Maka SM6-Pii

[Brian Holcombe]

Brian, The machines originally operated with no air blowout and for the most part worked well. The problems would occur if you had dull chisels and a fast feed rate, the chips will clog up and compress rather than flying up and out, once they start to clog the gullet and pack up in front of the chisel, it gets nasty real fast. So, sharp chisels, the correct chisel stroke ( longer is better) a good fast speed (you have to experiment and get a feel for that) and your good, add in air blowout or air through the chisel and you are golden. As far as the feed; proper bleeding is essential. The regulator valve, is controlled feed open return, and sometimes an air control valve like was on yours. The thing that i found is the regulator valve has several turns of adjustment, and i only ever used about 1/4 turn range, so i would put a heavier oil in the control cylinders. that gives a smoother feed with a slightly slower return. But a better control over the usable range.

I think these are a tough thing to bleed, I was rocking it back and forth to get the air bubbles out and I would work it through the range of motion and that would do a lot, after a while it stopped producing bubbles. One thing I had wondered about though, the manual states to pull the threaded rod in the balancing cylinder out by 2mm, but if I recall it can go more than that. So I assume the further it's retracted and oil filled the more resistance there will be to the landing? I followed the manual's prescription, but couldn't help but think about what that would effect.

I'm using basic hydraulic oil, what kind of heavy oil are you using?

That makes sense, I may end up using a faster rate in softwoods but the hardwoods I use are all within a very normal range of hardness, so I assume once it's dialed in for feed speed I probably won't need to move it much.

That makes sense since some of the pressure is "merely" moving actuators and not "using" air like many other common tools do. Pressure is everything. The Z-Axis assist on my CNC machine works that way. Only needs a really modest air supply as it's just an actuator that doesn't expel air like a nailer does. 40 PSI keeps it happy...and it wants dry air. In your case you do use some air for the blow-out thing, of course, and that's what causes the fluctuation in pressure but it's a small stream.

I'm going to put a metering valve on the chip blow-out to dial it back from full blast to something less and so hopefully consume much less air with it as well. I'm on-board with dry air as well, and after rebuilding this machine no sense in spoiling it. The compressor also has an on board radiator to cool the air. I looked at air compressors every night for about two weeks and finally pulled the trigger on this one, I've been back and forth between wondering if I made the right decision or not and the more I dig into it (to fix things, lol) the more I'm actually pretty impressed by the build quality. It has 3500 hrs on it, so I'll probably have to run through some basic maintenance after few months of running it after fixing these things.

[Mark Hennebury]

I think these are a tough thing to bleed, I was rocking it back and forth to get the air bubbles out and I would work it through the range of motion and that would do a lot, after a while it stopped producing bubbles. One thing I had wondered about though, the manual states to pull the threaded rod in the balancing cylinder out by 2mm, but if I recall it can go more than that. So I assume the further it's retracted and oil filled the more resistance there will be to the landing? I followed the manual's prescription, but couldn't help but think about what that would effect.

Brian,
to bleed these;
you take the feed unit off on the machine and put it on the bench.
Disconnect the yoke that attaches them to the center air cylinder, so that you can move the side oil cylinders individually.
You need a piece of tubing about 3 inches long, copper water pipe, or whatever you have.
A washer
a threaded rod about 3" long i believe it might be 6mm.
A nut for the rod.
Screw the rod in the hole in the balance cylinder.
place the tube over the rod touching the top cap of the balance cylinder. The threaded rod should stick out a bit from the tube.
Place the washer over the rod and on top of the tube.
Screw the nut onto the rod.

Then tighten the nut down 2mm, this pulls the spring loaded piston inside the balance cylinder up, to remove pressure on the oil inside.
Now you can remove the two bleed plugs without oil leaking all over.

Tip the unit upside down in a container to drain out the old oil, unscrew the nut on the balance cylinder, to release the spring loaded piston, emptying the balance cylinder.
Drain all of the oil out.
Get new hydraulic oil , slightly heavier oil than what was in it. You never need the full range of speeds and heavier oil will smooth out the control.

Now you need to get two plastic containers, i use peanut butter jars.
Drill a hole in the bottom of each.the hole should be just big enough to allow you to screw the plastic containers onto the bleed tubes. ( make sure that you clean all of the plastic bits out after drilling.)
Half fill the plastic containers with the new oil, let it fill up the side cylinders.
Open the control valve fully.
Now tighten the nut that you put on the threaded rod that is in the balance piston.
As you screw the nut you will retract the spring loaded piston inside the balance cylinder, filling the cylinder with oil. screw the nut all of the way until it stops, this will retract the piston completely.
Top up the oil in the plastic jars.

Take the plastic container lids and drill a small air hole in the, off to the side.
Screw the lids on the plastic containers.

Now pick up the feed unit and tilt it up and down and round slowly, to make sure you expel all of the air. slowly extend and retract each piston in the oil cylinders, one at a time and both together. move the cylinder around, tilt it as far up and down as you can, making sure that there is always oil enough to cover the bleed tubes, and repeat until no more bubbles are coming from the bleed tubes.
This takes time, longer with thicker oil, warm oil will be a lot easier than cold.
The pistons should be in the fully retracted position at the end of refilling.
Once you are sure that you have no more air in the cylinders.
with the feed unit level on the bench.
Remove the lids.
Take a syringe and remove the oil from the jars.
You should have oil to the top of the bleed tubes.
Place the plugs in the tubes and tighten the nuts, tight.
Unscrew the nut on the threaded rod, remove the washer, tube and threaded rod.
Fasten the yoke to the air cylinder.
Half close the regulator.
Then connect air and cycle.

It all is well it should move nice and smoothly with no jerking, no jumping or gurgling.

If you don't do it this way, you may never get the air out. Trust me on this one.
This is the easiest way that i know how to do it.

You have to move it around quite a bit to get all of the air from the braking cylinders, the balance cylinder and the regulator valve.

[Brian Holcombe]

Thanks, Mark, appreciate the detailed instruction. I used ISO 32, so I’ll switch to ISO 68.

[Mark Hennebury]

Hi Brian,

You might want to go to an ISO 46 and try that first.

[Brian Holcombe]

Will do, Thank you!

[Brian Holcombe]

Awaiting a number of small parts, so wrapping up as much as I can in the interim. Dust pickup in place.

[Jeff Bartley]

Man Brian,

You've taken this machine to 12! What a beautiful machine.

I can't wait to see it make chips!

[Jim Becker]

Dang...that thing is looking even better than the stellar look it already had!

[Brian Holcombe]

Thanks, Gents! Hopefully it works well, it's tough to get something into that spot. I looked at the way centaur does it, and if this doesn't work that well I'll do something similar to that, but I want to to get it cutting wood first.

A have a fitting on the way to cut the air flow to the chisel down if need be, waiting on that.

Working out the hydraulics as per Mark's instructions.

After that I should be ready to go.

[Mark Hennebury]

[QUOTE=Mark Hennebury;2922078]Brian,
to bleed these;

Take a syringe and remove the oil from the jars.
Remove the plastic jars.
You should have oil to the top of the bleed tubes.
Place the plugs in the tubes and tighten the nuts, tight.
Unscrew the nut on the threaded rod, remove the washer, tube and threaded rod.
Fasten the yoke to the air cylinder.
Half close the regulator.
Then connect air and cycle.


Brian, just noticed i forgot mention "remove the plastic jars", I am sure that its obvious, but i just added it for the record.

[Brian Holcombe]

Thanks, Mark!

[Patrick Walsh]

Man that thing is an eyesore Brian....

Pretty freaking nice man.

[Brian Holcombe]

Man that thing is an eyesore Brian....

Pretty freaking nice man.

Hah, thanks Patrick.

[Jim Becker]

Man that thing is an eyesore Brian....

Pretty freaking nice man.

The pictures are nice, but that thing in person is even "more special", Patrick. I know you'd really appreciate it given the attention you bring to your own restoration work.

[Bryan Lisowski]

Really looking good, I bet several people would go to this level, but never use or sell, somehow I doubt Brian falls into either category.