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Coolant pressure QT-8

Captdave

Titanium
Joined
Sep 24, 2006
Location
Atlanta, GA
I have always had problems getting enough coolant pressure on this machine to use an index-able drill even have one of the wash down ports plugged. Today I had to tear into the small block on the turret housing where the coolant goes thru and meets up with the backside of the turret. Needless to say it had its fair share of crap in it.

While I had it apart it appears that the inlet side of block has an Allen head screw that I think holds the brass bushing on the other end that holds the Teflon? seal that touches the back side of the turret. There doesn't seem to be much room for the coolant to go around the screw head and enter the port, real screwy design. Also, on the top of the block there is another setscrew that has a sharp point on it but doesn't seem to be holding thing, could this be a pressure adjustment?

I didn't have time to monkey around as I needed to get a job finished but now think I should have left that screw backed out some to see if I could get a little more pressure. I need to make a new seal for the turret and was thinking about making one out nylon.

For those that have QT-8 and have probably had similar issues what do you think? I'm sure open to ideas:nutter:
 
I've seen where the turret itself will have resprictions in the porting from years of build up. Taking the turret off and cleaning it might help. There is no pressure adjustment on the coolant block that I know of. I have replaced the pump with higher presure pumps for customers that have needed it
 
Dave,

I know what you are talking about with the pressure. I run quite a bit of plastic and aluminum and am always pulling that block off. I would try to adjust the screws and compare the difference.

As far as the new gasket where the turret mates up mine had a rubber gasket. I have a customer that makes gaskets and he cut me a neoprene one whick works great.

Michael
 
I'm alwasy taking the plug out of the side of the turret and cleaning the chips that get caught up there and have added some extra filter material in the chip pan to help reduce the amount of fine chips that get picked up.

I have replaced the pump with higher pressure pumps for customers that have needed it
Would you happen to recall where you found the higher pressure pump or can point me in the right direction to find a replacement that wouldn't require too much modification to install? I rarely have any down time on this machine to spend on modifications:)
 
we replace them with Walrus brand pumps.

depending on the depth of your tank you'll need a 3 or 4 stage pump. i don't have the brochure in front of me but i want to say you can get 120 psi. I want to say stock is less than 80 when new. I've just sat down and started to celebrate the weekend so i maybe remembering wrong.

Justin Terry
 
Dave,

Check Ebay for "coolant pump" in Business and Industrial. A load of pumps available!

You can kinda tell the power of a pump by the AMPS it draws. Your factory pump is probably a 1.5A maybe? So, a 5A pump would be about 3 times the pressure.

Watch the immersion length of a new pump, and the motor height. You want it to fit...

Might have to install a new motor contactor and heater for a new pump. Check back here for help on that...

Greg
 
the pointy screw lines up with the -v- in the brass bushing to hold it in place, the socket head and the spring let the piston spring back and forth to close off coolant while the turret is indexing if your plastic bushing that rides on the turret is worn it will not open this system up fully. those machines have decent coolant from the factory. i would say before you buy a walrus pump (a good choice however for extra coolant without going to true "high pressure") i would pull that whole system apart clear back to the pump, there is surely stuff in every corner and fitting slowing down your flow get a piece of wire through all the hoses. i put y-traps at the pump in front of the check valves on mine and had few problems since. another common problem is someone over tightens the big plug just back from the coolant block, this will cut off flow around that corner.
 
I had a little time on Friday to pull the block off again and make a new seal/bushing out of some nylon that I had lying around. Pulled all the brass parts out of the block and as Wippin boy said the V shaped set screw on top held it together. The spring loaded plunger was stuck in the depressed position and took a little polishing to get it freed up and cleaned out all the trash caked inside.

Wow What an improvement in pressure! I'll have to snake out all the lines as suggested as I'm sure there more trash there as well.

I'm not familiar with the bag filter that Ox mentioned, where do you find them and do they go in the tank before the pump or in the pressure line after the pump?

While were on the subject of coolant and trash, at least once a month I have to pull the big steel screen off the chip pan and clean out all the chips that fall thru the screen and fill up the pan. Any ideas on adding a finer screen over the top of the factory model?
 
bag filters are an excellent system when your after really clean coolant
5168kp1s.gif
http://www.mcmaster.com/#filter-bag-housings/=91zna1

but a little bit pricey and perhaps overkill if all your after is keeping trash out of the lines
a good y-strainer

strainerss.gif
http://www.mcmaster.com/#y-style-strainers/=91zmb0

will probly suffice
 
I run course filters in my bags here.

They are only rated to 100 PSI. If running a std pump - you can put them after it.

If running a HP pump - you will want to run it before. (Likely between a low P pump and the HP pump?)


Too fine of a filter can be a bloody nightmare! I once setup a machine to use big screw-on filters for big diesel engines. Not sure where I got the fixture, but we got filters from John Deere for it. Cripes sakes I was plugging it up as quickly as 45 minutes! Went to a course bag filter (small unit) and that lasted 2 days on the same job!



--------------------

Think Snow Eh!
Ox
 
Kevin,

Thanks for the info I'll give the Y strainer a try. What size screen strainers and mesh size would you recommend for this application? I'm out flying this week would you happen to know what size fittings the QT-8 uses?

You had also mentioned about the plug in the side of the turret that sometimes gets over tightened and cut down the flow. The plug that was in there when I got the machine looked like a large set screw but it leaked like a sieve so I replaced it with a standard 1/4 brass plug. I think it should be a metric pipe thread but I have no clue what size.
 
We have Superflow by Graymills on one of our Bosto's.
I clean it out about once a year.
Then again we just do engraving with it
so very little material removal.
 
i would buy a 3/4" npt trap with about a 30 mesh even if your pump is 1/2" you can get a couple reducing bushings at the local hardware and the 3/4" gives you decent volumn

the plug i'm takin' 'bout is the one inside the arrows

qtcool.jpg


and i would guess that to be 1/2" (maybe 3/8") bspp
but thats a wag

ox is right on about bags
had a boss once that figured he could stop coolant from going bad by using a 10 micron bag because that is a small enough hole to catch bateria.
yeah right
bags lasted about 4 minutes
 
Well gee thanks fellas! :toetap:


I have never had this happen before, but I have had the ports on both turrets plugged this last cpl weeks! (Bin milling a lot of alum) I seem to have been able to blow the one wad back out the hose with air at the toolholder. (after splitting the hose...)

But the other'n just wasn't goin' fer that. She had a little more fight in her. :angry:

Ended up having to pull the turret off this morning and actually git in to see the problem. I found some decent sized chips in there. Not qiet sure how they got in there, but irrigardless - they did! Just too big to make the 90* corner at the bottom. And likely wouldn't have been able to fit through the spring loaded brass fitting anyway...

Alls good now....


(Non-Mazak machine)


I am conguring up a plan to mount ONE Bag Filter on a two turret/pump machine currently. Now I gotta go find my spare filter housing.... ????


-------------------

Got Coolant!
Ox
 








 
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