[4]

hydraulic pump question for barrel flush system

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

diamond

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Apr 26, 2018
Messages
28
Likes
16
#1
My intent is to build a barrel flushing system for cutting rifle chambers. Yeah, another one of those threads! lol

Specific question is what does anyone here think about running a hydraulic pressure pump (small ones used for small lifts etc) at a lower RPM than nominally used for typical hydraulic pressure applications.

I see a lot of threads talking about using carbonator pumps. They're still kinda pricey, upwards of $300 or more. A small hydraulic pump can be found pretty cheap new (< $100). Used even cheaper.

Something like this https://www.ebay.com/itm/Hydraulic-...ium-NEW-/232907898475?&_trksid=p2056016.l4276

Run off a 1725 rpm motor with pulleys to spin the pump at it's min rated RPM (700) and pushing dark cutting oil. Flow requirements for chamber cutting is not high. 1-2 gpm should be enough, I think. I don't know if I can get away with a 1/2 horse motor, I'm thinking I might with it geared down like that. The hp ratings for full pressure applications are much higher but I'm hoping this would scale down accordingly for the pressures I want to run at.

Assuming it would work, one concern is over pressure when the reamer pilot engages the rifling, restricting flow and blowing my lines or rotary coupling or something else. I want to keep the whole system to under 150psi-200psi max. My target is 60-100 nominal when chamber cutting. Even at minimum rpm a pump like the above is able to produce 1000psi. I don't know if I can control that with just a manual bypass valve or if I'd need a real pressure regulator valve (expensive!). A manual bypass valve might work, if I am careful to ease into it.? Maybe? I'm thinking pressure should stay fairly consistent once the pilot is in the rifling.

Any thoughts? Bad idea?

I'm in the process of researching the whole system which will involve pump & motor, filtration (10-micron), rotary coupling, air purge, and of course sundry plumbing/valves/gauges/etc. I'm hoping to keep this all to $500. We'll see.

Thanks! Dave
 

Bob Korves

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Joined
Jul 2, 2014
Messages
5,845
Likes
6,157
#2
It sounds like you need a relief valve with a weak enough spring or spring setting to keep the pressure down where you want it. For what you suggested, the relief valve should be able to bypass the entire pump flow volume at any bypass pressure setting down to zero. Relief valves are simple and common devices, you should be able to find an appropriate one for not much money, or even make one. They are simple devices.
 

JimDawson

Global Moderator
Staff member
H-M Platinum Supporter ($50)
Joined
Feb 8, 2014
Messages
7,254
Likes
5,534
#3
I used an oil furnace feed pump. Not sure what the pressure rating is, but have an adjustable relief on them. They are designed to run with about a 1/2 HP, 1725 RPM motor.
 

derf

Brass
Registered
Joined
Oct 3, 2015
Messages
655
Likes
764
#4
You are over thinking this, it doesn't have to be that complicated. I build a system 20 yrs ago, starting with a hi pressure pump that led to numerous headaches. I found that you don't need all that pressure, just flow. I ended up using a Teel centrifugal pump that has served me well without the aggravation of all the valves, bypasses and filters.
DSC02629.JPG
It provides plenty of pressure to flush out chips without the need for a by pass. A centrifugal pump can be regulated by a simple ball valve without the pressure build up like with a gear pump.
DSC02634.JPG
A rotary fitting on this muzzle clamp feeds the oil through the barrel, and when it exits on the muzzle side, it is caught in a trough mounted on the tool post, in turn re directs it down to another trough with dams in place to catch chips. The oil returns to the sump, which has a series of dams and over flows to keep the solids on the bottom.
DSC02631.JPG
I've been using this system for 18 yrs with no complaints. I also might mention that I use transmission fluid for cutting oil. It seems to flow and work better than dark cutting oil.
 

diamond

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Apr 26, 2018
Messages
28
Likes
16
#5
Bob I like your thinking, yeah I could make a pressure relief valve. Be a fun project on the lathe.

I've got a lead on a 1hp motor and hydraulic pump for $65. It's worth that for the motor alone (that runs) so I'm gonna give it a try.

If I can find similar deal on a good oil furnace feed pump tho, I may look into that as well.

derf I'll consider that. I'm going off the experience of some local smiths I know. They're happy with the way their systems work and I'm impressed with their results but as with a great many things, there are often more than one good way to do it.
 

Bob Korves

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Joined
Jul 2, 2014
Messages
5,845
Likes
6,157
#6
Bob I like your thinking, yeah I could make a pressure relief valve. Be a fun project on the lathe.
I've got a lead on a 1hp motor and hydraulic pump for $65. It's worth that for the motor alone (that runs) so I'm gonna give it a try.
The only things you need for the pressure calculation are the diameter of the ball where it seats and the actual spring pressure on the ball.
 

derf

Brass
Registered
Joined
Oct 3, 2015
Messages
655
Likes
764
#7
One problem I had with a hi pressure system, is you definitely have to have the tightest bushing on your reamer. If not, it caused chatter, especially with a 6 flute reamer going into a 4 groove barrel.
 

eugene13

Active Member
Registered
Joined
Nov 19, 2014
Messages
338
Likes
350
#8
Maybe use a power steering pump, a place where i once worked did gun drilling, that's what we used.
 

diamond

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Apr 26, 2018
Messages
28
Likes
16
#9
00000_45jLQxlakv6_1200x900.jpg
Thanks for all the tips guys. I went ahead picked this up for 65 bucks off craigslist. A running 1hp motor is worth that alone and if the pump doesn't work out I can take it off and rig up a different pump. The unit is from a car lift I'm pretty sure. Obviously capable of generating way more pressure than I want so thats why the relief valve. Ordered a 25-175psi adjustable bypass for $40. Some ball valves, plumbing and a pressure gauge and i'll have a way to test the bypass valve and flow rate. I'll let you know. Also picked up a Deublin rotary coupling on ebay for $50 and a $30 external oil filter mount and cartridge. I'm hoping when all is said and done I'm into this for under $250 total.
 

Bob Korves

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Joined
Jul 2, 2014
Messages
5,845
Likes
6,157
#10
One problem I had with a hi pressure system, is you definitely have to have the tightest bushing on your reamer. If not, it caused chatter, especially with a 6 flute reamer going into a 4 groove barrel.
I would use a spiral cut reamer to ream a barrel with existing rifling grooves. That is the class of work they are designed and made for. It shouldn't matter how many grooves are in the barrel, well, two grooves might cause problems...
 

aliva

Active User
H-M Supporter - Gold Member ($25)
Joined
Feb 28, 2012
Messages
328
Likes
186
#11
Try a parts washer pump low pressure but high volume. No relief valve required I think that's all you need to supply flooding oil. Dark cutting oil should be around 5 to 10 wt. For $30.00 it's worth a try
 
[6]
[5] [7]
Top