[adam_m]

Just curious if anyone has ever tried using one of these small vane pumps in a vacuum hold down type setup...

These are "oil-less" design pumps which produce clean air and require no lubrication. Please see all the pics. Approx Performance Specs: 145 Watt, 0.12 - 0.15 horsepower, 10-15 psi pressure, 22-23"hg vacuum.

2-23hg... would it work?

Gast USA 24V Brushless Rotary Vane Air Pump/Compressor 24 volt DC *** Special! | eBay

Adam,

[JerryBurks]

I use it all the time and really like it. and I know I know other folks use it as well. It is however only suited for smaller parts (let's say min 4 square inches, max 500 square inches) of solid wood or plywood and it must be well gasketed, no cracks in the wood and forget mdf since it is too porous.
It is not possible to cut larger sheets on a spoilboard. for that you need a high volume blower with 5 or 10hp or more.

[adam_m]

Interesting...

I'm gathering that the size of the piece to be held plays a major part in the amount of volume and HG needed.

Assuming a 24"x24" area what type of continuous HG/volume do you think is needed?

I also noticed this type of Vane pump that contains essentially air pressure and vacuum (Gast 1531-107B-G557X Rotary Vane Vacuum Pump and Compressor **BARELY USED!!" | eBay) any thoughts on its performance? Maybe killing 2 birds with one stone...

Adam,

[JerryBurks]

Interesting...

I'm gathering that the size of the piece to be held plays a major part in the amount of volume and HG needed.

Assuming a 24"x24" area what type of continuous HG/volume do you think is needed?

I also noticed this type of Vane pump that contains essentially air pressure and vacuum (Gast 1531-107B-G557X Rotary Vane Vacuum Pump and Compressor **BARELY USED!!" | eBay) any thoughts on its performance? Maybe killing 2 birds with one stone...

Adam,

Sorry, I just looked up the pumps you mentioned...not sure about the vane version. I do have a GAST pump as well as a Thompson pump but these are of the dual rocker piston type (oil-less), also purchased refurbished on eBay for about $150.
As for the size, the larger you go, the more leakage you will have to deal with. On the other hand, the larger surface will give you more holding force even if the vacuum drops. You will need a vacuum gage to see if the vacuum keeps dropping after turning it on and to make it practical you need a vacuum reservoir, maybe 2-3 gallons, to allow for the initial suck-down while the gaskets are not fully sealing.

But otherwise, I use the vacuum pods maybe 80% of the time since it is so quick and easy without clamps, screws, fences, tabs etc. and saves material since you can go to the actual material boundary. Only reason to use other methods is if the parts are too small, have too many holes or the wood has cracks and knots.

I have a full-size 36x48" extrusion t-slot table but converted (sealed) 6 of the slots to vacuum conduits with a taped-on cover of thin aluminum flashing. I can tap that anywhere by punching a small hole into the aluminum (can be sealed with tape again) and putting a disposable "pod" with gaskets below and above on that hole. Difficult to explain but I can post a picture if interested.

[underthetire]

We have all types of gast pumps at work. The vane ones are SUPER loud and run REALLY hot, but they do pull more volume per size than the piston or diaphragm types.

Sent from my SM-T813 using Tapatalk

[ger21]

What's the CFM rating on that little pump? I have a 3CFM Gast rotary vane pump, and it's noticeably better than a 1.5CFM pump I had. At least with wood, where the vacuum leaks through the material.

[sajurcaju]

Until I can afford a vacuum pump I'm using my shop vac. It works fine for things 2' on a side. For 1' square I need to reduce the cutting speed/depth i.e. the force applied to the work.
Plenty of cfm, not as much vacuum. I use rubber roofing material (EPDM) for gaskets since I have a lot of it and it is easy to cut.

Steve

[adam_m]

Jerry,

Here are the stats on that vane pump, the larger of the 2.

Pump Operating Type: Compressor & Vacuum Pump Combination
Power Source: Electrical
Lubrication Type: Oil Free
Horsepower: 1/10 hp
Motor Phase: 1
Supply Voltage: 115 V
Frequency: 50/60 Hz
Maximum Continuous Pressure: 15 psi
Maximum Vacuum: 335 Mbar
Maximum Vacuum Mode Flow Rate: 1.25 (50 Hz) cfm, 1.5 (60 Hz) cfm
Inlet Port Size: 1/8 in
Outlet Port Size: 1/8 in
Overall Length: 227.8 mm
Overall Width: 106.4 mm

I can't find any specs on the smaller unit, model #2032-V110-G635 except for the following:

Gast 2032-V110-G635 24V Brushless Rotary Air Pump/Compressor 24 volt DC 6.1 AMP .12HP 3500RPM

, its not on their website that I can see.

Jerry, your using this particular pump the 24volt deal? How noisy is it?

Gast USA 24V Brushless Rotary Vane Air Pump/Compressor 24 volt DC *** Special! | eBay

I'm guessing a shop vac might work for my situation but I would need to build a box since my table doesn't allow for access below, or at least it would be difficult to do.

I'm thinking the "Hockey puck" scenario might be my best approach to get started and test with. What type of CFM and HG would those require and are they calculated by the piece?

Adam,

[pippin88]

Until I can afford a vacuum pump I'm using my shop vac. It works fine for things 2' on a side. For 1' square I need to reduce the cutting speed/depth i.e. the force applied to the work.
Plenty of cfm, not as much vacuum. I use rubber roofing material (EPDM) for gaskets since I have a lot of it and it is easy to cut.

Steve

You may already do this, but a combination of vacuum and clamp holding works great. Clamps or blocks on the edges of the piece stop lateral movement and the vacuum stops lifting and sucks the piece flat.

[sajurcaju]

Great suggestion pippin, I'll try it.

Steve

[adam_m]

We'll I bought one of the small pumps and I'll see what it has in store for small part holding..

Adam,

[Donatello Tam]

I'm looking for something similar too. Could anyone tell me this is a vacuum pump or compressor?
I wonder if it's for sucking air or blowing air. Thank you.

Don

[zeeflyboy]

Two sides of the same coin, if it blows it must suck and vice versa... it is both a compressor and a vacuum pump.

[Donatello Tam]

Two sides of the same coin, if it blows it must suck and vice versa... it is both a compressor and a vacuum pump.

Thanks, man. Simple and direct answer.

[wizard]

Just curious if anyone has ever tried using one of these small vane pumps in a vacuum hold down type setup...

Nope! But the first thing that come sot mind is why would you buy a 24 VDC pump. GAST makes many designs that can plug right into the wall outlet which are simple to use.

2-23hg... would it work?

When it come s to holding something it really comes down to how much leakage will you be expecting. You can get a hold down with a very little volume but it takes a long time to pump out the air. Once the air is pumped out you get the same holding power as with any other pump. The problem comes with leakage which little pumps can't deal with.

Adam,

If it was me the first thing I would do is to look for a 110 VAC pump preferably with a much higher volume capability. Running on regular line voltage solves the power problem and a larger pump will better deal with all the potential leakages you might have.

In automation we use all sort of vacuum pumps from venturi types up to huge pumps used to pump down vacuum coating chambers. In the end it is the volume capability of the pump that generally makes the difference (excluding very high vacuum applications) as the volume capability impacts time to grip a part or empty a chamber. Remember you literally are pumping air out of whatever you are trying to pull a vacuum on. Once the air is pumped out you then need to worry about any leakage, if the leakage is so great the the pump can't keep the pressure low you will release your parts. This is where vacuum chucking can be a problem if you are cutting completely through the stock as you can have so much leakage the part send up sliding around. There are ways to deal with this so pump volume is only part of the solution and frankly can only handle a small amount of leakage.

Honestly I wouldn't bother with the pump at all. If you want a nice GAST vane type pump get a much larger unit.

[wizard]

Interesting...

I'm gathering that the size of the piece to be held plays a major part in the amount of volume and HG needed.

Volume is of interest in two ways. One the initial pump down time to empty a chamber of air and two the ability to overcome leakage into that chamber. The actual pump down pressure isn't as big of a deal as some make it out to be as most pumps can draw a pretty good vacuum. In the end all you have to work with is atmospheric air pressure, the vacuum pump dines't actually create pressure that is the air sitting on top of your part. In effect you pump the air out from under the part and the air on top creates the clamping pressure.

Assuming a 24"x24" area what type of continuous HG/volume do you think is needed?

Sadly there are many variables so the only honest answer is that it depends. In the machine tool industry guys are using little venturi vacuum generators to clamp parts to a milling machine sub table. If the box under your parts is real leaky you may need 1 or 2 horse powers worth of pumping capability. If cutting through the parts results in heavy leakage you might not have enough capability even then. This is why guys go to various extents to try to control leakage on their tables.

I also noticed this type of Vane pump that contains essentially air pressure and vacuum (Gast 1531-107B-G557X Rotary Vane Vacuum Pump and Compressor **BARELY USED!!" | eBay) any thoughts on its performance? Maybe killing 2 birds with one stone...

Adam,

Well I'm not sure I'd call them compressors. In any event you don't want restrictions on your pumps output.

In the end you just can't say which pump will be right (it is mostly an issue of volume) until you understand you your table vacuum box will be constructed and how you will be machining part son the vacuum table. What you will need performance wise can vary widely. One usage might get by with a venturi generator and right next to that machine you might need a Roots blower.

[wizard]

Adam;

Based on the CFM spec I wouldn't bother with that pump unless you have a really tight vacuum box with little to no leakage.

Jerry,

Here are the stats on that vane pump, the larger of the 2.



I can't find any specs on the smaller unit, model #2032-V110-G635 except for the following: , its not on their website that I can see.

Jerry, your using this particular pump the 24volt deal? How noisy is it?



I'm guessing a shop vac might work for my situation but I would need to build a box since my table doesn't allow for access below, or at least it would be difficult to do.

I'm thinking the "Hockey puck" scenario might be my best approach to get started and test with. What type of CFM and HG would those require and are they calculated by the piece?

Adam,