I’m currently cutting an Evergreen styrene tube to form a concrete base stump for some lighting fixtures on my passenger station. I’m cutting them with a hobby knife through a hobby-sized mitre box. Thing is, all of the stumps have varying sizes, and none of them have perfectly flat ends. I know there has to be a better way of doing this. Any advice from ore experienced modelers would be helpful!
Hobby Knife? Normally a “razor” saw or hobby saw is used for cutting thick styrene material.
My problem is backwards to yours. I have a problem cutting anything straight.
I would suggest first using a fine cut saw, it’s a lot easier than a blade. I use Styrene for streetlight mounting, tree bases and a bunch of other things too. How about sandpaper? I normally have a sheet of 80 grit handy for leveling Styrene. I tack the sandpaper to my cutting matt with rubber glue and rub the object on it.
Mel
Modeling the SP in HO scale since 1951
My Model Railroad
http://melvineperry.blogspot.com/
Sorry, wrong use of words. I did use a hobby saw.
OK, next question - how much slack is there in the slots in the mitre box you are using - I find the average alumimum hobby mitre box has a bit of play in the slot with regard to the razor saw blade, so you can get slight angles in the cut. I have to push the blade to stay against the slot walls to keep it straight as I cut down, otherwise it seems to “wander” and gives an angled cut. Also, secure the piece being cut so it doesn’t get pushed back during the cutting process.
My sanding block (to straight the edges) is sanding film taped to a cheap glass hand mirror; as Mel mentioned there are other possibilities.
One absolutely frustrating item is the NWSL Tru-Sander. Really good idea in theory, and I brought one over a decade ago, which now gathers dust. Why? Because the guide edge (which has to be absolutely straight and vertical) at least back then was the edge of the flat masonite piece, and so after some sanding the edge would become angled, grooved, or erose, and so absolutely worthless. The correct edge would have been harden metal or wear resistant plastic, but back then it sure wasn’t. I’m sure you can find a post from a 10-year younger me ranting about that somewhere in the forum archives…
As chutton noted, decide which side of the slot in the box you’ll cut on. Don’t try to cut down the middle, it’ll never work.
Check your tools. I’ve pitched a well worn miter box from hobby use to the garage because the slot was wollered out. The boxes are aluminum, while the blade is steel, so the box will wear. The steel saw blade nonetheless will itself become worn, too, so old saws should be retired at some point.
If the tools are good, fresh, sharp, then check your technique. Use a light touch. Seems wrong, but that way the saw does the cutting, not your downward force. Make the force you apply to the cutting be side-to-side, while you keep a death grip on the material to hold it down to prevent it from sliding.
Speaking of sliding, if the grip is difficult or troublesome (arthritis, etc), then grab one of those floppy sheets of rubber or silicone they make to open jars with. The thin stuff works well to wrap around the piece and hold in place, although you must still be careful the material is square against the side of the box.
“Perfect” cuts can still be tricky. Get as good as you can with the saw, but if you leave a little extra material on one side, slide it to the end of the boc and use that as a filing square to get it straight as possible.
Chutton and Mike Lehman make valid points about the “sloppy slots” which eventually come to characterize such devices as the Xacto mitre box. Even when new, there is significant play when using a quality saw such as a Zona, in trying to get a straight 90 degree cut in flat, square or round styrene material using the Xacto box. I always spend more time truing the angle after the cut. I wish there was a zero clearance device or D-I-Y jig to make better truer straight cuts.
Cedarwoodron
I haven’t tried them, but Micro-mark makes a couple of hobby-sized chop saws that might fit the bill. The simple cheap one only does 90 and 45 degrees IIRC: http://www.micromark.com/microlux-mini-miter-and-cut-off-saw,9639.html
The fancy one has more flexible options: http://www.micromark.com/proxxon-mini-chop-miter-saw-for-hobby-use,8531.html
I have a Proxxon mini table saw, and as long as the cutting guide is set perpendicular, it does a good job. As with any power took cutting plastic, the cut is a combination of cutting and melting. There will be a bit of fililng or sanding to remove the melted plastic that sticks to the work piece.
I think the table saw is a bit more versitle tool than the chop saw, based on my full sized tools of the same type.
I don’t use a Mitre box if it can be avoided…especially on tube/rod, brass/styrene. I put it in a Pana Standard head hobby vise and set the cut edge right next to the jaws as a guide. The jaws have removable and replaceable jaws, Delrin plastic, brass, steel and aluminum. I use a Zona fine tooth blade for brass and a Medium wood cutting blade for plastic, that I take bar soap and rub the side of the blade and teeth with it. The animal fat in the soap makes the blade glide thru the cut easier and the wood blade will not fill up with plastic like a fine blade does. For larger wood, plastic’s and metal, I have a 4’’ inch blade table saw that I made a larger table base for with a precision guide and fence and usually use a diamond cutting blade for that. I learned many yrs ago…if You want a great job…then You better off starting with a great tool, so I don’t skimp when it comes to tools.
Take Care! [:D]
Frank
I use an ancient Ayers hardwood miter box to which I’ve added a couple of brass blocks, screwed to the top on both sides, more or less to guide the early cuts made with a jewelers saw, with a stop clamped to the near side of the box. Since the teeth angle backward, as in a coping saw, they hold the brass or plastic tubing down in the corners while pressing the end of the tube against the stop. I lightly cut a slight groove around the tube, letting the teeth turn it until I have a ring around the tube, making sure the groove is parallel to the end of the tube before deepening the groove all around until the blade is bedded. You have to be careful with brass tubing when the blade breaks through the wall, so you don’t snap the fragile blades, but that shouldn’t be a problem with styrene tubing.
I scratchbuilt my first O scale steam loco, a Mogul, over a cheap, reworked Japanese mechanism, back in the early days, in my 20s, and used this method to cut rings for the top of the stack and both lights, which were modeled using K&S brass tubing. Since then, I made thin rings and nice, square-ended tubing for engine brake cylinders and headlights, not to mention several stacks, in both HO and O. Funny thing is, using a jewelers saw and those 1/4" blocks, I’ve hardly ever scratched the faces of the blocks!
You have to be patient and have steady hands, but if you’re scratchbuilding and kitbashing, you probably already have lots of both commodities.
For bar stock of either brass, nickel-silver, or styrene, I use a Dobson Miter-Rite that was my first order to Micro-Mark, back in the mid-90s. Of course, being a model railroader, I had to modify it, mounting the miter mechanism on a longer piece of hardwood, provided a slot for a stop (I use a modelers clamp and a hospital IV tubing clamp, plus a brass bar, and can cut multiple pieces of anything from a 1/32" to 10" for ESM styrene stock, for lots of the underframe parts fo
One of the advantages of the old hardwood miter box was being able to cut a new slot. Then it exactly matched your saw. I have both an old Suydam model sized and a large miter box that I have done that to.
Enjoy
Paul
I’m sorry but I miss read your original post. I thought that you wanted crooked cuts, must be old age dinging my brain.
I use an Aluminum Mitre Box (Hobby Lobby) and as the slot widens from use I use slotted Styrene tubing to narrow the slot.
As the slot width increases over time I increase the Styrene tubing size or put tubing on both sides of the slot. The Mitre Box in the pictures is about 4 years old and the Xacto saw blade is somewhat tight but still cuts easily. When this slot gets wide enough for a second set of tubes it will keep the saw blade comfortable for many years, my last Mitre Box lasted over twenty years with Styrene sleeves.
THANK YOU!!! I SHALL TRY THAT!!!
[bow]
Mel’s the man! Great idea.
You can get one for around $35 at Harbor Freight, more like the first than the second one.
There are 2 items I use nearly every day: A full size $5 plastic mitre box from Home Depot, and a half dozen DeWalt trigger clamps:
While the box has perfect 90 degree corners inside, the whole interior is on a slight angle making it easier to work with. That creates about a 3/4 " ledge on the underside which is just as useful as the inside for use as a ‘stop’ or fense. Use the clamps to hold small stuff in place for cutting your small tubing. I think those clamps can exert 50 lbs pressure or more, vastly more than you need. I cut with a full-size hack saw with a 32 TPI blade. Never a problem.
I use the box to clamp 2 sides of a structure together for glueing, clamping one wall to the bottom and the other to the vertical side of the box. Perfect corners and nothing moves. Then you can pick the whole thing up without disturbing the bond, put it aside while the glue sets, and work on something else. Tip: line the inside corner of the box with a strip of foil if you’re using a weld type solvent so you don’t glue your structure to the mitre box.
Indispensable tools, for me.
Both RR_MEL and Paul have great ideas for helping with straight cuts. I will try Mel’s to nite and Paul’s is inexpensive as well. That’s what I like about this forum- others with solutions to problems. Well done, gentlemen!
Cedarwoodron