What's your Gast 0523 pressure reading?

[Matt Haus]

Just got my vacuum chuck setup and I am pulling 21 inches at the motor. Anyone get more than that with their pump? It's a used pump and I am just wondering if the vanes need replacing or will 21 be just fine. Gast tech guy said it should get 26 inches max.

Thanks.

[Matt Haus]

Come on now, I know a few of you have vacuum pumps set up. I went ahead and ordered a new kit. We will see if it makes a difference.

[Ken Garlock]

I don't have a vacuum pump, but from what I have observed, 24" or better should be achievable in a short time.

I know you were careful in assembling your system, but I would go over all the joints with a fine tooth comb. I would start by plugging/sealing off the vacuum line at the point it enters the veneer bag and then crank up the pump and read the vacuum gauge. If you don't have a problem (ie 26"), you obviously have a bag problem. If you still have a low vacuum, start moving back, inspecting joint by joint, until you get to the pump. To check the pump, put a short piece of hose from the pump to the gauge and read what the pump will do by itself. Another thought, do you have confidence in your vacuum gauge?

Happy hunting....

[Bill Boehme]

Unless you are using an expensive gauge with traceable calibration, measurement tolerances can be part or the reason for a low reading. Another reason is that the 26 in-Hg spec number is for a blocked port vacuum on a brand new pump and if your measurement is with a rotary adapter, vacuum chuck, and bowl in place, you will get a lower reading. A reading of 21 in-Hg isn't bad and since you have a used pump, it is to be expected. When to install a rebuild kit is up to you. I suppose that you do know that you shouldn't use full vacuum in most situations anyway. Calculate the needed vacuum based on the holding force that you want for the wall thickness of the bowl that you have mounted.

Bill

[Matt Haus]

The pull with the gauge right at the motor is 21 inches with nothing in between and is consistent up to the chuck. I don't know about the guage because it is new. I don't really want to purchase another.

I just wanted to know what to expect with this model. If everyone is getting 26 inches or close to that, then it's a problem with my pump. If everyone is getting around what I am getting then I won't worry. I have a kit coming, I will just replace those vanes. I used it last night and with 21, I got a good hold and was able to finish the bottoms of 2 pieces I hadn't gotten to. It seems to cut ok and felt pretty stabil.


edit - thanks Bill. I saw your post right after I posted this. All and all, I am pretty happy with the setup.

[Jim Becker]

I have gotten as high as 25hg on my 0523, but it's a variable thing...depends on the particular piece I'm turning. And remember, sometimes you need to dial it down to avoid damaging the turning, especially for finishing cuts.

[Christopher K. Hartley]

Matt, If the guage is on the in port of the pump then cover the exhaust or out port with your finger and see if the guage rises at all. I noticed when I put my muffler on my out port my vacuum increased by about a point and a half. Also, are you running 220V or using the 110V adapter? It may be possible that is part of the issue, but Bill could better make that call. Mine is pulling right at 24 to 25. with all my stuff connected except the lathe. Since talking to you I did remove the second filter and add another shutoff valve so I can follow the instructions for proper shutdown.:)

[Travis Stinson]

I wouldn't worry about it too much right now. I adjust mine with a bleeder valve to down around 15hg for most pieces.

[Jim Ketron]

I'm with Travis I usually run mine at 18 In or less remember its all in the size of the piece your working on and the size of your drum chuck. (Volume makes all the difference) if you are just finishing off the bottom of pieces a 4" drum chuck should do most anything you will need. I use a 6" drum for larger pieces and getting ready to make an 8" one for the whopper size stuff.

[Matt Haus]

Also, are you running 220V or using the 110V adapter? :)

I am running 220. I may try what you stated and see if it make a difference.

[Bill Boehme]

The pull with the gauge right at the motor is 21 inches with nothing in between and is consistent up to the chuck......

When you say "nothing in between", that is not actually true if you have the rotary adapter in the line. Even a very minute amount of leakage through the bearings in the rotary adapter will have a significant effect on the reading. Screw the gauge directly into the vacuum port on the pump itself with sealant on the threads to see what your true "blocked port" vacuum reading is. Depending on the diameter of your vacuum chuck, you can sometimes safely use a vacuum as low as 10 in-Hg.

Bill

[Ken Garlock]

If I had read your post correctly Matt, I would have just moved on since I don't know Jack Snot about vacuum chucks. Oh well, I got my exercise by jumping to conclusions.

Sorry.:o

[Matt Haus]

When you say "nothing in between", that is not actually true if you have the rotary adapter in the line.
Bill


Bill,

That's what I meant to say. the gauge is only hooked to the vacuum port right at the pump. Nothing in between means the other lines and set up was omitted.

Now, with everything hooked up, I still get the same reading as with the gauge at the pump. I have a new vane set coming, so I will keep all updated so that in future reference, it may help someone.

[Matt Haus]

I changed the vanes out today on the Gast 0523. The old vanes were worn in the middle of the carbon and you could see that they were thinner in the middle. The end were also not seating well against the cylinder wall.

After replacing the vanes, the vacuum went up to 25.5 inches of mercury from 15. Alls well that ends well.