Overhead dust pick up are problems.....

[Jim O'Dell]

Some of you may know that I've been working on the overhead dust pick up for my table saw. I have finished the second version today, and I'm having the same problem. I have tried the mount to the side (ceiling mount) and to the rear. But there is too much play side to side on the pick up housing. The wood doesn't want to slide under the pick up. Possibly my curve at the front is too abrupt, and needs to slant more to to ride up over the wood. But the whole housing moving side to side bothers me a lot. How stable are the commercial units that mount to the ceiling or the back right of the extension table? Any ideas on how to stabilize this set up?
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The first picture shows the pick up, and hinging mechanism. I used the Wood Central Blade Guard article to go by. It is almost an exact copy...very minor changes in lengths beyond the pivot points, except for the extension from the attaching point to the dust shroud. This had to be lengthened because of where my TS has to sit in relation to the mounting point for the arm. (Lights directly above the TS) I'm sure this introduces some movement, but I'm surprised at how much I'm getting...3" either side of center, maybe a tad more. The second picture shows the mount at the ceiling that allows me to move the whole unit up and out of the way. It can also be taken out or pivoted in 90 degree increments to be further out of the way. Picture 3 shows the mechanism minus the dust pick up. Picture 4 shows the unit recessed as far as it will go up. (I'm limited by the shallow attic space or it could go all the way to the ceiling.)
The problem again is side to side movement as you are at the front of the TS. I hope someone has an idea. I'd hate to think about scraping 2 weekends worth of work, not to mention the steel and aluminum. http://familywoodworking.org/forums/images/smilies/eek.gif THANKS!! Jim.

[Norman Pyles]

I'm going to be making one of these in the near future, so I am really interested to see how this goes. Which part is moving, causing the side play?

[Jim O'Dell]

It's the pick up shroud that is moving. But that is at the end of a 15.5" piece of 1" box aluminum tube. The more I sit here and think about this, I think the movement is normal, but because of the extra pipe I have to the pick up, it is being exagerated to the point that it makes me nervous. :rolleyes:
I think I can take my ceiling mount and build a 30 degree angle block to mount it to, so that the down pipe will end up at the dust pick up shroud. This will get rid of the 15.5" piece of alum square tube, and maybe it will cut down on some of the movement. Hopefully I won't have to go get another piece of 3/4" steel tubing! I'll post back when I do that.
I still welcome any and all ideas!! Jim.

[David Micalizzi]

Jim I built a copy of the Biesmeyer and I have very little play side to side, but there is some less than 3/8”. You have a lot of leverage happening because of the distance of your main vertical support to your blade guard. You could try to run a vertical piece right up from the guard housing and lengthen the pivot arms so they connect directly to the guard housing and the vertical main support. This would eliminate the single point of attachment that is causing I’m sure most of the play. Also, it may be possible to straddle the light fixture with something ridged like 2”angle iron, even plywood and shorten up the distance from your vertical support and the blade guard. I think the material you are using for the span you have is just not up to the task. I’ll give you an Idea of what I used to build mine. I used 2” square tubing for the main support. 1” square tubing for the vertical supports posts and 1” x 1/8” steel flat stock for the pivot arms and have no movement or flexing issues. Here are some pictures. Hope this helps.

[Jim Kountz]

Jim , I built the Woodcentral unit myself and I went out and measured the play in mine after reading your post. I have about an 1/8" either direction when applying moderate pressure. If I really grab it and pull it will deflect about 3/4' at the most. I do have a couple of key differences. One I have two mounting points vertically. I didnt have a finished ceiling when I put mine in (oh who am I kidding I still dont have a finished ceiling:D )and I mounted two 2x4's between the ceiling joists, one flush with the subfloor upstairs and one just fastened across two of the joists. This gave me the ability to mount it with two bolts approx 10" apart or the width of the ceiling joists/rafters. The second difference is the extension. I doubt that its helping your cause at all. Seems like that could be a big culprit right there. If it would help I could snap a couple of shots of mine and post for you.

Jim

[Tom Maple]

Jim,
My first thought after looking at you pictures is the entire mechanism has a "delicate" look to it. Small tubing and long lengths. If you figure the distance from the attachment point at the ceiling down to the dust shroud, you're looking at a good four feet. With all the pivot points along that distance there's bound to be movement, unless each joint is sleeved and bushed. I would start by putting a diagonel support from the ceiling to just above the top pivot to stiffen up the vertical leg. It may also be necessary to go with a larger cross section of tubing. This would reduce the side to side movement at each pivot point.
I'm not trying to be critical, I'm planning on doing the same type of collector and appreciate being able to learn from your experience.
Tom

[Jim O'Dell]

David, nice set up! I may in the end have to go to a table mount, but I'll explore my options before I go that far.
I did go out during half time and re-mounted the pivoting section to the upright pole. It was done with rivits and there was some space in between the pieces. So I drilled out all 10 rivits, filed (that doesn't look right) the burs and reinstalled with bolts. It seems a little better. And the wiggle at the end of the pivoting section is minimal, so it is being telegraphed at the end of the 15.5" piece making the movement very exagerated.
Well, I missed the Eagles scoring 3 and the Cowboys scoring 7, so I guess I took a little longer than half time to do my rework.:D Jim.

[Alan Schaffter]

Your rig has too long of moment arms. The vertical support needs side braces to keep from swaying. The parallel mechanism is too flimsy and provides too much of a moment arm to stay straight and not rotate.

What I am going to do:

1. Use a three point support from the ceiling
2. Replace the parallel mechanism with a flat, 3"-4" wide by 8" long plexi panel that hinges at the back about 6" above the table.
3. The plexi panel with hole for dust port can be either latched up out of the way or lowered down where it stops parallel to the table.
4. A "dust skirt" like the spray guards on a truck is attached to the periphery of the plexi panel to contain the dust and help channel it into the dust port.

This rig contains the dust, easily conforms to various thicknesses of wood, is mechanically simple, and folds up out of the way. Boards of any thickness can easily slide under it. It provides only minimal blade protection- not a concern for me.

[Jim O'Dell]

Tom and Alan, is this a implementation of your ideas? If so, thanks!! It works great. No wobble, well maybe a 1/4" each way. But it's WAY SOLID!! And it still retracts up into the ceiling to get partially out of the way.
Now I need to get a couple star washers to hold the knob bolts when I tighten them up, and a couple nuts with the nylon inserts to lock the bolts down on the upper pivot mounts. Oh, and bolt the dust pick up head to the arm.
Thanks everyone! Jim.


Edit: And the crowds are shouting, is what a good implementation of these ideas???:o:o:o:o 2 hours later and I remember to add the pictures. Nothing wrong with me!
First shot is in the down position. 75037
Second shot is in the retracted position. 75038 Jim.

[Tom Maple]

Jim,
Yep, that should do it. The diagonal supports are what I was thinking of. You made it much more sophisticated than I could have. My solution would have been to start slapping steel together and welding up something stiff and heavy. Your solution is much more elegant. The slotted supports are a nice way of maintaing your raise/lower capability. Nice job.
Tom

[Jim O'Dell]

Tom, my first 2 drawings were of some more steel tubing, with other steel tubing sliding through them, but I couldn't figure out how to anchor them down in a particular position, nor how to put 2 square tubes together with a pivot. I started thinking about the tilt up lid supports for, say a cedar chest. Said to myself, "Self, you'll never find steel with a long slot in it." That's when I thought of using wood. So it didn't come to me quickly, but it does work nicely. Again, thanks for the idea to get me thinking. Jim.

[Chris Barnett]

Probably a shot off to the left, but any chance in adding simple high intensity task lighting lamps directly to your exhaust fixture so that the overhead is available to suit your support scheme? Or overhead task lighting oblique and each side to work area?

[Jim O'Dell]

I guess it's too late, but my mind is not following your question. I have a feeling there is a joke in here somewhere, but I'm not seeing it. :confused: :D:D Or are you wanting a better picture of the contraption? Jim.

[Dan Forman]

Maybe too late, but here is how I did mine.

http://i98.photobucket.com/albums/l279/T-Caster/Woodwork/P1010573.jpg

http://i98.photobucket.com/albums/l279/T-Caster/Woodwork/P1010576.jpg

Limitations are that it doesn't lift over the work piece as it goes through, just stays where it's put. It has to be moved laterally if need be to allow for ripping narrow strips, or back to crosscutting from ripping narrow strips. It swings completely out of the way when needed, and the hose can be used to make it stay put in that position (not pictured). Sometimes it seems a bit of a hassle, and it can get interesting when small cutoff pices start dancing around near the blade, in the air current inside the hood.

Dan

[Jim Dunn]

Jim,

Mine is mounted like your first pics. I allow it to freely float around so as to be able to cut narrow pieces. Haven't found it to be a problem, so far:)

One thing I did do was put star knobs in a couple of pivot points so as to be able to raise it and lock it in place for when I use the cross cut sled. I also don't see a counter weight on the end of the center rod. That makes the unit "float" and raise easily.

[Jim O'Dell]

Dan, nice set up. But I decided I wanted mint to ride up on the work instead of being pre positioned before cutting.

Jim, you're right...I haven't put a counter balance weight on it yet. Wanted to get everything else figured out first. I will do it though. Jim.

[Joel Earl]

...hehe....resurrecting the dead I am but I gotta. :D

Jim - I have the WoodCentral-ol' Badger Pond links but I cannot read what they measurements on all are. Is this up somewhere else where maybe it's clearer to a blind dude;)

This been a long time now - what would you change at this point if it was a do over? I see you too screwed the lexan - would you again or just fuse it?

In case ya all don't realize it ---- I got a project I'm about to start. Like today

[paul dyar]

I noticed you don't have counter weight. Is there a reason you don't have one.
paul

[Jim O'Dell]

Joel. Actually I have changed things some, and I have other changes planned. I have changed the ducting going to the overhead part so that it is against the ceiling a little more. 107586107587 Changes to make that I wish I had made originally. I should have made the nose of the shroud longer and slope up so that it will ride over taller items, like 2 X 4s, and my miter sled. That is the main change I need to make. Also, I wish I had used steel instead of the aluminum box tube. The aluminum flexes a little more than I would prefer, but it works fine.
Yes, I did add a counter balance to the arm. I was still working that idea out when I posted the pictures. Ended up putting a wood plug in the end of the tube, drilled for a 3/8" threaded rod. Added fender washers to the rod until I got the balance I wanted, and put an acorn nut on the end to hold it in place. 107588 I can add more weight, washers, if I change something on the business end. It's not too big, and was cheap to do. Two of my biggest requirements!! Figure if I ever want to make it more finished looking, I can get a big piece of shrink wrap and seal off the washers.:rolleyes: Thanks for the interest. Oh, and the down load I took from Wood Central showed lengths just fine. Want to borrow my glasses? :D I've had a computer crash since I did all of that, and I know the link is no longer in my bookmarks, but I'll see if I can find it and see if it prints out for me. Jim.

[Jim O'Dell]

Joel, I just went back and found the article. Are you clicking on the drawings? If not, that enlarges them so that you can read the sizes. It's still a little small, but legible. In fact, after you click on them, it opens up in a new tab, and then my cursor changes to a magnifying glass, and I can enlarge it again. Makes the parts larger than life size and still very clear to read. If that doesn't help, let me know and I'll write down the sizes for you. Jim.

[Sonny Edmonds]

I built one of those once.
Worked OK with my boosted suction.
2 weeks later it was laying in the back corner.
2 years later I threw it away while packing to move.

Now, if anything goes over my blade, it's the feeder. Which has dust pick-up built into it.
I don't need cumbersome devices in my way that are not working for me. ;)

[glenn bradley]

Jim, looks like you may have this resolved but just in case it might help; here's a shot or two of my low-dollar PSI unit, at least the parts that may help. The unit was really so-so with my 1HP DC. It really sucks up the stuff with my new DC and gets used more often. The wider material at the pivot points helps with side-to-side slop which is about 3/4". It could be less but I like the mechanism to move very freely and this is not a $300 device. It just pivots on the bolts so, loosey-goosey it is.

[Joel Earl]

Oh .... :(:(:(:(:(:(
I needed a double click and volia.//////

Thanks Jim - really truly appreciate the info and assistance. I may be further picking your brain so be prepared. ;)
And man - you were quick with the goodies!

[M. A. Espinoza]

Oh .... :(:(:(:(:(:(
I needed a double click and volia.//////

Thanks Jim - really truly appreciate the info and assistance. I may be further picking your brain so be prepared. ;)
And man - you were quick with the goodies!

Joel,

As fate would have it I am installing the same guard you are thinking of building. Built it from the same article I think.

I worked at a shop that had the Biesemeyer version and while not perfect I found it to work well enough that I decided to duplicate. Thought I would be thrifty and build my own.

I would recommend buying the PSI unit. False economy by the time you get all the stuff together and take into account your build time and working out a decent mounting option.

Part of what makes the Biesemeyer liveable is that is has enough adjustment built into it you can keep it out of the way. And if you want it completely out of the way it takes about five seconds. I had my home brew version mounted overhead in a way that didn't give adjustment and it was a much more frustrating setup.

I just finished doing a better mounting that is a rough approximation of the Biese. Seems like it will be OK.

If you weld, steel is the way to go if you are determined to do it on your own. It can be done with ply or wood but you really need to size the parts so it can resist that long lever it will be mounted to.

If I had to do it again I would buy the PSI. Could unpack, mount it and be working again in 1.5 to 2 hours I'm guessing. Maybe less.

[Joel Earl]

I was out picking up the aluminum and trying to find the right steel -- then the sticker shock hit. I need to look again at the thing and price the lexan too - called Rockler and a plastic shop. Both talking close to $60.
You're right in that this is becoming pretty spendy.

I think I'll do some more checking around - maybe buying it might become the better way at that. :(
Thanks

[Jim O'Dell]

I was lucky that the previous owner to the house we are in left several pieces of Lexan up to 20 X 20 in size. The top on my unit is the PTEG that my Clear Vue is made from. Ed at Clear Vue was kind enough to send me some scrap pieces to plaly with, so I was only out the pieces of steel and aluminum I used, plus the washers and all thread. Jim.

[Rod Sheridan]

I built one of those once.
Worked OK with my boosted suction.
2 weeks later it was laying in the back corner.
2 years later I threw it away while packing to move.

Now, if anything goes over my blade, it's the feeder. Which has dust pick-up built into it.
I don't need cumbersome devices in my way that are not working for me. ;)

Hi Sonny, what model of feeder do you have that has dust collection built in?

Regards, Rod.

[Joel Earl]

If I can find some scraps or leftovers from something I can see this staying reasonable but right now I'm sniffing the $120-130 range for all. That's nuts.

I think I'll make some calls and see if anyones got some things laying around tonight - Suppose I could go lighter/thinner on lexan and save some dollars but I see Lee/Sharkguard went to 3/8" for a reason.

The PSI does not appear to be to thick either - I called them and she was checking on it and will buzz me back. 3/16" kinda makes me nervous. Maybe it shouldn't???

Jim - what kind of time did you have to put into this in total??? - ballpark range ok as long as it isn't Yankee Stadium;)

[paul dyar]

This is mine, had the parts cut for over a year, just put then together. So for I like it, not as much dust on the floor.

Paul

[John Petsche]

great ideas!