Sliding Table Dust Extraction Nightmare

**LuckyDuck** · 25th January 2016, 10:30 PM

To the Moderators:

I have long struggled with posting photos in this forum. When I select and upload photos, they rarely load in the same orientation as they are on my computer. For example, one photo uploads upside down; another loads rotated 90 degrees to the right; another 90 degrees to the left. Maybe once in ten attempts, the photo actually uploads normally. I've tried again and again and again over the course of an hour. This has nothing to do with whether the photos are appropriately oriented in the first place. I have plenty of software, e.g. Photoshop, to correct photos. Rather, something goes wrong with the upload process. I have a Macbook Pro and wonder if this is the problem?

I have even tried saving photos upside down, and on their side, just to see if I can get them to upload the "right way up". NOOOOO! They still upload upside down, or on the other side! Ahhh. I was going to post this thread anyway, with photos all over the place -- until the upload window starting playing up further, and deleting some photos (just greyed out), and not allowing me to insert them into the post. I can't seem to take a trick on this one.

What can I do?

Here is the post without photos, until I can get advice on how to get photos uploaded properly. Sorry for voicing my frustrations. Always, appreciate your help! Lucky

I need your help. I'm writing this thread/post with a two-fold purpose. First, to work out what can be done, if anything, to improve the dust extraction problems I'm experiencing, and second, to formulate a "robust" letter to Herr Felder should we be unable to arrive at the kinds of improvements which are necessary for my safety, and for the safety of everyone else who happens to purchase this saw.

OK, you all know me as the dude who has a Delta Unisaw, which I have modified quite extensively, above and below the table, in accordance with the collective wisdom of this forum. Said Unisaw is now retired -- I could't bear to sell it as I've had it since I was fifteen! -- and I have purchased a Format-4, Kappa 400 x-motion sliding table saw. This saw is among the top-of-the-line saws made by Felder (Austria). In all but dust control, it is an amazing machine: 3.2m sliding table, 7.5HP motor, 400mm blade, with a separate, automatic scoring blade, CNC rip fence with full overhead touch-screen control, 3 x digital cross stops that are able to cut pieces from a few centimetres out to past 3m, with a resolution of 0.1mm, digital angle output for the outrigger, with a resolution of 0.1 degree, blah, blah, blah. It’s a nice machine.

Pictures A to F

The overhead guard is rubbish. Identical to the overhead guard on the Felder 700 series machines (65mm cross-section). I had one of those on my Unisaw. You guys said it was rubbish. While I hoped you were wrong, indeed I found you were right, and totally remade the overhead guard, with a 140mm port at the front of the blade. I’ll do similar for this machine.

Picture 1

No, my beef with Felder has to do with the below table dust extraction. Please note that I am not so interested in chip collection; I want dust extraction. Towards that end, I have a very powerful collector, the Felder RL250. Let’s assume, for the purposes of this thread, that I have plenty of airflow available. At least 160mm worth.

Here are the pictures… After an hour or so of cutting – hardwoods only – there is a massive spray of chips and dust around the machine.

Pictures 2-4

With the sliding table fully retracted, it reveals the space underneath the slider, where the operator can get access to the blades.

Picture 5

Here’s basically the same shot with the access door opened (blade down):

Picture 6

And blade up:

Picture 7

The below-table dust port is 120mm in diameter, and is situated at the very back of the main blade – could it be positioned any worse? – immediately below the riving knife.

Picture 8

Here is a picture of the area from a slightly different angle.

Picture 9

The actual port is nearly completely blocked by the cast iron shelf which is between the riving knife and the port “mouth”. This is probably the best picture I have of the port itself, as you can just see the flex:

Picture 10

With the access door closed, you can see how the below-table port is stuffed in a space too small for it, and the following sequence of pictures shows how it progresses from inside the cabinet base to outside. When the blade is adjusted to 45 degrees, the internal flex is partially squashed against the back of the machine housing. Utterly shocking!

Pictures 11-12

Get this! There is NO floor to this machine. It is completely open. After an hour of cutting timber, the floor underneath the machine looks like this:

Picture 13

I think this picture shows how narrow the gap is below the blade:

Picture 14

There is so much dust around the arbor that despite the dust extraction, a cloud of dust erupts into the air every time I turn on the machine, and especially when I use the scoring blade. Are you feeling my outrage?

Picture 15

Modifications will be difficult as there is cast-iron everywhere. For example, the housing directly below the blade, on which the access panel door is hinged, is cast. So is the actual port on which the flex attaches. Predictably European in construction, but breath-takingly badly designed. I’ve thought about trying to relocate some new flex directly below the front of the main blade, i.e. between the main blade and the scoring blade, but I fear there is not enough space. If I abandoned the use of the blade on an angle, i.e. laying it over to 45 degrees, I could cut into the access panel itself and install a port more-or-less directly below and alongside the front of the main blade. But if I tried to lay the blade over, the new port and flex would jam against the sliding table.

I can’t think of anything else to do except complain long and loud to Felder. The Queensland Rep is sympathetic and has encouraged me to write a letter to Johann Felder in Austria. Evidently Felder listens more to paying customers than their reps…

In any case, I’ve got to do something. The saw is magnificent. The slider spectacular; the digital goodies seriously efficient and fun to boot. The machine is everything I expected it to be except for dust extraction. I expected that to be poor but not this poor. How could it possibly pass the Euro standards for dust control. Forget about the Coke cap full of dust that BobL says puts our air quality into dangerous territory…you can see from the pictures that we’re talking a much more serious problem than that!

Apologies for the length of this post. All thoughts, advice, rantings, whatever, gratefully received. Cheers.

**elanjacobs** · 25th January 2016, 11:08 PM

Only 6 pics loaded, so can't see what you're talking about, but welcome to the "panel saws have bad extraction" club.
We have an Altendorf WA80 at work (one day the boss will snap and buy me an F45

), also open base, 6" hose on the blade housing, 3" on the guard (should be 4"), hooked up to a 15kw extraction system and the floor still gets messy.

**Kuffy** · 25th January 2016, 11:23 PM

Yeah, bloody panel saws are a nightmare for dust extraction. All of them that I have worked with spew dust out in every which way. As far as the machine not having a floor, i put a sheet of cardboard under my chinese panel saw. Once the dust has built up a nice even 2" thick layer, I pull the cardboard out and funnel the dust into the bin. I have often thought about making a downdraft table type thing to sit under the machine. But without knowing how effective it would be, i havent been inclined to do it.

**LuckyDuck** · 27th January 2016, 02:01 PM

Originally Posted by Kuffy

Yeah, bloody panel saws are a nightmare for dust extraction. All of them that I have worked with spew dust out in every which way. As far as the machine not having a floor, i put a sheet of cardboard under my chinese panel saw. Once the dust has built up a nice even 2" thick layer, I pull the cardboard out and funnel the dust into the bin. I have often thought about making a downdraft table type thing to sit under the machine. But without knowing how effective it would be, i havent been inclined to do it.

Thanks guys, not looking good for my slider. I'm in lengthy discussions on the Felder Owner Group Yahoo forum, and a couple of the guys have the same saw. We're going to write a letter to Mr. Felder about the issues and see if it gets us anywhere. Wish us luck!

I'm not so worried about the dust that falls to the floor although it is a bit disconcerting. I'm more worried about the plume of visible and invisible dust that literally takes my breath away when running the machine. Will report here if I get anywhere. Thanks.

**LuckyDuck** · 27th January 2016, 02:10 PM

02 vent between main and scoring blades.jpg 03 better picture of the 120mm port.jpg 01 gap between blade and slider.jpg 07 space under the blade, looking straight down.jpg 05 close up of the cast shelf in the way.jpg 04 sheet metal above and thick steel below.jpg 010 general picture from another angle.jpg 09 think steel behind main and scoring blades.jpg 08 blade removed, fair bit of venting space behind the blade.jpg

For what it is worth, here are more pictures, although I am unable, no matter what I try, to get them the right way up. My apologies as it must be frustrating for you as well as me!

**LuckyDuck** · 27th January 2016, 05:59 PM

Could anyone please help me with the technical questions about the saw's specifications. In the manual that came with the saw, it says that the 120mm port (under table) must have a minimum air speed of 20m/s, a minimum pressure of 1824Pa, and a minimum volume of 814m3/hr (at 20m/sec). For the 80mm port (useless overhead guard), the manual says I've got to have a minimum air speed of 20m/s, a minimum pressure of 953Pa, and a minimum volume of 362m3/hr (at 20m/sec). These numbers don't add up do they? For starters, I didn't think it was possible to get 20m/sec of airflow through an 80mm pipe! I know this is in metric instead of CFM and FPM, but I would be very grateful for any help. Thank you!

**LuckyDuck** · 27th January 2016, 06:01 PM

Elanjacobs, thanks for your sympathy. I'm screwed if you still don't have any good extraction despite much larger ports. Is it the case that "all" sliding table saws have rubbish extraction, or just that yours and mine is rubbish? For example, is the F45 significantly better? I wish I could have a good look at a top of the line Martin and see what they do below the table! Cheers.

**elanjacobs** · 27th January 2016, 06:46 PM

After having a look at the pics, a couple of thing's come to mind.
1) Your zero clearance insert is going to cause you grief. It stops pretty much all downwards airflow around the blade, so the first thing I'd do it get rid of it. With the scoring saw for laminates and a good blade for solid timber you shouldn't even need it.
2) The blade housing seems to have been poorly designed for dust extraction. It's cramped and has bits sticking out all over the place; the two that caught my eye are the bit under the riving knife and the bit in front of the scoring saw.

I'll try and remember to get some pics of what ours looks like, but with the blade removed I can get my entire arm in there quite comfortably. To be fair, it does take a few weeks for the pile to build up and for general work the extraction is very good, but once you tilt the blade the floor gets messy very fast. There's certainly no puff of dust when we turn it on, even with 400mm blade.

I had the pleasure of using F45s at trade school 5 years ago and they had enclosed cabinets, can't really comment on the mess as the floors were swept daily.

I think the main thing with panel saws is that they're generally aimed at commercial users who a) have people at the bottom of the food chain to clean up, b) expect there to be a certain amount of mess on the floor pretty much all the time and c) often have extractors big enough to compensate a bit for the sub-optimal design.

**Lappa** · 27th January 2016, 07:21 PM

I have problems also when uploading from my iPhone or iPad so I upload my pics. to iCloud on my PC then to a forum pic. folder and rotate the pictures. Most of my time on the forum is on my iPad but any time I need to upload photos, I use my PC, not my iPad.

**Jeff Leslie** · 27th January 2016, 10:00 PM

I'm sorry but I can't agree with all that has been said beforehand.

Assuming you are running a decent cyclone, ports both above and below the blade, extraction of the bad stuff should not be a major problem. Forget any talk about zero clearance on panel saws as the extra gaps only help with the extraction from below. Solid chips on the floor are inevitable.

The main problems occur when you use the scribing blade as it sits too forward for the o/head chute to work properly. You are lucky to have such a large blade such that you are not compelled to dispense with the o/head guard.

**elanjacobs** · 27th January 2016, 10:06 PM

Originally Posted by Jeff Leslie

Assuming you are running a decent cyclone, ports both above and below the blade, extraction of the bad stuff should not be a major problem.

15kw can't keep ours clean, is that not decent enough?

Forget any talk about zero clearance on panel saws as the extra gaps only help with the extraction from below. Solid chips on the floor are inevitable.

Most extraction IS from below

The main problems occur when you use the scribing blade as it sits too forward for the o/head chute to work properly.

The scribing blade is entirely under the table, the overhead guard does absolutely nothing to help

You may disagree as much as you like, but I can tell you from experience that this is how it is.

**LuckyDuck** · 27th January 2016, 10:10 PM

Thanks for the tips Lappa. I've give them another go and hopefully get my pictures sorted next time!

**LuckyDuck** · 27th January 2016, 10:16 PM

Thanks for your comments, really appreciate having feedback from another slider user! I would love pictures of yours but no hurry. My saw is not going anywhere any time soon -- unless Felder gives me a refund! LOL I don't have a 15kW extractor but mine is big enough at 7.35kW. I know there is enough air because I used to have outstanding results on my previous saw after it underwent surgery as advised by members of this forum. But the slider is a different animal. I agree that the riving knife assembly is in the way. Spot on. I really want the port directly under the front of the main blade. I also get your point about the ZCI, which is an aftermarket job, but I need it to keep all the slivers (solid wood) from binding on the blade. I think if the blade is properly vented below the table, the ZCI should not be a factor -- hmm, but currently there is no "proper venting" that's for sure! The guys over on the Yahoo FOG thought I was going to go to the saw with my angle grinder -- not yet! But I'm tempted! Cheers

**elanjacobs** · 27th January 2016, 10:30 PM

Don't know what size timber you normally work with, but I have very few problems with slivers binding on the blade

**Jeff Leslie** · 27th January 2016, 11:23 PM

I am not about to get into any arguments on this. My 15+ years of using a Minimax CU300 combo machine tells me that most uncaptured visible chips come from the top of the blade. Poor o/h collection ports too far from the scribing blade or ports that have to be disconnected for say ripping hardwood. While my personal tests with my $1K + dust mask is far from scientific, I am more worried about dust coming off my dual drum sander and my lathe tools.

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