Thread: Jet JPT 310HH combo terrific, but the dust/chip collection...???

Originally Posted by Larks

In jointing mode it's not too bad, there's a bit of fall through onto the lower table but not that much and certainly not enough to be at all annoying.

But when you flip the jointing table up and fold the collection port over for thicknesser mode (and follow the OEM instructions), I have found that most of the dust and chips dropped straight onto the floor...???

There is a loose flap of metal inside the dust hood which works via gravity (I think) which moves to work for the jointer or the thicknesser. Check that there isn't a wedge of timber jamming its function.

When I first got my JPT310HH the chip extraction was decent in both buzzer and thicknesser mode. But then I needed to rotate the knives for the first time I found that I needed to get the outfeed table a bees willy higher than what was possible. So I shimmed the outfeed table up by ~0.3mm which gave me enough movement to set it correctly. In doing this, I had to realign the tables to be coplanar and set appropriately to the cutter height etc etc.

In my adjusting of the tables, I have moved the tables away from the cutter to give more clearance between knives/table. Now when surface planing boards I get a lot of chips falling to the thicknesser table below.

None of the adjustments made to the buzzer tables affect the thicknesser mode at all. I found a few weeks ago that I was getting some compression marks in the boards after thicknessing which is caused by the shavings not being extracted properly. The knives in my machine need rotating again, but the compression marks do indicate that the dust extraction hood is lacking and choking the airflow. One day I'll build something with more mass for sound reduction and greater airflow.

My extraction system starting from machine is the, standard dust hood -> ~5m run of 100mm flexi -> ~3m run of 6" pvc -> 3hp dusty. I have all other ports in the system blocked when running the JPT310HH. My system is not ideal, especially the ~5m run of flexi...but I need that length to reach my router table.

Classic problems all round.

The stock 2HP DC is a "dog" at dust collection as it can only pull about 400 CFM through a 4" duct.
Go to the dust forum and read the sticky thread on how to modify the 2HP DC to get it to utilise 6" ducting.

While touching up the 2HP DC will help this will not completely solve the problem and the combo itself will need major modification.

Have a look at my thread on how to improve the dust collection on combo machines.

It's beyond me why in 2016 machines are still being made with 4" ports.
6" ports with a 4" adapter should be standard on all machines.

Originally Posted by Kuffy

There is a loose flap of metal inside the dust hood which works via gravity (I think) which moves to work for the jointer or the thicknesser. Check that there isn't a wedge of timber jamming its function.

That whole hood/flappy thing is designed all wrong. If you have enough flow I would remove that flappy thing completely.

I had the standard cutter block (without the helical head) and I never had any problems with dust collection. It was consistently excellent.

I had a Jet DC-1200 connected directly to the machine. There was no other ducting involved.

I suspect your DC is not performing as well as you think it might be.

Originally Posted by markharrison

I had the standard cutter block (without the helical head) and I never had any problems with dust collection. It was consistently excellent.

I had a Jet DC-1200 connected directly to the machine. There was no other ducting involved.

I suspect your DC is not performing as well as you think it might be.

You could be right Mark but I'm somewhat surprised that it's not working well enough to pick up on this function - the ducting is well sealed and direct flow to the DC and on all other equipment it seems to work well enough. Having said that though, I'm still using flex all the way to the DC while trying to decide where to lay a permanent PVC main line with a few PVC offshoots and short flex lines to my equipment.

I'm also taking note of BobL's thread that he linked above on improving the system.

I have a woodman jointer/thicknesser which has a similar gravity run flappy thing in the hood (at least I assume it's similar!). With similar symptoms, I found that when you apply enough airflow, the flappy thing gets sucked into the jointer position regardless of whether the hood is in the jointing or thicknessing position.

At the moment I just use some masking tape to hold down the flap when I'm thicknessing - that would at least confirm whether you are seeing the same thing or a different issue. I may remove the flappy thing as BobL suggests, will have to think about it!