Author Topic: How to build this without cutting off my fingers...or other body parts.  (Read 4618 times)

0 Members and 1 Guest are viewing this topic.

Dave Schneider

  • Crew
  • *
  • Posts: 2377
  • Respect: +48
I am getting ready to start work on some new structures for the Beer Line, and am working on the large Schlitz grain elevator seen in this photo, which some call Elevator A.



This is the footprint for this building, and it is a straightforward design that can be mostly constructed with PVC pipe. However, there are a couple of places shown by the arrows where there are curved (decorative?) sections.



I have schemed up various ways to rip PVC pipe on my table saw to make these curved sections, but thought I should appeal to the collective wisdom of the group for better solution(s)....because this has the potential to end up in one of those "it seemed like a good idea at the time" moments. The outside diameter of these tubes is ~1.25 inches. Here is one thought. Cut, flip, cut.



Thoughts? Prayers? 911 on voice activated speed dial? Upgrade to one of those instant stop table saws?

Best wishes, Dave
If you lend someone $20, and never see that person again, it was probably worth it.

Lemosteam

  • Crew
  • *
  • Posts: 4339
  • Gender: Male
  • PRR, The Standard Railroad of my World
  • Respect: +1448
    • Designer at Keystone Details
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #1 on: January 22, 2013, 08:32:22 PM »
0
Dave,

I would only attempt this once so make sure you have enough length for both pieces.   

It appears that you are cutting 1/4 of the pipe out (from the drawing).  I would make a right angle cradle as you have drawn but instead of using a bolt, I would put two strips of double stick tape 90 degrees apart in the cradle and stick the pipe into the corner of the cradle.  Use the cradle for pushing the part, not the pipe.

Raise the blade so it cuts down more than forward (but not through the top) so the force wants to keep the pipe in the cradle rather than pushing it forward.  Then run the blade right down the middle, perpendicular to the table.  Turn the slider around and rotate so the just cut side is against the fence and rip the 90 degree portion out.  Watch that the remaining piece does not fall into the blade.

I have used double stick tape to attach router patterns without fail.

John

  • Administrator
  • Crew
  • *****
  • Posts: 11233
  • Gender: Male
  • Respect: +801
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #2 on: January 22, 2013, 08:33:36 PM »
0
Use the PVC as a guide, then take a piece of styrene - heat it with a heat gun, mold to shape, trim off extra .. and keep your fingers :)

PJPickard

  • Crew
  • *
  • Posts: 86
  • Respect: +2
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #3 on: January 22, 2013, 08:39:44 PM »
0
As someone who has spent a lifetime doing similar work in prototype modelmaking I think you have  a decent solution.  You have to keep in mind and imagine that this tube will bow out as it gets cut. A lot. Think about how that will play out as the cut is made. Sometimes it is fine other times you will wind up with a binding situation.

One thing I used to do is hot glue the tube to a piece of wood, easier than all the bolting.  Once you have one cut the next can be done fairly easily as you mention.

Another idea I thought of is if you slit the adjacent tubes, you might be able to slip in the partial ones without all the fancy cutting.  They enter at pretty much 90 degrees, so you would need to slit 2 tubes and maybe just one tube in half to make the configuration.

As a machinist and modelmaker, sometimes you can spend hours building the fixture to make the cut that  takes 2 mins. Its almost always worth it, over some shortcut.

I assume you are doing this on a full size saw.  Go slowly, very slowly to avoid melting the material. 

Your beer line model is great BTW.

Paul

Philip H

  • Crew
  • *
  • Posts: 7823
  • Gender: Male
  • Respect: +690
    • Layout Progress Blog
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #4 on: January 22, 2013, 08:44:17 PM »
0
If it were me, I'd build a 90 degree cradle. Use either hot glue or double sided tape. And then run it through a bad saw. That way you make one cut per piece instead of 2 and you get your cradle precut for the next one.  As an alternate, get some hard wood dial stock the right diameter, set your rip fen e really tightly and well measured, cut the dowel, then follow John's approach to shape styrene.
Philip H.
Chief Everything Officer
Baton Rouge Southern RR - Mount Rainier Division.

"Yes there are somethings that are "off;" but hey, so what." ~ Wyatt

"I'm trying to have less cranial rectal inversion with this." - Ed K.

"There's more to MRR life than the Wheezy & Nowheresville." C855B

LV LOU

  • Crew
  • *
  • Posts: 620
  • Gender: Male
  • Respect: 0
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #5 on: January 22, 2013, 08:46:14 PM »
0
 Dave,make a guide that's just a single,wide,flat piece of wood,not an angle.The second piece lifts the whole thing up,exposing a lot of blade,making it VERY dangerous.Do your bolt idea,but instead of pushing it through with the bolt,bolt it right to the piece.setup your rip fence/blade so you get the blade as low as possible to JUST make the cut..I might even consider trying to get the blade angled out from the fence,not into the fence as you show it,so it's nowhere near you hand..And,don't be cheap with the pipe.The best way to cut these thing without getting hurt is to never get near the blade,so use the pipe as a handle,don't cut it to length before cutting,do it after.You could even tap a bolt into the top/front of the pipe to use as a handle so you're holding the bolt,not the pipe..

kalbert

  • Crew
  • *
  • Posts: 459
  • Respect: 0
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #6 on: January 22, 2013, 08:50:00 PM »
0
I have tried now several times to cut PVC pipe to make silos. For me hands down the best way is to rub the sides of the segments on a belt sander to make a flat spot 1/4 inch wide or more and using liberal amounts of regular old PVC glue to bond the flat surfaces together. Most concrete silos share interior walls to some extent, and making the flat part wider might be necesary to get the right look. This makes a fairly strong bond that can be broken if you try hard enough but why would you try that hard to break your silos apart? I have also had good luck bonding pipes to blocks of wood by roughing up the PVC pretty good with sandpaper and using very liberal amounts of Powergrab.

Now... for this one, I'd say use a block of wood with the correct angle in the middle, flatten pieces as will touch the wood or eachother just a bit, and stack the silos on the end like this, then use some globs of Powergrab in the voids between silos and wood:



EDIT: Oops I see I got carried away with the eraser on the lower right silos. You get the idea though. The very bottom one should be a complete unit.
« Last Edit: January 22, 2013, 08:56:01 PM by kalbert »

DKS

  • The Pitt
  • Crew
  • *
  • Posts: 12272
  • Dead Man Modeling
  • Respect: +3791
    • David's Modeling Journey
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #7 on: January 22, 2013, 09:06:58 PM »
0
This would be a simple thing to cast in resin. Make just one (or, in this case two, one of each type), make a mold, and cast as many as you need. Just a thought...
“Everyone leaves unfinished business. That's what dying is.” —Amos, The Expanse

up1950s

  • Crew
  • *
  • Posts: 9117
  • Gender: Male
  • Respect: +1001
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #8 on: January 22, 2013, 09:46:00 PM »
0
" Go slowly, very slowly to avoid melting the material. "

Fill the tube with tightly packed wet sponges , freeze , fasten , cut , thaw , then season to taste .

That may cover flex , heat , fastening compression , and thirst .

Just guessing about this .


tom mann

  • Administrator
  • Crew
  • *****
  • Posts: 10827
  • Representing The Railwire on The Railwire
  • Respect: +888
    • http://www.chicagoswitching.com
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #9 on: January 22, 2013, 09:50:26 PM »
0

Ian MacMillan

  • Global Moderator
  • Crew
  • *
  • Posts: 11938
  • Gender: Male
  • Learn to use the god damn search feature!
  • Respect: +69
    • Conrail's Portland Line
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #10 on: January 22, 2013, 10:44:11 PM »
0


This is the footprint for this building, and it is a straightforward design that can be mostly constructed with PVC pipe. However, there are a couple of places shown by the arrows where there are curved (decorative?) sections.





Oddly for that one "wall" you could use the Walthers Medusa cement kit and keep yar fingers! But then you have to buy the whole damn kit for that one wall.
I WANNA SEE THE BOAT MOVIE!

kelticsylk

  • Crew
  • *
  • Posts: 781
  • Respect: 0
    • Milepost 15
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #11 on: January 23, 2013, 01:20:28 AM »
0
You could replace your table saw blade with an abrasive disc (aka metal cutting disc) and use it as a sander. For the decorative parts I would rip the pipe in half using the blade and then use the disc as a sander to get it down to the correct size. Feed slow. There's more waste this way, but you save your fingers. Beside what would you use the small arcs of pipe for? Ground up as "sawdust" the waste can be used for some sort of scenery material like trees or bushes (piles of snow?). Dissolved in the PVC glue the particles might have quite a few applications as filler for all kinds of things.


Dave Schneider

  • Crew
  • *
  • Posts: 2377
  • Respect: +48
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #12 on: January 23, 2013, 02:12:57 AM »
0
Thanks for the suggestions everyone. I am really attached to my fingers and am committed to keeping them. Some good alternate ideas here. I like the ideas of heating styrene or some other plastic and bending it or casting the partial curve. I think I will try these first. Sanding is another idea, but I don't have a disk sander, and this seems rather messy and laborious. A bandsaw is another good idea, but I don't have one of those yet.

Tom, thanks for the hipster logo. This was the last logo on Elevator B, the funky angled building in my first photo. It had a variety of logos over the years.

1942


1945


1963 (the worst....by far).


Late 1970s.


Between Pabst and Schlitz there were 4 grain elevators in an area smaller than a city block. Lots of thirsty people and alot of malted barley!

Best wishes, Dave
If you lend someone $20, and never see that person again, it was probably worth it.


havingfuntoo

  • Crew
  • *
  • Posts: 322
  • Gender: Male
  • Respect: +13
Re: How to build this without cutting off my fingers...or other body parts.
« Reply #14 on: January 23, 2013, 06:31:39 AM »
0
If you are going to use a table saw (circular saw) rather than a band saw, put the blade in backwards. I always use an abrasive disk in a circular saw rather than a saw blade for cutting plastic pipe, and for drilling holes in plastic pipe I use wood bits, they shave rather than cut. You might want to look a diamond tip blade, they are more rigid than some of the abrasive disks.