Finally a wide belt sander and dust extraction upgrade, ideas please?

[Albert Lee]

hi all

I have finally bought a mint condition second hand 37" SCM wide belt sander ($1350USD!) and will be getting some serious ducting (lip-lock system) installed.

some background:
The sander is a 940mm (37") wide SCM Uno, there is no air nozzle blower to clean the belt and there is only one extraction hood at the top, it measures 125mm x 85mm, the cross sectional area is equivalent of 125mm dia ducting.

I plan to add air nozzle to clean the belt as I don't want the sand paper/belt to heatup and supposedly it will clean the belt better. the SCM standard blower uses 700 litres/min (no timer) and the sander uses 100l/min for belt tensinoning, the compressor I plan to get is capable of 39cfm ( old but serviced Hydrovane, the owner wanted $900, worth the risk?)

The ducting will be the smooth lip-lock system, the extractor is a 4kw - 24 socks air filter system (this will be upgraded to an outdoor extraction unit in the near future.)

Plan A:
I wanted to add extra hoods, the main trunk is 250mm diameter, this is about
2 x 150mm
1 x 125mm (this will service the factory hood)
The location of these are;
1 x150mm immediately behind the factory hood, and 1x150mm at the back of the sander near the conveyor belt.


Plan B
3 x 100mm
1 x 150mm
1 x 125mm ( or just use 1 x 150mm)

I plan to add the hoods in the following positions.
150mm hood same as plan A, the 3x 100mm will be along the back panel close to the conveyor belt, all 3x100mm will be joined up and merge into a 150mm.

which is better? 3 openings of 100mm or 1 x 150mm at the centre?

the hood at the rear of the sander will be pointing 45deg up in both case.

The shaving/dust will need to travel 16 feet before it reaches the fan( 3 feet up, 8 feet across, 3 feet down)

photo.jpg

The ducting:
Due to possible future expansion, I will be using Dantherm ducting, very smooth and lip-locked, the system will serve 2 machines for now, one is my Robland combination and the other will be the SCM sander.

The extractor is a Holytek 4kw 3200cfm 24 socks extractor ( similar to Dantherm s500) the main trunk will be 10", from the extractor inlet it will:
1. Go up 3 feet,
2. 90 degrees bend(1.5x radius)
3. 6'8" across the workshop.
4. Diverter valve
4a1. 90 deg bend down (1.5 x radius)
4a2. 10" to 3x6" branch
4a3. Connect all the 6" to the sander hoods

4b1. 10" trunk carry on for another 6'8" (or add a reducer from 10" to 6")
4b2. 90 deg bend (1.5 x radius)
4b3. Y branch from 10" to 4 x 5" ( or from 6" to 3 x 4")
4b4. Connect all the 5" to the combo hoods

here is a picture to help:

SKMBT_C28014033110181.jpg



Comments and thoughts please?

[Jim Andrew]

Sounds like the police will be searching you out for the sander. As to all the measurements in mm, I have no clue. The feet and inches make sense, but sorry not the mm's. Your dust collector sounds huge, should work for your sander,don't know about cutting it down to 6", probably could handle 2 6" lines. Don't understand the 24 socks term. You don't mean the dust collector has 24 bags do you?

[David Kumm]

I would try it stock at first and see where you need the help. Velocity at the port is a big deal because the sanding is so far away. The edges will be the worst but I'd use it a little and modify. Every time i get ahead of myself and mod before use, I find my theory isn't quite the same as practice. And I modify everything. Dave

[Kevin Jenness]

I would second David's suggestion to try it as is. Scmi machines are usually well designed with regard to dust collection. Any additional ducting would best be located as close to the contact roller as possible, and at the infeed side as that is the direction the dust is coming off the work.

For comparision, our Sandingmaster single head machine works reasonably well with its stock hood terminating in an approximately 150 mm duct, and it would be difficult at best to fit another tapered duct in behind the existing one close enough to to the work be effective.

[Albert Lee]

Sounds like the police will be searching you out for the sander. As to all the measurements in mm, I have no clue. The feet and inches make sense, but sorry not the mm's. Your dust collector sounds huge, should work for your sander,don't know about cutting it down to 6", probably could handle 2 6" lines. Don't understand the 24 socks term. You don't mean the dust collector has 24 bags do you?

here is the pic of the extractor and the sander.

photo.jpg

[Kevin Jenness]

Albert, just one more thought. If you find the dust extraction with the stock hood is inadequate, you might find that hooking it up to a larger branch size, say 7", would increase the air velocity at the collection point, though it might also result in dust settling out in the branch as the restricted airflow slowed down.

While researching the purchase of our current widebelt I visited two shops with an SCMI unit that looked much like yours, and neither shop owner complained about the dust collection on their machines (both run clean shops so I think they would have commented if it were an issue).

[Rick Fisher]

I have the little brother 25" version of your sander and can report that the 125mm dust port is more than adequate for me.
About once a year I clean out the ledges on the inside of my sander with a shop vac. I don't really think modifying it would change that ..

Mine is serviced from a 6" pipe and a Felder RL-160. The reducer sits right on top of the sander. Even the blast gate is 6" ...
I think in my case the 6" pipe is the answer unless the dust collector is sitting right beside the machine ..

I would use as is.. BTW .. $1350 is an amazing deal for a functioning SCM sander. I think I paid $5000 for my 25" ( 7 years old at the time ) ..

Oh..

I don't have pneumatic belt cleaning either.. I have never felt I needed it .. I was going to say, I ran my SCM 25" sander off a Makita 2400 twin tank compressor for about 3 years. It ran the compressor hard but never hurt it .. I changed the oil a few times .. Since then I loaned the Makita to a buddy.. Kinda wish I had it back again..

The big shop compressor is great.. I have an 80 gallon Champion. The downside is waiting time and noise.

[Jeff Duncan]

A couple thoughts,

1st) I agree to use it as it was designed first to see if there's any reason why you should tamper with the design. You'll probably find there isn't, but at least that way you'll know.

2nd) You should not need an air nozzle to cool the belts. If you learn how to sand properly they shouldn't be getting overly hot anyway. The reason belts might fail due to heat is that they've been used improperly….abused. Learn how much you can safely remove at each grit and stay within those guidelines and you'll be fine.

FWIW I run a 43" wide belt sander with a 7" connection to a system that in theory can pull in the 3500 cfm neighborhood…(7-1/2 hp Torit cyclone). The 7" connection seems small to me, but it collects the dust as it should and as such there's no reason to modify it.

good luck,
JeffD

[Brian W Smith]

One of the things we do here at our shop is build custom dust management systems.........and no,I'm most definitely NOT soliciting.But will say,you're going to have to play with a few different setups,because of what's downstream......but that ain't the reason for the post.

If you want to really get a handle on wide-belts......spend the money and get a copy of Howard Grivna's book.Hope linking this is PC with the moderators?

http://www.sandingsystemsinc.com/

[Albert Lee]

I have the little brother 25" version of your sander and can report that the 125mm dust port is more than adequate for me.
About once a year I clean out the ledges on the inside of my sander with a shop vac. I don't really think modifying it would change that ..

Mine is serviced from a 6" pipe and a Felder RL-160. The reducer sits right on top of the sander. Even the blast gate is 6" ...
I think in my case the 6" pipe is the answer unless the dust collector is sitting right beside the machine ..

I would use as is.. BTW .. $1350 is an amazing deal for a functioning SCM sander. I think I paid $5000 for my 25" ( 7 years old at the time ) ..

Oh..

I don't have pneumatic belt cleaning either.. I have never felt I needed it .. I was going to say, I ran my SCM 25" sander off a Makita 2400 twin tank compressor for about 3 years. It ran the compressor hard but never hurt it .. I changed the oil a few times .. Since then I loaned the Makita to a buddy.. Kinda wish I had it back again..

The big shop compressor is great.. I have an 80 gallon Champion. The downside is waiting time and noise.

Hi Rick, I have read some of your feedbacks on the Felder RL and Wide belt sander when I was searching for the discussion on WBS, you are like a fore runner and I learnt alot from your discussion with others

The sander has the pad that you can move up and down to smooth out the sanding lines, its not just a roller/sander. but the sandbelt length is about 1500mm only...

I am undecisive on my ducting, the extractor is a 4kw unit with 20 inch impeller, the advertised CFM is 3200, max speed of air is 6800FPM, the inlet is 10inch, the actual path from the sander to the extractor is 14-16 feet.

I have been told to use 8 inch duct. but I feel this may suffocate the extractor and making it not able to move enough air?? on calculation if I use 8 inch duct, assuming 4000fpm to move the fine dust, the extractor needs to be no smaller than 1331CFM. if I take 60% of the advertised value of 3200, this is about 1920CFM. not sure if I am doing the calculation right here.

I have bought the hydrovane compressor yesterday, its 25-30 years old but I have been told these hydrovane compressor they wear in rather than wear out, on the noise level its on par with the mid priced rotary screw compressor, I really cant have much noise as I am in a residential neighbourhood. the council here is pretty tight on noise level and they have the right to confiscate your equipment and give you a fine if its excessive, therefore I have ruled out the piston compressor from the start.

[Albert Lee]

One of the things we do here at our shop is build custom dust management systems.........and no,I'm most definitely NOT soliciting.But will say,you're going to have to play with a few different setups,because of what's downstream......but that ain't the reason for the post.

If you want to really get a handle on wide-belts......spend the money and get a copy of Howard Grivna's book.Hope linking this is PC with the moderators?

http://www.sandingsystemsinc.com/

thanks for that. yes I kinda felt that I may have to play around with it to see what is the best/optimal way to run it....

will have a look at the site. cheers.

[Kevin Jenness]

Plenty of helpful info here: http://www.airhand.com/designing.aspxhttp://www.airhand.com/designing.aspx

[Rick Fisher]

Albert.

One thing I have found is that my little wide belt is brutal on the filter in my DC .. I actually made a pneumatic filter cleaning apparatus out of pure frustration .. The Chips from a planer or Jointer or the dust from a table saw is really no problem but the Wide belt and to a lesser degree I think the edge sander creates such a huge volume of powdery dust, it cloggs my filter and actually restricts airflow.

Not sure if that will affect you but its something to have in the back of your head while planning your system.

[Randy Gazda]

Albert, before you worry about collecting all the dust from the sander, I would make sure the collector bags are stopping the small dust. If they are the "filter bags of old" they are passing the dangerous dust back into the air. Plenty of threads on this site about filter upgrades.

Just my two cents worth.

[Albert Lee]

thanks Rick, I know the sander will create a lot of fine dust that will clog the filter fast, I have a habit of cleaning the filters in my workshop regularly, I like machine working efficiently, if they are not cleaned regularly I feel the pain...