "dremel bits" should be able to cut...

forums.deeperblue.com

I beat you on a cheap DRO front Mine cost 5 dollars each and are spring loaded. Made out of the digital tire/tread gauges. X-axis is on magners, Y-axis is attached to a bracket. They take less space than the digital calipers. Because of the backlash the DROs that counts revolutions are inaccurate. The optical ones cost $400. Spring load is the way to go.

 

[Diving Gecko]

Spring loaded is a good idea. I use a magnet on the front of the “feeler”. And it’s indeed a digital tire thread depth gauge, too as the pics show. But couldn’t remember the name for them so just called them calipers.

Five bucks is cheap but I think in China I might even have paid 1-2 dollars less. Just crazy cheap. I have a cut down caliper on the tailstock which has been very handy for putting a shoulder in exactly the right place to hold an o-ring. I use that function quite a lot.
Once I start making money again I might splash on magnetic scales. They are much smaller than glass scales and I can get it on two axis for perhaps usd170. But that’s without the readout - but I’ll connect them to a Bluetooth tablet via a control box designed by the Yuri chap I mentioned in the same thread I linked to. I already have the parts for the box and the tablet. I did have that up and running before with cheaper caliper type scales but they were not reliable and would loose steps too often. Maybe a noise issue, not sure. But the tablet DRO was awesome hence why I’m thinking of pairing it with much better magnetic scales. Though spending 170 bucks is a lot on this cheap a lathe.


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[vrokhlenko]

Spring loaded is a good idea. I use a magnet on the front of the “feeler”. And it’s indeed a digital tire thread depth gauge, too as the pics show. But couldn’t remember the name for them so just called them calipers.

Five bucks is cheap but I think in China I might even have paid 1-2 dollars less. Just crazy cheap. I have a cut down caliper on the tailstock which has been very handy for putting a shoulder in exactly the right place to hold an o-ring. I use that function quite a lot.
Once I start making money again I might splash on magnetic scales. They are much smaller than glass scales and I can get it on two axis for perhaps usd170. But that’s without the readout - but I’ll connect them to a Bluetooth tablet via a control box designed by the Yuri chap I mentioned in the same thread I linked to. I already have the parts for the box and the tablet. I did have that up and running before with cheaper caliper type scales but they were not reliable and would loose steps too often. Maybe a noise issue, not sure. But the tablet DRO was awesome hence why I’m thinking of pairing it with much better magnetic scales. Though spending 170 bucks is a lot on this cheap a lathe.


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I know about Yuriy and his efforts with the caliper interface. My readout is pretty accurate. The only problem is - if it does not move for 5 minutes - it turns itself off. I use magnets to keep the body of the gauge in place on the tailstock (I cut it open and stuffed it with magnets). The probe is spring-loaded.
I know that you are a photographer (it is up to you to figure out how I know ) Can you make money doing just that?

 

[Diving Gecko]

As for hitting the right depth for a groove. I have started trusting my leadscrew a whole lot more and have had very good tolerances on my work for a while. So, I would basically check the depth I am at and then do the math on how much more I need to take off in the final cut and figure out how much that is on the cross slide leadscrew markings. And then for the final cut I just count markings on the leadscrew. Maybe my leadscrew is more consistent than other cheap ones but it has worked beautifully. I often design my parts with double o-rings so when I go to cut the second grove I just hit the same mark on the leadscrew and they end up the same. I guess it’s the old school way of doing it;-)


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[vrokhlenko]

As for hitting the right depth for a groove. I have started trusting my leadscrew a whole lot more and have had very good tolerances on my work for a while. So, I would basically check the depth I am at and then do the math on how much more I need to take off in the final cut and figure out how much that is on the cross slide leadscrew markings. And then for the final cut I just count markings on the leadscrew. Maybe my leadscrew is more consistent than other cheap ones but it has worked beautifully. I often design my parts with double o-rings so when I go to cut the second grove I just hit the same mark on the leadscrew and they end up the same. I guess it’s the old school way of doing it;-)


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Too lazy to count revolutions. But it is the only way to go if you do not have a dro

 

[Diving Gecko]

I know about Yuriy and his efforts with the caliper interface. My readout is pretty accurate. The only problem is - if it does not move for 5 minutes - it turns itself off. I use magnets to keep the body of the gauge in place on the tailstock (I cut it open and stuffed it with magnets). The probe is spring-loaded.
I know that you are a photographer (it is up to you to figure out how I know [emoji4] ) Can you make money doing just that?

Oh, I think my tire gauges stay on. Not 100% sure but I feel like I would have been frustrated and remembered if they turn off. I guess a different FW as I wouldn’t be surprised if most of these boards come from the same place.

It’s no secret that I’m a photographer.
Maybe we know some of the same people. Maybe Vad;-)

As for making a living. Yes, I sure used to be able to - back when print media was alive I could even make a living doing mostly stories that I cared about and pitched to various magazines in Europe and the US. But print media is dying so a lot of us have moved into corporate work a bit - but the virus will make this a horrible year. Companies will hold onto their money and definitely not spend it on things like photography. And print media probably will, too. And I can’t move around in the world even if someone wanted to hire me.
So, yeah, it’s going to be very hard for a long time. But this is what I wanted to do so no sense in whining too much and many other people face grave challenges these days, too in terms of their livelihood. Imagine being in the aviation or hospitality industry...


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[vrokhlenko]

Oh, I think my tire gauges stay on. Not 100% sure but I feel like I would have been frustrated and remembered if they turn off. I guess a different FW as I wouldn’t be surprised if most of these boards come from the same place.

It’s no secret that I’m a photographer.
Maybe we know some of the same people. Maybe Vad;-)

As for making a living. Yes, I sure used to be able to - back when print media was alive I could even make a living doing mostly stories that I cared about and pitched to various magazines in Europe and the US. But print media is dying so a lot of us have moved into corporate work a bit - but the virus will make this a horrible year. Companies will hold onto their money and definitely not spend it on things like photography. And print media probably will, too. And I can’t move around in the world even if someone wanted to hire me.
So, yeah, it’s going to be very hard for a long time. But this is what I wanted to do so no sense in whining too much and many other people face grave challenges these days, too in terms of their livelihood. Imagine being in the aviation or hospitality industry...


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It should be no whining from those who want to do what they like rather than what is needed. I know it is firsthand . I had no idea that you are a photographer till yesterday but I figured it out. Might tell you how some day Time for me to sleep. Talk to you later

 

[Diving Gecko]

Too lazy to count revolutions. But it is the only way to go if you do not have a dro

Gotcha. I didn’t do it in the beginning cuz I just assumed the threading on the leadscrew couldn’t be trusted on this cheapo lathe. Turned out, it’s fine. So, I use a mix of the DROs and the old school counting;-)
Consider giving the silvery, shiny inserts for alu a go. They are sharp and cut really nicely

 

[vrokhlenko]

Gotcha. I didn’t do it in the beginning cuz I just assumed the threading on the leadscrew couldn’t be trusted on this cheapo lathe. Turned out, it’s fine. So, I use a mix of the DROs and the old school counting;-)
Consider giving the silvery, shiny inserts for alu a go. They are sharp and cut really nicely

I never threaded on my lathe. Watched videos and not sure I will ever do it. My friend threads on his lathe manually - sets the pitch and rotates the chuck by hand. It is slow but he is in total control. I thread with taps and dies manually. have some high quality USA-made stuff for that

 

[Diving Gecko]

Yeah, it was slightly scary to start but now I don’t mind. But it’s much easier if your lathe actually has enough power at slow speed. Most of the mini lathes don’t so you end up having to run them fast which is no fun for threading. For that reason I actually upgraded my motor. I have a beefy brushless in there now and can run it down to less than 80rpm and it just doesn’t bog down. Makes threading a whole lot more enjoyable.
I am still not 100% friends with the thread dial and disengaging the halfnuts though so I tend to keep them engaged the whole time and just reverse the machine between cuts.

On that note, I may very well be upgrading to an electronic leadscrew in the future - then I also don’t need to fiddle with the change gears anylonger. Another chap on YouTube is developing a really cool system but I missed out on his first batch of controller boards. I’ll update this post with links later but I think his channel might be Hough42.

Another thing that helps is threading away from the chuck. Joe Pie has a great video on that on his YouTube channel.


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[vrokhlenko]

Yeah, it was slightly scary to start but now I don’t mind. But it’s much easier if your lathe actually has enough power at slow speed. Most of the mini lathes don’t so you end up having to run them fast which is no fun for threading. For that reason I actually upgraded my motor. I have a beefy brushless in there now and can run it down to less than 80rpm and it just doesn’t bog down. Makes threading a whole lot more enjoyable.
I am still not 100% friends with the thread dial and disengaging the halfnuts though so I tend to keep them engaged the whole time and just reverse the machine between cuts.

On that note, I may very well be upgrading to an electronic leadscrew in the future - then I also don’t need to fiddle with the change gears anylonger. Another chap on YouTube is developing a really cool system but I missed out on his first batch of controller boards. I’ll update this post with links later but I think his channel might be Hough42.

Another thing that helps is threading away from the chuck. Joe Pie has a great video on that on his YouTube channel.


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You are way ahead of me in this department. I bought and inherited a lot of high quality taps and dies so I am OK for small diameters. Of course for the larger diameters lathe threading is mandatory. I do not have much to work on - just invent small projects here and there. hand threading is tricky since suggested major diameters are often wrong.

 

[Diving Gecko]

You are way ahead of me in this department. I bought and inherited a lot of high quality taps and dies so I am OK for small diameters. Of course for the larger diameters lathe threading is mandatory. I do not have much to work on - just invent small projects here and there. hand threading is tricky since suggested major diameters are often wrong.

I managed to make a slightly tilted thread on a barrel with a hand die so I think that sped up my willingness to get started on doing it on the lathe. The middle step - which I still use sometimes - was to make die holders that fit onto the tailstock in aiding to keep everything concentric. So, still manual but more or less using the lathe as a jig.


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[vrokhlenko]

I managed to make a slightly tilted thread on a barrel with a hand die so I think that sped up my willingness to get started on doing it on the lathe. The middle step - which I still use sometimes - was to make die holders that fit onto the tailstock in aiding to keep everything concentric. So, still manual but more or less using the lathe as a jig.


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In order for the thread to be perfect you must keep either a die or a tap under pressure. I have a special spring-loaded device to keep a tap concentric with the hole (I chuck either in a drill press or a lathe and turn the tap manually). As far as the die, I have a chuck in my tailstock and I press this chuck against the die while threading.

 

[stefpix]

First of all let me tell you that as you may notice by the nominal length there's not so much difference between a 65cm and a58 cm long gun.

This said I would recommend you to stay away from Jet series. I'll try to explain why:
the leverage system that from the trigger (52 in the diagram) starts and ends at the release tooth (50) (I hope that this is the correct english name) has its weak point in the hole present in the handle that make the trigger pin (45) move up and down. Since there'e no metal guard guide for the pin the hole soon or later will become oval and the oring will no more grant the seal

I received the Salvimar Predathor 55. Length is about right maybe 57 cm.
the 65 is actually 70 or 72 cm, so more than 10 cm difference.
it is worth having the same brand, so I can share pump and other parts.
Still have not used it. Weather has been bad. Covid epidemic canceled travel.

 

[Diving Gecko]

I received the Salvimar Predathor 55. Length is about right maybe 57 cm.
the 65 is actually 70 or 72 cm, so more than 10 cm difference.
it is worth having the same brand, so I can share pump and other parts.
Still have not used it. Weather has been bad. Covid epidemic canceled travel.

Congrats on the gun and that's a surprise with the 55 model actually being close to its designated length. I do have in my notes, and have told others, that Predathors are app. 7cm longer than their model name. So, how long is the stock shaft for your 55?

 

[burjegol]

regarding hand pumps for mares, I grew tired pumping it to desired bar pressure. so what I did was dismantled the tip, fit a 1/4" flare connection, then attach it to a gage, then to a nitrogen tank or scuba tank, and presto! I could get exact pressure I desire without sweat.
Gun is Mares cyrano 1.1 and 75 jet sten.

 

[burjegol]

Well, folks, this is what I've done with my Mares cyrano pump. I removed that adapter at the pump end, and fitted it with a 1/4" flare connection to accept a refrigeration tubing, than attach it to a pressurized cylinder. Mine was charge with 22 Bars Nitrogen.