What is the model of this pump?
Gast DOA-P701-AA

Isn't this an air compressor and not a vacuum pump?
Yes this is a compressed air pump, however it can be used for vacuum and it perform as well or better than its relative - the DOA-V722-AA model. We've opted for this unit to help keep our prices as low as possible without sacrificing durability or performance.

Does the pump come with rubber screw-on feet?
There are small rubber pads on the bottom of this pump. I don't offer the rubber feet as they are exceptionally expensive and offer little value. I'm not sure where you could order these feet other than from Gast Manufacturing or one of their distributors. This pump has so little vibration that the rubber feet seem more of a cosmetic item than a functional one.

Can this pump be used for vacuum chucking?
There is no safe way to answer this question. More information needs to be provided. You would need to know three things...

1. What is the surface area where the chuck attaches to the project?
2. Is the project material porous? (some species of wood are very porous)
3. How much weight will be held on the chuck at turning speed?

With these bits of information, you can calculate a number that will help you determine if the pump is safe to use for chucking. Continue on to the next question.

How much clamping force will the pump create for vacuum chucking?
This is based on a calculation using the maximum sustainable vacuum level and the surface area where the project is attached to the chuck. A smaller attachment area means less clamping/chucking force. A large industrial pump capable of pulling a very high vacuum may not be suitable for chucking if the vacuum surface area of the project is small. You have to calculate the vacuum surface area on your project first. Then determine what amount of vacuum you are capable of applying to the project. With this information, you can determine the total clamping force on the project and consider whether or not it is enough to safely hold your project while it is being turned. Here is the method for calculating the clamping force.

1. Determine the surface area of the vacuum attachment point. In most cases, the vacuum chuck will be circular so use Pi (roughly 3.14) to determine this number. The formula starts by taking the diameter and dividing by two. This gives you the radius. Then multiply the radius by 3.14 and then multiply it again by the radius. Let's use a chuck diameter of 6" and determine the surface area. Divide 6 by 2. That makes 3 so then multiply 3 times 3.14 (Pi), then multiply that again by 3.
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   6 ÷ 2 = 3
   3 x 3.14 = 9.42
   3 x 9.42 = 28.26
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   So here we have 28.26 square inches in a 6" diameter chucking surface.
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2. Determine the maximum sustainable vacuum level that you can reach with your project piece attached to the vacuum chuck simply by placing it on the chuck and turning on your vacuum pump. A non-porous material that is chucked to your lathe will typically achieve the same level of maximum vacuum that your pump is capable of achieving. In other words, the project material itself allows no loss of vacuum therefor the pump will achieve its best available vacuum.
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   In the following example let's assume that the project material is non-porous and that the pump can generate 25" of Hg. For every inch of Hg vacuum, you get .49 lbs per square inch of pressure. Multiply .49 by the vacuum level that the pump can create.
   
   .49 x 25 = 12.25 (this is how much pressure in pounds that you are getting per square inch)
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3. Multiply 28.26 x 12.25 to get 346.19 lbs of force holding your project to the lathe.
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4. Now only you can decide if that is enough chucking force to safely hold your project.

What if the chucking project is porous? How do I determine if this pump is suitable?
Unfortunately, there is no way to determine this without actually placing the project on a vacuum chuck. You would need to determine the actual maximum sustainable vacuum and this will vary across each project you try out depending on the size and porosity of the material.

What pump do you recommend for vacuum chucking?
I can only suggest one thing... the bigger, the better. Several of our customers are using 3 CFM vacuum sources for chucking but most are opting for 5 CFM vacuum sources.