More questions!! Vacuum table necessary?

[dray]

I do mostly cabinetry which are all large pieces or fairly large pieces. I have been tacking the sheet goods to my table in 2-3 spots w 1 1/2" 18g brad nails then cutting in 2 passes and havent had any problems so far.

But for the "play" or fun stuff Ive been doing they are all small pieces will a 2-3 fein vacuum system hold small pieces?

Any other cabinet guys out there using a 2-3 fein system? Is it worth the extra noise?
Do you have to slow down when cutting?

currently Im cutting 400 inches per minute in 2 passes through 3/4 mdf with a 1/4 end mill.

Thx!!

[beacon14]

How small?

I don't know of anyone who has gone with a vac table and regretted it. The 2 Fein vac system will hold just about anything if you approach it properly - "onion skin", tabs, proper cutting order, etc.

[dray]

Small stuff maybe 3" square.

[bleeth]

Danny: It depends on the size of the parts you are starting with. If you are talking about cutting a bunch of "bulls eyes" out of a board you will end up leaving a skin, and due to the nature of boards (twists and cups), most people use a clamping system or screws for that. If you are starting with small pieces and carving them, then the "puck" system with your high vacuum/low volume system works best from what I hear. Twin Feins will hold down your full sheets while you cut your cab parts out and it takes a heck of a lot less time to turn them on and off then it does to run around the table putting in and removing screws. If I was going to do a whole lot of carving on small pieces, I would cut a mask to cover my vacuum zone and drop my little parts into it to carve the relief into them. The more details you go into of your needs the more specific the answer can be. Feel free to e-mail me direct if you don't wish to post details. It's the least I can do to thank you for the "bugs"

Dave

[richards]

Danny, 9-square inches is pretty small, even for a GAST type vacuum that pulls 20+ inches of mercury. Without tabs, I know that I couldn't cut something like that with my Fein vacuums (2 of them) and the spoil board method. Even with my GAST vacuum using a puck with All*Star tape, I don't think that it would hold.

You would lose at least 1/2-inch around the parimeter due to the tape, so you'd have about 6.25 sq. inches to deal with. Six square inches at 20-inches of mercury is about 60 lbs of holding force. Maybe with light cuts it might work, but I haven't been able to do it with my system. The smallest pieces that I cut with confidence using the GAST and pucks are about 4x5 inches, which gives about 15 sq. inches with the tape and about 150 lbs of hold down.

[dray]

Thanks guys, that helps alot..

For now I know what Im laying out and basically where it is. So for now at least Ill keep popping in a couple 18 guage 1 1/2" brad nails.

My gun is always right at the cnc because we pull parts directly off and have 2 4x8x36" rolling tables we assemble the cabinets on that are always right next to the cnc.

THX again

[tuck]

Danny Ray, you are a cabinet maker and I'm a sign maker, but I've had my Bot for going on 6 years now without a vacuum table and have no intentions to get/build one. I haven't come across anything yet that I wasn't able to cut/mill/produce by simply screwing the material down or using clamps. In some instances for small cut-outs in tough material, I'll use tabs. I think your using brad nails is a great idea because they won't ruin a bit, where a screw will.

Also, for thicker material like 3/4" MDF, I use a 1/4" spiral down bit. It packs the cuttings into the kerf and keeps the piece from moving during final cut-out.

I can understand why some guys swear by their vacuum systems, but they are a lot of work and expense to build/buy, and noisy too. I say, "If'n it ain't broke, don't fix it!"

[jhicks]

Mark, I was just like you for over 3 years and clamped, screwed, fenced, or stapled parts all the time.
Now that i've had a vac table for 6 months, I would NEVER go back. Guess you know it when you see it but as usual, whatever works for you, is what you have to decide is the best.
I just know I resisted and now wonder why I didn't set it up sooner.

[donchapman]

My experience is like Jerry's, only 7 years before I switched, and all I have in my one small Fein vac hold down is about $300.00, so cost is not a big deal.

[jhicks]

I think the saying is
"Once you go Vac you never go back"

[tuck]

I must confess, I was cutting some small aluminum and pvc pieces today that were giving me fits and I thought; "Dang, maybe I should build a vac system."

On the other hand, I got through it and 90% of my particular kind of work is larger 2.5D HDU signs. It's just too easy to screw the sheets down, taking care that the screws won't be in the way of the bit as it cuts. All I use is two or three screws and I've yet to have a problem.

I'm not high production. I may cut only 6-8 large signs a month, if that. If I was needing to get the next sheet cutting as soon as I got the prior sheet off the table and it was like that everyday all day, I would certainly get serious about a vac.

I did install a vacuum for dust collection, so give me some credit! :-)

[dray]

Well after hearing from Jerry and Don I think I may buy 3 feins for $900 you cant go wrong I guess. I cant see paying the $10k that shopbot wants for their vacuum setup but maybe ill give the feins a shot.

I said the same thing to myself after cutting out my first cabinets on my cnc "I cant believe I wasnt doing this for the last 10 years"

thx

[donchapman]

Mark: There's certainly nothing wrong with using screws if it works well for you, which it seems to be doing. I did the same thing for 7 years. But I also do a lot of HDU signs (as well as routing a lot of MDF, MDO, other plywoods, and solid woods) and here are some ways vac hold down sometimes works better than screws for me. I can do a 2-faced sign in thick enough material with no screw holes in either face. The vac holds all pieces very flat to the table so there's no problem with bowed piece sticking up somewhere and needing a screw in the face to keep depth of cut uniform throughout the sign, which can be especially important if it's v-carve routed. Even if there is room for screws in the scrap outside the finished sign border, with vac hold down I don't have to do tabs or be concerned with the sign moving on the final cut-out pass which releases the sign from the screwed down scrap. My table doesn't end up with dozens or hundreds of screw holes and dimples after a few weeks routing. I use to do a lot of securing the material with screws from under and through the table and into the back of the material and I don't miss doing that contortionist act at all, and don't miss having to be sure not to put too long or short a screw in, or torque it too much, or inadvertently push up the material, or forget to remove the last screw or two and have to go back under. The back of the material remains undamaged by screw holes, so if I make a mistake in the front of the material I can flip it over and use the undamaged back.

Now I just slide the material onto my table, flip on my Fein, rout, turn off the Fein, and remove the sign or other project. My new way is not "right" and the old way "wrong". I just find it fast, convenient, and pleasant using my inexpensive vac hold down and have used no screws in routing dozens of projects from as big as 4'x8' to as small as 3"x15" during the past 4 months.
I did use carpet tape to hold some 3"x10" material from which I routed some small bridge and neck details for a uke and mandolin.

[elcruisr]

There are many different approaches and none of them wrong unless they create a bottleneck in production. I use a 15hp regenerative blower and there are times I wish I had even more! That said however, I run pretty large parts counts. I could not be profitable at what I do if I had to screw, clamp or tape down sheets! The difference in cycle times would be huge.

[Brady Watson]

As most of the seasoned botters know, there's no silver-bullet/one system fits all hold-down system. If you do a lot of different types of cutting, you will have to employ many different methods to get the job done. I bucked the vacuum concept for a long time...using screws and carpet tape. After some experimentation, I was blown away by how simple vacuum hold-down can be, as well as flexible.

I like to keep all of my hold-down options open. I didn't buy a big vac because I don't cut big sheets day in and day out. I still use screws and carpet tape for certain jobs, where vacuum doesn't make sense, but most of the time I use a single Fein TIII to hold down everything from full sheets to thousands of parts that are under 1" square. It boils down to how efficiently you can use the vacuum, and if it's a good match for the job. Many parts that I cut out can't be held down with tape due to the amount of labor needed to clean off residue, and can't be held down with screws because it would be in the face of the finished part(s).

The BradyVac concept allows you to make a removeable (or several different sized) vacuum grid/bleeder combo boards that you can add or remove from your spoilboard. This gives you flexibility to screw things down, use tape or hold things down with vacuum. It gives you a lot of flexibility and you don't have to be married to one particular system.

Just to focus a little closer on the removeable vacuum plenum concept, one size plenum doesn't fit all. You can use zones like a traditional system OR make several purpose-built plenums that make the most of the vacuum for the parts you are cutting. I have one big 4X8, a 4X4, a 24X32, 24X48 and a 6X96 for long parts. They are sized to make the most of one Fein vac. Combined with vacuum masking/gasketing, the efficiency of this system goes up even more, allowing you to really squeeze the most out of your vac source.

While some many think that protyping your own systems and doing actual experiementation in a waste of time, it really pays off when a difficult to cut job comes down the pike. Try out new things & ideas...you just may suprise yourself, and give yourself an edge over the competition...

-B

[cjohnson]

I have a turbo III just waiting to be hooked up. My table is rather large (5x10) and I really dont know how many grids to make, what size, or anything. I'm hoping that this all comes to me soon but I just haven't cut enough of anything to determine what i need. Most of the stuff i make is one off and is less than 2'x2'. I never purchase 5x10 mdf because it weighs too much, is a pain to move around, and storing it is a nighmare. 4x8 is a bit more manageable so I tend to get it from a local store and make whatever i need from it. So I guess i need to plan around a 4x8 sheet.

While the Fein does has some limitations when it comes to inches of mercury, I have been wondering about alternatives or combinations. I would like to build the best of both worlds. I can't fully explain the concept yet except that it would employ both the FEIN and also a higher vacuum source (more inches of mercury). Maybe a ex-250gal propane tank outside piped in through check valves that combines with the fein that also has check valves. Probally won't work but it has been a round about thought.

cj

[Brady Watson]

CJ,
The Hi-lo vac concept is something that I have explored. It is excellent for smaller areas, but will do nothing for large areas where you cut all the way thru the parts, breaking vacuum. You'll still be at the limitations of the Fein and how much leakage (CFM) it can tolerate while still holding parts.

-B