Fein III, Vac hold down, What next

[ed_lang]

I get good results with using screws or my high vacuum dedicated jigs for smaller objects like the cutting boards. I would like to try holding parts and sheets with the Fein III. It would be helpful if I could see pictures of how you hold items.
Lets take the cutting boards for example. I make one size jig and cut one design of board. The high vacuum works great for this. I feel installing screws over and over will cause the hold in the spoilboard to become weak in a short time so vacuum works best here. Now I want to experiment with different designs and sizes. I would like to lay a panel of glued up wood down and then be able to cut a new design. I am happy with using a "skin" and sanding or cutting the parts out.
I have also thought about cutting grooves for T track into my spoilboard and then installing the T track into it. then putting a new MDF spoilboard over the current one and running the same .sbp file that I cut the grooves with into the new spoilboard to expose the T tracks below. This would allow me to use other types of clamps.
Lots of options and I am looking for something that will work for lots of different sizes and shapes. There is no problem slowing down the cut speed to allow me to gain easy holddown if using a lower vacuum but higher volume of air will work.

My solution must be single phase and not be as expensive as the roots blowers and such.

Thanks for links, pictures and details.
Ed

[Brady Watson]

Ed,
You can just add another (or more) Fein vacs to your existing setup. This will not increase vacuum suction, but it will double your CFM. You would basically be looking at 260 CFM @ 7in Hg (I hate saying vac ratings....it's more like 7in Hg @ 0 CFM...)...Anyway, that is an affordable industrial duty single phase deal right there. I have a friend in Pittsburgh that uses 4 Fein T3 units on a 5X10 and it is AWESOME!

Hope that helps!
-B

[evan]

Brady,
Are the Feins all on seperate Zones or are they all pulling together through one manifold?
I'm recieving another Fein tomorrow and have been trying to decide which way would prove most effective.

Thanks

[Brady Watson]

Evan,
They can be used in either configuration. My friend has his setup as 4 separate zones. He did tell me that for one job with a lot of kerfs he used a Y fitting to double the CFM & it worked perfectly. He orginally set it up so that he would have 4 'electric' zones that could be activated at the touch of a button. With 4 Fein T3s he has 520 CFM and 7.x"Hg for around $1200. Seems to make a lot of sense to me.

-Brady

[richards]

You might want to run some tests before deciding to use multiple Fein vacuums. When I close off three of the four zones on my table, the Fein still isn't able to hold a quarter sheet of material (24x48) securely that is being cut into drawer parts (5x21) with a single pass. My actual vacuum is about 5 inches of mercury; however the altitude is about 4,500 ft. (Mike John posted the loss that altitude causes in another thread.) Multiple Feins on one zone might work. Perhaps I need to put a gasket around each of the four zones to isolate them from each other.

Normally I cut full sheets of melamine coated particle board, leaving about 0.030 or so that I trim off with a laminate trimmer. The little Fein has no trouble holding the whole sheet down, but if I try to cut through the sheet, there is too much vacuum loss to hold even 24 x 31 inch side panels securely in place. I'm trying to cut at about 8-ips, 3/8-inch cutter, one pass. I might be doing something wrong, but I have tried to methodically test spoil board thickness, number of zones, cutting speeds, single & two flute cutters, spindle RPM. Multiple passes work fine in most cases as long at the final pass is only 0.025 inch or so. But, making that final pass doubles my cutting time per sheet.

[ed_lang]

I would love to see pictures. Lots of pictures if possible and showing both sides of the spoilboard.

[evan]

Thanks for the info Brady.

Mike- it's that secound pass that I want to avoid.

I have a been using a single Fein T3 with a four zone table, each zone gasketed off from the other, and a edgebanded Trupan spoil board,(I'm at sealevel) for a couple of years now. I'm able to cut cabinet parts down to about 14"x16" in multiple passes unless the ply is seriously warped (in which case I don't want it anyway.) I cut 3/4" material with .375" compresion bit w/ a .02" offset in two passes leaving a .02" skin with a final full depth finishing pass. All at 3-5 ips depending on the type of material. I don't have a spindle, just the Milwaukee (which I like much better than the PC 7518 I use to use.) I don't do a lot of cabinet work because I can't cut in a single pass and it takes too much time. I'd like to do more. I'm hoping the secound Fein T3 will let me pick up my speed a bit and let me cut in a single pass. Although with my set up I've found for the best edge a clean up pass is usualy needed. I hate sanding.
Since just adding a "Y" is the easiest thing to do I'll try that first. If I don't see a marked improvement then I'll redue the plumbing and give each vac it's own 2 zones. I've been wanting to build a new vac table using a non porus material, that will be more stable than the sealed MDF I'm using now. And I'll do that at the same time.
I'll see if I can get some pictures posted after I get back from my trip in two weeks.

Thanks

[richards]

I just added a second Fein III to my Alpha. The vacuum guage shows the same reading (as expected), but there is better hold-down. How much better is impossible to say, but it appears that adding multiple Feins might be an option for those of us who have too little power to run the big blowers.

[gerald_d]

Mike, just for the heck of it, why not try the two Fein's in series? I don't expect it to be better, but it might be interesting....

[richards]

That's how they're connected at the moment. Later today or sometime tomorrow, I hope to have time to run some tests that would show whether the two Fein vacuums can hold drawer-sized parts with just one zone opened.

[gerald_d]

If they are in series then I would've expected a smallish increase on the vacuum gauge?

[richards]

Sorry, no increase. In fact, if only one vacuum is on, there is a slight decrease (about 1/2-inch of mercury). I suppose that decrease might be blamed on air flowing through the vacuum that is turned off instead of flowing through the spoil board.

As I understand it, if either vacuum can pull 5-inches of mercury when connected only to the vacuum guage, then both vacuums would still be able to pull only 5-inches of mercury, but at twice the air flow. In a more sophisticated setup, it might be wise to install a check-valve in-line with each vacuum to eliminate the stronger vacuum from sucking through the weaker vacuum.

[gerald_d]

Mike, I think your concept of series is my concept of parallel. Putting multiple vacuums into a plenum, manifold or Y-piece puts all their inlets at the same pressure zone, and all their outlets at atmospheric. (like voltage rails at the ends of parallel resistors).

By series I mean that you play with letting the second Fein suck out of the exhaust of the first one.

[richards]

Gerald, you're right, I was thinking of the difference of having each vacuum plumbed to its own zone as opposed to be connected in parallel to all zones.

Unfortunately, the Fein III model doesn't have a conventional inlet and outlet. The exhaust air escapes all the way around the motor housing instead of flowing to an outlet/hose connection. Therefore, connecting the vacuums in series will be difficult.

[gerald_d]

Yeah, a diffused outlet like that is one of the ways in which it gets its noise down.

[Brady Watson]

You have to be careful...some vacuum motors allow you to set them up in series and others do not. Unless you are spec'ing out a new stand alone motor itself, I would imagine that finding out if it is possibile to run in series would be difficult to verify.

-B