I'm trying to determine the appropriate rotary cutting wheel size for modifing a peco n scale code 55 turnout frog. I'm using electrofrogs and I'd like to isolate the frog to power the frog with a tam valley frog juicer. I tried a cutting wheel that was too large and damaged the outside rails. Any suggestions? Also are there cutting jigs out there that help prevent damage to the areas you don't want to cut?
I suspect you are trying to use those Dremel EZ-Lock 'thin cut' wheels, which are 1.5" in diameter. This family of products gets around the problem with the old small thin cutoff wheels that have much smaller diameter that you can't cut rails 'parallel' to the thick body of the tool unless at an unworkable angle, and without imposing enough twist or lateral force on the cutting disk to make it fracture -- which it will easily and enthusiastically do at the drop of a hat. But the larger radius makes it impossible to 'drop in' to cut one rail where another is adjacent ... as in switches.
I suspect your answer is going to involve making a fixture, and here are the lines along which I suggest you think. What you want will be driven off a flexible shaft, or perhaps an angle head, not the rotary hand tool itself, so you can use thin-kerf small-radius cutting disks at true right angle to long runs of rail in track. You then want a jig that allows a perfect straight-down plunge cut onto the top of the rail being gapped, with controlled downfeed, arranged so your eyes and hands are not in the 'propeller arc' of the disk so that cutting dust or flinders from the inevitable fracture at the necessary rpm for correct surface cutting speed on the smaller disk will not hurt you.
I don't think there is a way of making the equivalent of a 'fence' to prevent adjacent rail damage, but you could temporarily provide a thin 'feeler' of sheet metal that would give you audible feedback if the feed got deep enough for the radius to interfere...
You might not have enough horizontal clearance for even a small disk if gapping close to a frog. In that case you might have to 'take your lumps' and cut straight across adjacent rails and then re-connect their ends electrically with feeders or bonding wires or brazing fill in the cut.
From time to time I have thought about adapting one of those vibratory hobby tools to take a very short length of thin-kerf razor or track saw blade, and patiently 'let the tool do the work' with carefully straight downfeed.
First, do the gaps NEED to be closer to the frog? If you can just use insulated rail joiners for the frog side of the diverging routes, that's a gap and you'll be in good shape in getting about as physically close as you can to the actual frog.
Mike Lehman
Urbana, IL
The Dremel 575D Right Angle Attachment really helps, then you can use smaller diameter cut-off blades. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
I use a flex attachment for my dremel that is about 5/8" in diameter, then I can cut rail perpendicular.
-Kevin
Living the dream.
Yeah, the right angle attachment would be the way to get a vertical cut in the rail using the cutoff disc. Based on my experience, the gap might be a little wider than I would like but I suppose if it is filled in and cut smooth, it would be ok.
I'd stick with the method of using insulated rail joiners instead of cutting rail per what Mike said.
Rio Grande. The Action Road - Focus 1977-1983
I took a picture of my flex shaft rotary tool.
It is a Dremel Advantage drywall rotary saw with the flex attachment. This is about 20 years old, and I do not know if it is still made or not.
This is a great tool. It has a 10 step speed control that goes from real slow to real fast.
With a 1 1/2" cut off wheel at the slowest speed it does an excellent job of cutting rail gaps.
I do use insulated rail joiners as a preference when possible.
SeeYou190I took a picture of my flex shaft rotary tool. It is a Dremel Advantage drywall rotary saw with the flex attachment.
There are aftermarket shafts that can be used to convert 'regular' Dremels to handpiece operation. These don't provide anywhere near the torque that the 'specialized' version can develop, but I can't imagine even the smallest of them would have trouble with making a thin-kerf cutoff wheel effective in rail cutting.
If you already have a Dremel, a flex shaft is available. One source is: https://www.micromark.com/Dremel-Flex-Shaft. Note that it will not fit all Dremels, especially the older ones. Dremel has a cross reference site.
Then you can use the small cutoff wheels. A source for these is: https://www.micromark.com/Emery-Cutting-Wheels-15-16-Inch-Dia-Package-of-72.
Note that these shatter easily. I am told a way around this problem is to coat the disc with CA and let dry before use. Have not tried that myself. In any event, safety glasses are mandatory.
While I do have a Dremel, it's an older single-speed model, so I generally prefer my Jobmate. When using it in the workshop, it's usually hanging from an upper shelf, with the flex-shaft attached and when using it in the layout room, I simply hang it somewhere convenient and again use the flexshaft.
When cutting gaps for electrical isolation, the cut doesn't have to be perpendicular to the ground, so not having a flexshaft shouldn't be an impediment to that task. Once the gap has been cut right through, I insert a small square of grey ABS plastic into the gap, then secure it with ca. Once the joint has harden, use a knife to remove the excess material. After the rails have been painted, the gaps will be almost invisible...
Wayne
There is another very effective method. I used a manual jeweller's saw with a fine toothed blade to cut my gaps. You have to disconnect the blade from one end of the 'harp' and then feed the loose end of the blade through the turnout ties in the appropriate location. Then reinstall the blade in the harp and with a few strokes you will have a nice gap in the rails.
https://www.micromark.com/Jewelers-Saw
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
doctorwayneWhen cutting gaps for electrical isolation, the cut doesn't have to be perpendicular to the ground, so not having a flexshaft shouldn't be an impediment to that task.
Yes, agree that the cut does not need to be perpendicular. Problem with using the usual Dremel with the large diameter body is that when one gets close enough to make the cut one's hand contacts the surface first. Then as the cut is being made the disk rotates through the cut and normally shatters.
I model in HO but I use a Dremel right angle attachment it helps with getting the cut off wheel at a better angle & takes the bulk of the tool out of play
https://www.walmart.com/ip/Dremel-575-4-inch-Right-Angle-Attachment-for-Rotary-Tools/1218361?wmlspartner=wlpa&selectedSellerId=795&&adid=22222222227018565139&wl0=&wl1=g&wl2=c&wl3=40873369952&wl4=pla-54837802853&wl5=9014246&wl6=&wl7=&wl8=&wl9=pla&wl10=112562476&wl11=online&wl12=1218361&veh=sem&gclid=EAIaIQobChMI4-e768is6wIV3h-tBh06awChEAQYAiABEgLHwfD_BwE
I am just disgusted with myself for not having seen what Wayne and Dave have pointed out: that narrow-kerf cuts are not really necessary and that cutting doesn't need to be from the top down or under power.
What I wonder now is if rotary power tools are really the 'better' solution ...whether for instance a thin flexible jeweler's coping blade,the kind that is a thin flexible abrasive rather than like a teeny-tiny piece of bandsaw blade, couldn't be passed under the rail and then worked in a loop from handles at the both ends, taking care not to pull up on the tool hard enough to pop the rail off or distort it. After just a couple of cuts the channel into the base of the rail should make the cut self-locating, and the work could then progress relatively blind from well above the layout with the only worry being the metal dust from the cutting and full integrity of 'separation' being assured with pullthrough ... and very good positive separation from nicking adjacent rails or other structure.
A jeweler's saw is the tool recommended by Fast Tracks for sawing gapes int he rail when making their turnouts. Works great as long as you are doing this before the turnout is installed - then you can do as Overmod mentions and unhook the blade from the frame, pass it through next to the frog, connect it back in the frame, and saw away.
If the turnout is already in place, the flex shaft on the Dremel is the way to go, to be able to use the smaller cutoff wheels and still get parallel to the rails with the handpiece so the blade is nicely perpendicular.
I remember the ads for the old Fordham motor tool. Dreme's been around for longer than a lot fo peoe think though as well,. and while the current felx shaft attachment might not work for some of the older Dremel tools, they had a flex shaft way back when for the older models. And mine, like Kevin's in the picture, still has a hook to hang it. I have the drill press, and it also has a hook on the top of the vertical beam to hang the tool when using a flex shaft.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I think some are losing sight of the fact that the OP wants to cut a gap in an N scale turnout. I don't see how jewelers saw blades will fit under the rails of an installed N scale turnout, nor how any sawing motion in an upward direction will result in anything other than ripping the rails from the ties.
I think even the back and forth motion of a razor saw would need to be monitored carefully to avoid damaging the turnout.
There is also the matter of clearance between the tool and the surroundings. The smallest tool capable of doing the job is the one that should be used.
If you do need tiny cutting discs, save old ones for this purpose before they're completely spent. I always have a few small ones rattling around in the Dremel kit for just this purpose.
maxmanI don't see how jewelers saw blades will fit under the rails of an installed N scale turnout,
Hi maxman,
I reread the OP's original post and I didn't see any reference to the turnouts already being installed. Maybe I missed something. You are certainly correct that a jeweller's saw won't work if the turnout is already installed.
mlehman If you do need tiny cutting discs, save old ones for this purpose before they're completely spent. I always have a few small ones rattling around in the Dremel kit for just this purpose.
hon30critterHi maxman, I reread the OP's original post and I didn't see any reference to the turnouts already being installed.
Maybe an assumption on my part. I couldn't figure why he would want to put gaps in an uninstalled item.
maxmanI couldn't figure why he would want to put gaps in an uninstalled item.
He wants to power the frog separately so he can control polarity with a Tam Valley Frog Juicer. Isolating the frog is a pretty standard procedure for Peco Electrofrog turnouts.
hon30critterHe wants to power the frog separately so he can control polarity with a Tam Valley Frog Juicer. Isolating the frog is a pretty standard procedure for Peco Electrofrog turnouts.
Yes, got that part. But the frog is pretty well isolated until such time that some track is connected to the frog end of the turnout. As others said, a couple insulated rail joiners would accomplish said isolation unless track was already laid.
maxmanBut the frog is pretty well isolated until such time that some track is connected to the frog end of the turnout. As others said, a couple insulated rail joiners would accomplish said isolation unless track was already laid.
My understanding (limited as it may be) is that the closure rails on the Peco Electrofrogs are connected to the frog rails. More recent models have gaps already cut between the frog and closure rails but there are jumpers that must be removed in order to isolate the frogs. Older models did not have the gaps with jumpers, so the track had to be cut. I have a bunch of older HO Peco Electrofrogs where I had to do that in order to make them DCC friendly.
Here is what I have used as a reference for wiring the turnouts:
http://www.wiringfordcc.com/switches.htm