788 final product vac system

[Carl E Jacobs]

modified a little more ,illiminated itermittent whistle ,installed vac. lift enlarged upper vac.pickup tube ,no longer gets in the way of blade change or rethreading blade in project ,t-ed source ,Happy now no-saw-dust ! Gets it all!

My best !
Carl

[Tenfingers 2]

Carl,

Could you explain / photo how it gets the under table dust?

[Carl E Jacobs]

I made the table a hollow manifold! Vacuum only pulls around the blade top and botton and the pattern on top via the visible hole drilled in the table top.

I lived in Burton ,Ohio for years. I may polish up the appearance later, now that I know what works ,and it works real well . Look at the other posts you can see ,the manifold arrangement on the proto-type .I think there are two shots of under the table. Every other
attempt I tried ,or saw of others ,were bulky in the way and looked like a octopus,helped but did not really cure the problem. The tray arrangement has nothing to do with the vac.system ,I added that to cure problems associated with the slanted table ,to catch the cutouts ,I have found it very handy for other things as well!

If you have any other questions ,or suggestions let me know!

My Best!
Carl

[Block]

I started building a small stand which will hold PVC pipe. The pipe will be verticle then angle (likely at 45 degrees) under the saw's table to suck in falling sawdust.

They should simply have a hole in that black metal area under the lower arm where the sawdust falls onto (I have the Delta 40-690). In other words, just behind the tilt lock-down knob.

One thing is tricky - since the table tilts so far both ways, it's hard to route a 1 1/4" inner diameter hose w/o limiting the table's max tilt angle. My design might limit the table's travel, but if really needed I could simply move the vacuum stand to the other side of the saw. Or, if I use flexible sump pump pipe and add some bends/turns, maybe it can be routed w/o getting in the way of the table. I connected an old canister vac to 10' of flexible sump pump pipe and it whistled like crazy! Maybe a much shorter length will be OK.

I've only had the saw a few weeks and the most important project so far was my daughter's pinewood derby car. She/we came in 1st in her age group (Juniors) and 3rd overall out of 177 girls! They had two races, around 90 in each race.

[Carl E Jacobs]

trial and error!

Thats the only way your going to be comfortable ,try it ,see how it works ,try the saw ,does it change anything ,any whistles ,is sound bearable ,how much does it help,what about the top,all the questions ,Does it effect blade changing and so on,Keep Me Posted ,You could find a better way!I will respond to your posts,
Good Luck ,
MVB
Carl

[Block]

I got it together temporarily (don't have pipe clamps/holder so I used duct tape to hold the pipe to the stand). I did not end up using the sump pump pipe (not really needed plus the noise might still be there even in a 1-2' length). The 1.25" PVC pipe got the suction close enough to the blade to get all of it (and it's not a super powerful vac). I bought a short 2' section of pipe (drove my car to the store instead of the van - oops) but it was long enough. I used 13" vertically against the stand, then a 45 degree coupler, and the remaining 11" angles over to the saw's blade.
On the left side as you face the saw, the blade guard somewhat gets in the way (not sure if all if the 788's came with one). The pipe ends at the blade guard and is mostly a tad higher than the blade guard.

The table tilts about 30 degree before it hits the blade guard. If needed I can simply move the stand to the other side of the saw or not use it during that cut. A narrower PVC pipe (perhaps two of them) would allow the table to tilt all the way but this is good enough for me. If you run a narrower pipe parallel to the lower arm, the table won't hit it, and a narrow pipe could be run closer to the blade. I almost did it that way but probaby would have ended attaching the pipe to the saw and I don't want to do that.

Another shortcoming is that the lower arm (the blade clamp) could hit the pipe if the stand gets knocked/slid over. If that happens even just once I'm going to replace the top section of PVC with cardboard tube (from Estes rockets - I have extra tubes).

Since the thumbscrew for changing blades is on the right side, changing blades should not be a problem.

What I like about this method is that I did not need to modify the saw. If I were braver, I'd cut a hole (or multiple 1/4" holes) in that cupped/curved metal under the blade where the sawdust tend to fall, and epoxy a hose there under the saw/stand. I think there's nothing in the way under that part of the saw, and perhaps the saw should come from the factory with a vac connection there.

[Block]

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[Hawaiilad]

Block I really like your set up for the shop vac. Are you using anything for the dust on the top? I wonder if your system would work snaking it up and over the top using clear hose with a small 45 bend to the table top?

[DWSudekum]

That system looks good however I think I see an issue. What happens when you tilt the table?

DW

[Carl E Jacobs]

Looking Good!

I'm a visual person,My mind converts my ideas to pictures,reading something without pic's confuses me.Some time, I'd like you to tell me how you got your pix without thumb nails .The table looks like cast alum. ,is it? Your on the right track,keeping fittings to a min.and smooth ,smoothing "rounding all leading edges" of the entrance hole will quiet sound .I never glue fitting s then I can change and rechange MY design as new ideas immerge pipe is cheap fittings are not.The smaller pipe you go to ,you lose power, and gain sound.
Good ,gage ,What ever size vac. you are using ,measure ID of hose ,idealy,
thats what you have to work with,go larger you loose volume &power,BUT less suction noise,smaller you loose power&volume .BUT more suction noise.
Distance,nonsweeping fittings all restrict flow,Just things to keep in mind as you design your system .The closer you can stay to the hose ID the better it will work and the quieter it will be ! All designs are based as much on the limitation as the are on the improvements ,your after a compromize that you can live with and still does the job.I made a mistake in drilling my tableand the 1/16" groves I put in my table ,They don't create a problem ,but with the upper adjustable arm vac the were not needed ,I tried to do it all from the bottom and was not able to.Like I said it was all trial and error! Let me Know how your doing as this is a WIP ,Any thing I can help you with just let me know!
My very Best!
Carl
P.S. For me at least the journey is as rewarding as the results!

[Carl E Jacobs]

Clamp tip

I make wooden adjustable pipe clamps for proto type stuff ,Cut the shape of a sq block 1 1/2" wider than your pipe sq. Drill a hole center a snudge larger than your pipe ,drill a hole for a screw to lock you pipe in the position you want it,center top to center pipe.drill 1 hole ea side of pipe hole to mount screws 3/4 " longer than block ,you get the idea now you can adjust& twist to position pipe any where you want and it will stay there ,Dull locking screw tip
so you don't damage or go thru.pipe ,I always shape block like a bell to reducemounting screw length ,looks better to.Just a thought instead of tape.
M.V.B.
Carl

[Block]

Good idea - I want to be able to move the pipe and was tempted to use Velcro, but I did not have any straps long enough, and the pipe might slip. The lip of the 45 degree connector is above the wood/stand, but that's all that keeps the pipe from sliding (other than the tape (or Velcro)).
Maybe instead of a "setscrew" I could use thumbscrews, one on each side of the pipe, to press the wood block against the pipe to hold it. The block of wood would need to be sized such that it does not reach my stand of course, so the force goes onto the pipe.

[Block]

Thanks. Yea, I thought about rigging up something on the right side since that's wherre the dust blower blows the dust, but it would be quite a bit of extra work and that dust doesn't bother me as much (doesn't get all over the saw and stand into every nook and cranny, plus there is a lot less dust on top of the table). And knowing, me I'd spend so much time designing it that I'd never get started. :-)

The PVC pipe is 1.25". Its inner diameter is slightly larger than the outter diameter of my old canister vac. the end of the vac's hose has a bend, so if I ram it intot he PVC, it gets stuck, but I use tape anyhow to seal it. The pipe was 2' long ($2-$3 at Home Depot - was in a hurry and didn't have our van, otherwise I would have bought 8 feet for something like $2 more).

The table is cast iron, but painted grey (from factory) except for the top.

To tilt the table left, I would move the stand/pipe to the right side. That's partly why I made it moveable, not attached to the table or saw in any way.

Block I really like your set up for the shop vac. Are you using anything for the dust on the top? I wonder if your system would work snaking it up and over the top using clear hose with a small 45 bend to the table top?

[Block]

The canister vac (not a wet/dry vac) has decent motor - it's not super high RPM and loud like many new vacs are. It's very old and thus does not have a HEPA, so I wonder if I'm doing more harm than good healthwise - might be blowing very fine dust into the air.
I put a 20" box fan with a "fine particle" (but very restrictive) furnace filter nearby (when I remember to). The vac has a paper bag which looks solid to the eye, so the dust would need to be pretty darn small to get through.

Amazon has a canister vac (Electrolux or one of their other brands) with HEPA for $220 that is touted/reviewed as being very quiet. I doubt I'll use my saw a lot, so I suppose I'll hold off for now.

If I want to make my current vac quieter, could I use a light dimmer (or similar) to cut the voltage just a bit? It has more than enough suction - sawdust is easy to pickup and it is just 2" from the end of the PVC pipe. It seems to be catching 100% of the falling dust currently. Also, lowering the voltage would slow the motor, and hopefully less dust would be pushed/forced through the filter into the air. The vac is fairly quiet, but if I was sawing for hours it would be annoying, and it's loud enough that I probably can't hear the radio well (I haven't used it much - just built the thing yesterday!).

[Block]

BTW, I used the saw to cut my daughter's pinewood derby car. We (mostly me unfortunately) spent many hours working on it right up to race time. Last year was her first year. I used my friend's Ryobi, which was "difficult to use" let's say (to be kind). She came in 2nd in her age group and 6th overall out of 105 girls.

This year we did a few more speed tricks and she came in first in her age group out of 177 girls and 3rd overall! 2nd place was only 0.0001s (not a misprint!) ahead, and 1st was 0.002s ahead. Our car looks liks a grand prix car - probably would have at least come in 2nd if we had a boring "flat plate" design. They say aerodynamics do not matter at these speeds, which is basically true, but when you're only 0.0001s behind it probably matters.