Scratchbuilding Sawmills

[JeffB]

My source for laserboard is here:

https://encompass-media.salesvu.com/

Sells it in 12"x24", various sizes. Also sells other laser materials.

Sam

Thanks Sam, that's exactly what I was looking for!

About 5 years ago I bought small sheets of Polybak on ebay. They were a little larger than 8.5x11, but shipped in a cardboard envelope.

https://www.ebay.com/itm/164536925742

Says he has other thicknesses, but couldn't find them.

Thanks Chris... 

Jeff

[JeffB]

What size would be convenient for you??? and how many do you want??? I had read on another forum that Richland Industries will ship 4X8 sheets rolled up in a tube and shipping was around $15. 
 I've done the same for windows and trim pieces and didn't like the outcome. That why I started printing them long ago, first with the FDM printer and now on the Photons.  I've tried brick on plywood and didn't like the way it turn out. I experimented with acrylic on the old K40 laser I had, and it was way better that the wood trial I'd tried. I did my sugar warehouse out of .062" acrylic on the new 100 watt laser I just built. Here is a closeup of the brick detail. 

Sam provided a link that I can buy smaller sheet sizes from, so I'll give that a go instead.  But thank you for the offer!

I could see where brick on birch plywood wouldn't work, plywood has its quirks when laser cutting.  I was going to give bricks a go on some acrylic sheet.  I have some 0.08" thick stock, which is the perfect thickness for making brick sheets that interlock at the corners (cause my bricks are about that long).  If that works OK, I'll have to source a different acrylic material as the stuff I have cuts fine, but stress fractures at the etch and cuts lines like crazy.

So you built yourself a 100W machine?  Nice!  Share some photos of it if you don't mind...  Been in the laser cutting field for about 29yrs now.  Thought about building my own system, but decided on buying one of the larger machines on ebay (12" x 20" work area, 50W laser).

Jeff

[rodsup9000]

So you built yourself a 100W machine?  Nice!  Share some photos of it if you don't mind...  Been in the laser cutting field for about 29yrs now.  Thought about building my own system, but decided on buying one of the larger machines on ebay (12" x 20" work area, 50W laser).

Jeff

 Here is what I got. It has a 22"X38" bed, 100 watt RECI tube (made before they started selling rejects to other manufactures in China). I also have a true 50 watt tube (sold as a 60 watt) that I can switch out when I want finer kerfs. I have 2 fume extraction fans on it. One is hooked up directly to bed to make a vacuum table and the other one for the whole cabinet extraction.

 Here is a buildlog that I did as I built it.
https://rdworkslab.com/viewtopic.php?f=159&t=5526

[JeffB]

Here is what I got. It has a 22"X38" bed, 100 watt RECI tube (made before they started selling rejects to other manufactures in China). I also have a true 50 watt tube (sold as a 60 watt) that I can switch out when I want finer kerfs. I have 2 fume extraction fans on it. One is hooked up directly to bed to make a vacuum table and the other one for the whole cabinet extraction.

Damn impressive Rod!!  I read through all the build posts in the link you sent...  I'd consider building one if I had a larger mill and lathe, but mine are too small to make the parts necessary for such a machine.  Maybe in retirement, when I hope to buy larger machine tools for my shop. 

That you can do this sort of thing now days, with off the shelf components, is pretty darn incredible... 

I like your fume/smoke exhaust system.  I rigged up my machine with a booster fan, but it's just a small HVAC 6" duct fan, which does help, but doesn't provide a lot of draw.  Just enough to help boost the exhaust provided by the fan on the back of my machine (which is a good sized high flow/speed PC case fan by the looks of it). 

For a smaller kerf, I purchased a compound lens assembly (two focusing optics) from Cloud Ray, on the recommendation of the guy that designed it.  I wanted a super narrow laser kerf for cutting my own shingle stock.  The standard lens has a kerf of about 0.008" when I take a lot of time to find the absolute focal point.  The compound lens cuts that down to about 0.004"-0.005" and when I use a small leveling table on the machine (which I built myself) that kerf width is consistent over the whole working range. 

The compound lens assembly works really well and is not a very expensive upgrade, though it is a process to go from one set up to the other.  The only other downside is that the nozzle height for the compound lens assembly is about 2.5X that of the standard lens.  Which basically means you don't get the same effect from the cutting gas (compressed air for most) pushing the vaporized material through the kerf.  But I only use it for shingle stock, which is about 0.005" thick, so it's not so much of an issue.  I cut/etch all other materials using the standard set up.

Thanks for sharing the photos of your machine and the link to the build...  It is a fascinating project that has me thinking!

Jeff

[rodsup9000]

Damn impressive Rod!!  I read through all the build posts in the link you sent...  I'd consider building one if I had a larger mill and lathe, but mine are too small to make the parts necessary for such a machine.  Maybe in retirement, when I hope to buy larger machine tools for my shop. 

That you can do this sort of thing now days, with off the shelf components, is pretty darn incredible... 

I like your fume/smoke exhaust system.  I rigged up my machine with a booster fan, but it's just a small HVAC 6" duct fan, which does help, but doesn't provide a lot of draw.  Just enough to help boost the exhaust provided by the fan on the back of my machine (which is a good sized high flow/speed PC case fan by the looks of it). 

For a smaller kerf, I purchased a compound lens assembly (two focusing optics) from Cloud Ray, on the recommendation of the guy that designed it.  I wanted a super narrow laser kerf for cutting my own shingle stock.  The standard lens has a kerf of about 0.008" when I take a lot of time to find the absolute focal point.  The compound lens cuts that down to about 0.004"-0.005" and when I use a small leveling table on the machine (which I built myself) that kerf width is consistent over the whole working range. 

The compound lens assembly works really well and is not a very expensive upgrade, though it is a process to go from one set up to the other.  The only other downside is that the nozzle height for the compound lens assembly is about 2.5X that of the standard lens.  Which basically means you don't get the same effect from the cutting gas (compressed air for most) pushing the vaporized material through the kerf.  But I only use it for shingle stock, which is about 0.005" thick, so it's not so much of an issue.  I cut/etch all other materials using the standard set up.

Thanks for sharing the photos of your machine and the link to the build...  It is a fascinating project that has me thinking!

Jeff

 Jeff,
  I sent you a PM

[samusi01]

Rodney,

That’s an impressive setup you’ve got. I was thinking about power settings yesterday. As I noted, I use a 40w
laser but one can set the power setting when sending the job to the laser. As an example, when working on small parts on the 0.011” stock, I usually use between 20 and 25% power as the higher settings simply destroy smaller parts. I imagine your setup has something similar? My experience is the kerf varies depending on power setting and material.

Sam

[rodsup9000]

Rodney,

That’s an impressive setup you’ve got. I was thinking about power settings yesterday. As I noted, I use a 40w
laser but one can set the power setting when sending the job to the laser. As an example, when working on small parts on the 0.011” stock, I usually use between 20 and 25% power as the higher settings simply destroy smaller parts. I imagine your setup has something similar? My experience is the kerf varies depending on power setting and material.

Sam

  Sam,
  Thanks, as I've said before, I just enjoy building toys that I can use. 

  Yes, I can adjust the power in setup or on the fly and your right, if too much is used, it'll burn your work. Too little and it won't cut all the way through.
 

 I have a compound lens that Jeff talked about, but have yet to try it. I think it should work great for getting the kerf down to what I want for the siding on the sawmill. If I cannot get the PolyBak to look like wood, I'll have to buy some 1/64" plywood (expensive) for the siding.

[rodsup9000]

  As usual, I screwed up. I deleted one of the modified sides by mistake and cut out the wrong one, and didn't catch it till I already cut the parts out.


  I spent a couple of hours on laying the parts out to cut, trying to minimize the stock it take. 






 And the parts on the laser





And here the parts




  I got in a hurry and forgot to add the mortise and tenons to put the pieces together. Next to impossible to get everything square and even without them. These parts will go in the scrap bin for now.  It usually takes me 2 to 3 tries before I get good fitting parts and everything works as it should. 

[samusi01]

Why not cut a base out of scrap that is the size of the interior dimensions? Something cheap(ish) like 1/8” hardboard or similar. It can be used to align the parts and then, once assembled, the frame can be lifted free of the base.

The step I use between layout out parts and cutting them is to import the drawing into Fusion as a dxf file, extrude them to the appropriate thickness, and then literally build the object in Fusion from a clean sheet. Helps me find errors in the design and figure out ways to assemble the parts.

These parts are large enough to not have an issue, but with smaller parts I’ll gap the outermost line so the parts stay attached to the material. Prevents the loss of window frames and whatnot to the vacuum table. One thing I have noticed is, as parts get thinner and longer, they tend to move during the job and having tabs helps mitigate that.

Sam

[rodsup9000]

Why not cut a base out of scrap that is the size of the interior dimensions? Something cheap(ish) like 1/8” hardboard or similar. It can be used to align the parts and then, once assembled, the frame can be lifted free of the base.

The step I use between layout out parts and cutting them is to import the drawing into Fusion as a dxf file, extrude them to the appropriate thickness, and then literally build the object in Fusion from a clean sheet. Helps me find errors in the design and figure out ways to assemble the parts.

These parts are large enough to not have an issue, but with smaller parts I’ll gap the outermost line so the parts stay attached to the material. Prevents the loss of window frames and whatnot to the vacuum table. One thing I have noticed is, as parts get thinner and longer, they tend to move during the job and having tabs helps mitigate that.

Sam

 I usually 3D print the bases for my structures, but I'm going to try to build this one without one. I'm learning all the time about what works and what doesn't. I have the tools needed to put it together the way it is, but If I ever wanted to make a kit to sell, I might as well fix it now.

 The thing is, I built it 3D and didn't see the mistakes. I got the wall fixed and almost done adding tabs and slots on all the corners. I gap most of my stuff too.

[rodsup9000]

 Here what I have now. Still need to make the floors.


 

[MK]

Wow!!  You can leave this as-is on a layout, throw some construction materials around it, and call it "a building being built".

[JeffB]

  As usual, I screwed up. I deleted one of the modified sides by mistake and cut out the wrong one, and didn't catch it till I already cut the parts out.

  I spent a couple of hours on laying the parts out to cut, trying to minimize the stock it take. 

  I got in a hurry and forgot to add the mortise and tenons to put the pieces together. Next to impossible to get everything square and even without them. These parts will go in the scrap bin for now.  It usually takes me 2 to 3 tries before I get good fitting parts and everything works as it should.

Looks great Rodney!

Don't worry (not that you are), you're not the only one that screws up things and takes a few tries to get it right!  I'm usually good for about the same number of tries before I get something dialed in.

I keep telling myself that I should design the parts in 3D, but have been sticking with 2D CAD for the laser cut stuff (I use Solid Works for locomotive mechanism design).  But I've not bothered up to now...

I've been cutting parts from "chip board" lately, which is more or less thick cardstock (0.062" thick), though some suppliers pass it off as thin MDF.  It comes in 15" x 24" sheets and at about $3 a sheet, and it is a lot cheaper for proofing laser cut parts than basswood or birch ply!  Same can be said for screwing up parts in clapboard siding material...  That gets expensive really quick, especially if your using 6" wide sheet material. 

I get it at my local art supply store, which also has it 0.040" and 0.080" thick sheets.

Jeff

[JeffB]

Rodney,

That’s an impressive setup you’ve got. I was thinking about power settings yesterday. As I noted, I use a 40w
laser but one can set the power setting when sending the job to the laser. As an example, when working on small parts on the 0.011” stock, I usually use between 20 and 25% power as the higher settings simply destroy smaller parts. I imagine your setup has something similar? My experience is the kerf varies depending on power setting and material.

Sam

I always select a power level that gives me the best results...  Usually a combination of power and feedrate that results in the smallest kerf (width of the laser cut) and good geometric accuracy.  Because I'm not doing this as a source of income, time is generally not a concern when cutting parts.

Most of the materials and thicknesses we use (at least in HO or N scale) are pretty thin and don't require much laser power at all to cut and much less to scribe/engrave.  As you or someone else mentioned, increasing the laser power generally increases the kerf and shifts the focal point of the laser accordingly. 

It takes some experimentation and "playing" with your machine to get things dialed in, but once you get used to that, you can come up with some really good results consistently.  I guess it's like anything else, practice makes perfect.

Jeff

[rodsup9000]

   While searching for more information on sawmills, I found 2 photos of the Graeagle mill (.4 miles from the Blairsden station) that I'm trying to model. Now that I have the photos, I'm starting over. Here is the best photo of the two I found. Found it on a website about the history of Graeagle.

 




 The power house appears to be masonry. Notice the odd roof line of the main building. The left side has two different angles on it and they are different than the one on the right. 



 This came form "UC Davis Library"


 




 Working on the main mill building to get a good resemblance of the original mill.