SQT 18MY coolant block

I pulled the coolant block off so we could remake the brass piston out of 316ss in prep for a 1000psi unit I have waiting.

The new part is made and I just got to wondering over the weekend, is there just the one brass part in there that needs remade?

I'm not fully sure how this block works. I pulled the plastic/rubber/whatever it is seal off the snout of the brass piece and then just pulled the brass piece out of the block. Didn't see any springs or anything.

Measured up the piece and had it remade.

The o-rings and turret seal look to be in good condition. Are these items that should be replaced? I didn't see any chips or debris in the block or in any of the lines. Previous to disassembly the coolant flow was pretty reasonable.

How exactly does this system work?

Are there any exploded diagrams anywhere (I haven't run across any)

Thanks!

if its the device i am familiar with (t-plus vintage dualturns and sqt's), they are actualy a hydraulic pistin driven in and out by a valve. thats why all the o-rings and cross holes in the block

Yep, T-Plus control. 1996 Sqt 18my

you gotta watch that system for dumping all the oil in the chip tank
o-rings on that piston will fail and pump the hydraulic tank dry lickidy split.

wippin' boy said:

you gotta watch that system for dumping all the oil in the chip tank
o-rings on that piston will fail and pump the hydraulic tank dry lickidy split.

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I get that impression from reading through old threads.

Is the hydraulic pressure only to force the seal into the back of the turret?

I put in the SS piece. I reused one of the o-rings as it wasn't bad. The other was on its last legs so I put in another one.

No hydraulic leaks that I am aware of. When I run the coolant, i see the same sort of pressure/flow I had before, which is nice, but i notice a leak on the back of the turret. It is possible it was leaking here before and I never noticed it.

Presumably it is the seal between my new SS piece and the turret sealing surface.

Is it possible coolant is leaking from somewhere else in the block? Am I ok to run?

I feel like im in the middle of a mine field. Everything looks ok as far as I can tell, but you know. . .

a dribble at the back of the turret is common
if the oil is leaking it will come out through the coolant holes on the front of the turret even if the coolant is off
if your still running stock coolant pump i dought the coolant is coming from anywhere else.
at standard coolant pressure i have never seen any other issues there.
1000 psi ? now that may be a differant story, your at or near the same pressure as the hydraulic system.

wippin' boy said:

a dribble at the back of the turret is common
if the oil is leaking it will come out through the coolant holes on the front of the turret even if the coolant is off
if your still running stock coolant pump i dought the coolant is coming from anywhere else.
at standard coolant pressure i have never seen any other issues there.
1000 psi ? now that may be a differant story, your at or near the same pressure as the hydraulic system.

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Re: the pump, it's not stock. I don't know what pressure or gpm it is, but it's not the original Mazak pump. Id be surprised if it was more than 100psi though.

I bought a Chipblaster unit after they told me the SQT's can be fitted with the 1kpsi system after modifying the piston block. . .

Just an update. . .

finally got the ChipBlaster unit hooked up.

Holy cow, what a difference. My leak at the back of the turret is now a hemorrhage and the pump only develops 400psi.

Even at that, I was able to double sfm on a 1.5" sandvik 880 drill.

I have a major leak somewhere that lets coolant down onto my floor so I'm switching back to the original pump till I can get that fixed.

I'd like to put in a new turret-piston block seal as well in hopes that my major leak becomes smaller and my psi will go up even more.

Even if all I ever get is the 400 psi I'll be happy. It's like going from a super soaker to a fire hose.

So how did it go ever fix the problem I have a couple SQTs I'd like to modify. T-32 though, did you need a different seal kit for the higher pressure?

earthstore88 said:

So how did it go ever fix the problem I have a couple SQTs I'd like to modify. T-32 though, did you need a different seal kit for the higher pressure?

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This piston block design is kind of sucky in my opinion. The stock seal will not even come close to holding up to high pressure. You will need to machine yourself another piston from brass that is longer to take the place of the seal. It's brass against the back of the turret (how chipblaster does it)

Now, the o-rings that are in there, they like to fail. A lot. My SQT hyd system pressure is 853 psi. Running coolant pressure above that isn't so great. When the o-rings fail, coolant forces its way into the hyd system, fills the hyd tank and pushes all your hyd oil all over the floor.

Regulating the pressure down to 750psi cured that, but now when the o-rings fail, hyd oil leaks into the coolant. Not a huge deal for me because we skim it, but it's still a hassle.

I'm very close to a better coolant block design that should completely separate the hydraulic system and coolant system. There are a couple issues to work through to make it work correctly still though.

Also, I ended up helicoiling the piston block holes on the turret. One of them stripped cause we had the block on and off so much so now they're 1/4-20's

HP coolant is worth it.

Or it will be

Or it will be

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spoken like an application engineer

wippin' boy said:

spoken like an application engineer

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I just play one on TV