[LeeWay]

Guys I looked through the forums and found nothing on drum sanders. They aren't normally cnc. I won't actually cnc this one either, but it needs some better accuracy.
I bought one of these and it arrived about a week ago.
Grizzly.com® --



I intend to use it on our stainless steel parts that come off the plasma cutter.
I use 304 SS and it has mill scale on it.
Here are the steps I currently use to finish these parts by hand. We use a 7" Dewalt grinder mounted in a vise to grind a bevel on the leading edge of the splitters and riving knives. We dress up the burnt edge a bit at this time too.

Then we move to a 6" x 48" belt sander. It is laying flat.
With gloves we sand the flat sides of these on both sides to get the scale off using 80 grit. That is very hard on the body. It takes quite a bit of down force to accomplish this. Then we move to a 1" x 30" belt sander and ease the sharpness off all edges.
Then it is back to the 6" x 48" belt sander with a 3M mesh belt to put a finish polish on them. Pheeew. Considering we do a bunch of these things every week, our necks and backs pay for it. ;(

Now to the project. The drum in this thing is very sloppy with regard to height.

Different spots on the table are different heights. That won't do. The machine weighs about 190 to 200 pounds, so a lot of cast iron hanging out there on nothing more than flat steel slides. You can easily lift up the outbound side.
What I want to do is use some linear rails in there instead. That will move the drum out a bit, but still leaves me room for the parts to be finished out. Anyone have any input as to what rails might hold about 80 pounds of cast iron rigidly enough to be more accurate?
I'm thinking 20 mm might be plenty. They probably won't be more than 10 or 12" long.
I'll know more when I get it apart.
I am also considering installing a third one on the outboard side. There will not be much call for a lot of adjustment with this. Probably no more than 1/4" of up/down travel will be needed.
Thanks for any advice or thoughts you might have.

[LeeWay]

Here is the part breakdown if that helps.


Those two long flat bars is what they are calling gibs. They are actually pretty thin. Maybe 5/16" by 5/8" or so. Maybe just beefing those up will do. Hmmm.

[LeeWay]

I could have bought drum sanders that have both sides secured. Like this one.
Grizzly.com® --



The reasons I didn't go for this is because all the table lifting mechanism and motors are down below. I do not think the stainless dust will be as easily collected from the top port, so I thought that might be a maintenance hog. I didn't really consider that I won't be lifting and lowering much at all, so now this seems like possibly a better choice.

Thinking about it and looking at the 12" model gives me another idea. If I can take some slop out by beefing up the gibs on the supported side, then what I really need on the outbound side is another threaded rod and handle to adjust and keep that height the same as the supported side. I could even install dro's on each side. Hmmm again. That sounds much easier. In fact, I have just the fine threaded rod and nuts here already.

[LeeWay]

Okay, guys. After studying this a bit closer, those gibs are very thin like I mentioned above. There is enough room there to just install some 1" by 3/4" flat bars. That should stiffen things up significantly.
I think this addition and the DRO's and another threaded rod on the open end should solve those issues cheaply. You know I have read a few complaints about these open end models having this type issue. Even the Performax. I do not see why they use such a small gib material.
I'll fix er up and let you guys know how it goes.


One other thing I noticed that I really didn't like. Look at part 259. It's the main yoke with the hand wheel attached.
Those two little tiny tabs on the side are what the entire motor and drum rides on. Talk about some weak points.

[SCzEngrgGroup]

Lee,

If it was me, I'd use at least 3/4" ACME rods - two at the right end, at least one at the left, and carefully fitted, plastic leadnuts on each (Turcite seems to work really nicely for this), with the screws supported by ball bearings at both ends. Then I'd remove the stock leadscrew for setting the height, and put a toothed belt, or chain, around all three Acme screws to raise and lower it. You'll never get height precision with the left end cantilevered as it is.

Regards,
Ray L.

[tmarks11]

that is thinking out side the box.

Have you tried muriatic acid?

For mechanical removal of scale, I have always been fond of using flap sanding wheels, which do a better job of taking off the scale without removing too much of the metal underneath.

How did the pieces look that came out of the drum sander? Is the problem that it is not taking off all the mill scale uniformly across the piece, or is it actually taking down the base metal underneath the scale>

[LeeWay]

Thanks, Guys.
You would think the drum would hang down, but it is actually up. You can push it down and lock it easily. Too easily. I like the idea of using chain. I have plenty of chain on hand. With the sprockets located somewhere above the yoke, changing the belting won't be any more difficult. High enough not to interfere. That sounds like a pretty accurate solution. Accurate enough for this anyway.

I haven't tried any acid. There is some burring from the plasma cutter, so some sanding is necessary. These parts need to be smooth on both sides with zero burr. The brushed finish I put on these always goes in the same direction that they would have wood passing by them when they are in the saw. That way they don't ever show any scratches. Oh and scratches are another reason that we sand these. The material I buy is usually drops and have some scratches. Even with film on one side, the other can have good scratches. They never line up with the brushed finish direction.

I still have the original 80 grit belt on this thing, so yes it is removing way too much material on the motor side and isn't even touching on the outboard side. I have only been running culled parts. I have some 180 grit bands on hand and will order some 240 grit.
That is likely all that is needed. The 3M mesh belt material may be all I need. The coarse variety of that stuff deburrs too. If that stuff will work, that will save us a lot of time as well as Icy Hot.

For testing I have been using a sheet of 3/4" marine grade plywood to run through the machine. Nice stuff.
I am using the drawer liner stuff for no slip, but that does not take heat well.
I will order some thin higher temp soft neoprene rubber sheet instead.

So, first things first. Drive both ends with synchronized screws.

I have a couple extra Thompson ball screws and nuts. They are 5/8". Hmmmm.

[SCzEngrgGroup]

I have a couple extra Thompson ball screws and nuts. They are 5/8". Hmmmm.

Lee,

Ballscrews might not be the best idea, due to the serious risk of contamination. I think Acme screws would work better long-term. Buy Acme screw stock from McMaster, then cut your own leadnuts using an Acme tap. Using a good plastic, like Turcite, will give you a nice, tight fit, with near zero backlash, and very smooth, silent motion, with no need for lubrication.

Regards,
Ray L.

[LeeWay]

I thought about that after I posted it. There really would not be an easy way to keep ballscrews clean. I do have some nice precision 3/8" acme screws here that have precision anti-backlash nuts, but I think they are too small.
I do also have a bunch of 5/8" acme screw here that I originally bought for my first router. They will need a bit of surface rust removal, but I am still coming out cheap I think.
I already made and used a tap out of some of it. Should make a nice 2" long lead nut pretty easy.
With the drum supported on both ends, I really don't need to beef up the gibs for that purpose, but I think it is a useful upgrade and may help eliminate any vibrations. I will also get a chance to see if some UHMW strips in between will be useful. That has got to be better than cast iron to cast iron.

[SCzEngrgGroup]

Lee,

A real Acme tap will give you a MUCH better thread than one home-made from Acme stock. I would recommend at LEAST 3/4" screws. The material is cheap....

Regards,
Ray L.

[SCzEngrgGroup]

Lee,

Congratulations! You've gotten yourself kicked to Siberia, where nobody will ever find or respond to your thread. How annoying....

Regards,
Ray L.

[LeeWay]

Right. I get two search results for drum sander in this forum. I knew the Novakon forum may be the wrong spot, but I guess I need to spend more time around here to figure out the right spot.
I was getting suggestions and answers just fine where it was. Now I'll have to pack a pistol in unknown territory.

[LeeWay]

Just to show what the finished parts look like, here's a couple images. This model is on a 1950 Delta Unisaw.

[LeeWay]

I looked into what you suggested Ray. I think I will have to go another route instead. I did pick up some Turcite though for future projects. Thats the stuff.

The area being lifted is very small really. Maybe 5" from one track to the other.
That motor mount/slide is also pretty oddly shaped as is the yoke. No real flat spots to work off of other than the original bearing seat. I ordered a 5/8" cast iron flange bearing for that spot.
I order 5/8" fine thread 18 pitch for the threaded rods for both sides. I think fine thread is actually better in this case so that I can fine tune the height.
I order two 5/8" pillow block bearings for the outboard side. I ordered some large threaded inserts too. The rod that adjusts the height right now is threaded into the cast iron tab. Much adjustment and those threads in the cast iron would be lost.
I ordered a couple 5/8" sprockets for the 35 chain too. I will have to build a frame for the outbound side, but should be able to use the original side as is with the new threaded rod.

I will say that the threaded rod on the main drive side is 15.5 MM fine thread from the factory. Too small to be 5/8"

Talk about an odd size. That is why I could not just put an identical one on the other side.

Oh and some parts of this machine cannot be ordered. Wow. You break it, you buy a whole new machine.

[engnerdan]

Sounds like a DIY "TIMERSAVER" project. That is what the sheet metal shops use to grind the surface of sheet metal or sheet stock.

Home | Timesavers


You have already spent the money so maybe this will be of no help. A while back I saw that Tormach has a belt sanding attachment for their surface grinder. It has some sort of compliant wheel so it can be used to sand/grind the surface of a piece of stock held in the machine. I saw a YouTub video from the Grismo Brothers showing them using it. It might give you additional ideas on how to clean up your parts.


-Dan

[LeeWay]

Thanks a bunch for the link, Dan. I wasn't really aware that they made so many different type metal finishing machines. I have installed several large belt sanding machines in a couple of furniture factories, so I know how they work.

I was limited by quite a few issues on trying to finish these parts. The shapes vary wildly from model to model. Pre brushing a full sheet is out because it would still require deburring after the plasma. Cost is also a factor, however if I would have known about Timesavers, the little machine they offer could have been financed.
I think what I am working on with this machine will do what we need though. I don't foresee any major issues at this point. I will keep you guys posted.

[LeeWay]

I managed to get this together yesterday and got to just about the last step of installing the roller chain. Now the chain I had on hand was 25P. I ordered 35P sprockets. Ouch. I should have the new chain this evening and continue to finish this up in the next day or two.I'll snap a few pictures.
There is absolutely nothing centered on this machine. The original screw is offset on the yoke. Everything on the open end is offset from itself.Nothing centered. This meant that I had to build it one step at a time.
It worked though.
I wound up using the same threaded yoke tab, but cut new threads in it to match the new rod that I used. The hole was quite a bit smaller, so that worked out great for now.
If that cast tab ever wears out, I left enough threaded rod to install a threaded nut below. Like I did on the open end. I basically built a yoke on the open end using angle iron and flat bar.
More to come.

[LeeWay]

As promised, a couple of images. Had some bronze hammertone rattle can paint left over from another project, so used it on the steel and the aluminum nut housing. I live in South Alabama about 20 minutes from the Gulf. As soon as I place a steel order online, it starts rusting. I used a key locking threaded insert in the nut housing. Works pretty well.
I did get the chain in. I need to calibrate the drum to the feed table.
I think I will use a linear bearing clamped across the feed table and a dial indicator. I can go across the top of the drum. Then I can adjust the chain tension a little with shims.
Grizzly claims this is a 1.5HP motor. I stalled it a time or two on the first testing I did. I was hogging off some material, but I don't know that it's 1.5HP. It says 1100 Watts, so should be close. The drum is direct drive with a spider coupler.
Anyway, I will get some testing done soon.

Oh and the dust cover just does clear the chain. That was luck.

[LeeWay]

I could have made the yoke narrower, but made it the same width as the original yoke. That was just in case I needed to add a joining brace between them in order to tension the chain. That was not needed though. The new yoke is rock solid. Can easily hold chain tension.
The base is 2" x 3" x 1/4" angle with 4 bolts holding it to the base. Uprights are 2" x 2" x 1/4". Top is 2.5" x 5/16" flat bar. I chose to bolt it together over welding in case I needed to change something.

[LeeWay]

Okay, the chain was easily tensioned correctly and leveling the drum was very easy. Just as I had anticipated. The conveyor belt on this machine is some sort of honeycombed plastic sheet. Not really slip resistant. The bend on it at the ends is no more than 3/4". I could put a chevron grooved rubber belt on it, but it may need slightly larger feed rollers. I think the smallest I saw was 1" bend. It will be easier to texture the bottom of our plywood sleds. The little 24 VDC motor that drives the conveyor is pretty strong though. It doesn't stall or slip under pressure. That is a plus.

I am still not quite getting the results I need. I think the pinch rollers are far too weak for one thing. Very weak springs. They do not help prevent part slippage at all. Another thing that this machine lacks that almost every other drum sander I have ever seen has is a rubber face on the drum. Right now it is just rigid aluminum and the sand paper attaches directly to that. Zero cushion. I think that may be another reason parts are shifting under the drum.
So I will work on adding an 1/8" rubber cushion on the drum and heavier pinch roller springs.
If this machine never is able to do our parts, at least I will have a very nice planer sander for woodworking with all the upgrades.

I did also contact Timesavers. I asked them for a quote on the single stage 1100 that does wet sanding. Depending on the footprint and cost, I may go that route if I can't make this one work for me.