Thread: Dust Deputy fails

Jill

From what you have said, I think the clue is that your plastic bucket is imploding. This sounds to me as though there is insufficient airflow. This may be a blockage from sawdust or more likely a larger object or a component of the ODD has failed. I understand the principle of the cyclone effect but am not familiar with the ODD.

I do know that if you clamp the palm of your hand over the end of your vacuum hose it with the vcuum switched on it will collapse the plastic bucket, garbage can etc. The vacuum cleaner attempts to pull a perfect vacuum (which it doesn't have a hope in hell of achieving) and in the process overheats.

I would look at the opening on your router and see if that is not too small. Some vacuum hoses have a small sliding vent near the handpiece. If yours has this, try opening it to increase airflow.

My other suggestion would be to connect the router directly to the vacuum and see what happens. It is just a process of eliminating a possible cause. Bear in mind that if the initial problem caused severe overheating the vacuum may have damaged and now it could overheat with almost no provocation even though the original problem has been removed.

Do you have another vacuum to try? Are you willing to try?

Regards
Paul

Hi Jill,

I cannot say whether the Dust Deputy has suffered internally in the exercise, but the restriction in the dust collector at the router will be the cause of the problem.

The DD relies on a high speed airflow to circulate the router dust around the cone assembly. With sufficient speed, the particles have enough acceleration to seperate from the airflow, and can then drop into the bucket. The fact that all the dust went straight to the bag asembly suggests that there was insufficient speed through the DD to allow seperation.

Secondly, all vacuum cleaners rely on the exhaust airflow (after filtering) to cool the motor. If they cannot establish sufficient airflow, the motor speed drops and the motor works harder to develop the airflow. The motor noise also becomes louder. With the reduced airflow and increased power consumption, the motor will tend to overheat as yours did. Obvious with a household vac and crevice tool being partly obstructed, except that in the case of the household vac the obstruction is temporary, whereas with the router it is permanent.

The dust collector at the router beeds to have a fairly large and unobstructed inlet area to maintain the airflow for the rest of the system to work properly.

Jill, are you sure you connected the hoses the correct way on the ODD. If the dust etc is getting through to the vac, it sounds suspiciously like no cyclone effect, which reversed hoses would explain. Vacuum must connect to the top of the ODD.

Many thanks to Bushmiller and malb for your well thought out and logical approach.

I agree with you about the restriction on the router dust fitting being the cause of the problem- looking down it, the cross sectional area where the dust comes into it near the bit is about 1/3 the area of the 32mmOD outlet tube.

I tried another vacuum cleaner connected to the ODD, and it too collapsed the plastic bucket.

In the end, to finish the first mortice, I ended up connecting the outlet directly to the domestic vac cleaner, so that filter will be well and truly clogged - will have to clean it out before proceeding with the other mortices.

I do have a Triton dust bucket , but that too has the same problem of the filter in the lid quickly clogging up

I thought of getting a stronger bucket ( metal), but I expect that would collapse too with the atmospheric pressure

so, looks like I am stuck with a direct connection to a vacuum cleaner, with frequent emptying and cleaning of the filter

Vacuum must connect to the top of the ODD

I have been caught with that one previously, Chris, on a Fien dust separator I made and did not work. See here You will see the wrong hose connection in the test run photo

Many thanks for the suggestion, but I have it arranged such that the vacuum cleaner hose can only fit the top of the ODD

It appears clear from what you have described that the seal on the bucket was not airtight- hence no cyclone action and dust gets sucked up into the vac.

I have had a bucket implode on me as well but managed to maintain an airtight seal.

A stronger bucket will do the trick - it doesn't create a complete vacuum in the bucket, just a partial one so it should be strong enough

thanks for your comment, TP1, but it certainly is a very air tight lid, as you would expect on a paint bucket. I have difficulty opening it.

I took the vacuum hose off the router and put my palm over it, and the bucket crumbled again immediately.

The dust normally falls in to the plastic bin when I have the ODD connected to the Kapex SCMS - much better air flow then, and nothing goes in to the vacuum cleaner

Originally Posted by JillB

thanks for your comment, TP1, but it certainly is a very air tight lid, as you would expect on a paint bucket. I have difficulty opening it.

I took the vacuum hose off the router and put my palm over it, and the bucket crumbled again immediately.

The dust normally falls in to the plastic bin when I have the ODD connected to the Kapex SCMS - much better air flow then, and nothing goes in to the vacuum cleaner

That is intriguing! Is it possible to reduce the suction power when the DD is connected to the router? I'm just guessing here, but something is causing the cyclonic action to fail. The smaller diameter of the router outlet can cause the air velocity to increase. Since you have established that there is a strong vacuum in the DD, perhaps the higher air velocity is having an effect on the DD performance.

Originally Posted by TP1

I'm just guessing here, but something is causing the cyclonic action to fail. The smaller diameter of the router outlet can cause the air velocity to increase.

But the airflow volume to decrease.

Originally Posted by TP1

Since you have established that there is a strong vacuum in the DD, perhaps the higher air velocity is having an effect on the DD performance.

When the reduced volume of air enters the larger pipework it's velocity will decrease and reduce the performance of the DD.

If possible provide a method to increase air flow into the pipework just after the router, to allow the DD to do it's job.

Had a closer look at it today. the restriction on air flow is actually two fold:

1) The inbuilt restriction of the dust outlet on the router fitting where it reduces to about 1/3 of the outlet tube size

and

2) The 24mmOD template guide, which is largely a big plate which covers the normal opening around the router bit, except for a 24mmOD x 6mmL cylinder surrounding the 1/4" router bit - leaves very little space for any air flow.

No wonder the poor little vacuum cleaner was struggling

Jill

Good to hear you have resolved the problem. The last word will be when you return to the SCMS and everything works as before.

Regards
Paul

Thanks Paul. I think that I have only found the root cause as to why the ODD does not work in this situation.

using a vacuum cleaner without a dust separator is not really a good solution for a router, as the fine dust will quickly clog the filter

not sure how best to proceed.

I think Breez
y has the answer...
If possible provide a method to increase air flow into the pipework just after the router, to allow the DD to do it's job.

You have rightly identified the issue, large bit and guide bush restricting air flow. Also chips from the bit will block the router dust outlet much more than fine dust.

Can you fit a Y connector between the router and the cyclone? Let the router use one branch and control extra air flow into the other branch (as an experiment try using duct tapee to seal off some of the opening to get the amout of air right) with the centre connector of the Y going to the dust collector.

Good luck with it.

Chipman


I had similar problems with a shop vac trying to pic up wood chips off the floor...totally useless. It is possible to buy a bulk pick up kit for them which is basically a bigger diameter hose.

Many thanks for this , Chipman, I shall start looking for a 32mm OD Tee connector