Joe, that is a great tip no

Joe, that is a great tip no pun intended. Finding a better way always begins with realizing there is room for improvement in the old way. That step gets past many.

I'm not sure I see the point

I'm not sure I see the point of this article. Joe states right up front that "...there is nothing wrong with a slanted gap..." and I think that's very true. So what if the gap is at 75 or 80 degrees, rather than perpendicular to the rail?

This looks like a solution trying to find a problem.

Knowing that such a large cutoff wheel is available may be useful in itself, but as for it being an "Ah-Hah moment" for rail gaps, I'd say it missed the boat. More of a "Ho-Hum Moment" this time around.

The big benefit I see from

The big benefit I see from having the vertical gap instead of the gap at an angle is the elimination of the sharp point on the top of the rail that can grab things like cleaning wipes, track cleaning cars etc. A blunt rail is less likely to grab things. Now it is not a huge revolution but it does add a benefit. It also makes it easier to dress the rail ends with them in a vertical plane, again not huge but very helpful if you go to the trouble to do those things. It also makes the rail ends more durable when expansion and contraction issues raise their heads and joints close up and may in fact become tightly forced together. The later is more likely on a large layout in an area that is subject to humidity swings that affect the wood support structure.

Doing things like that show more benefit to someone running long trains rather than short trains. The long trains do to the greater forces involved seem to find any excuse they can to leave the rails. This is just one more way to eliminate some possible issues.

"sharp point on the top of

  Hi Rob, I cut my gaps with a dremel, they end up slanted maybe 15 degrees off plumb. I found that some old HO scale plastic roof walk material is a perfect thickness for filling the gaps so I nip off a piece with my Xuron cutters and glue it in then smooth it when dry and no problems with anything snagging on the gap.....DaveB

Digging deeper

First let me say I’m not naive enough to expect every Ah-Hah moment to be useful to all readers.

That said, let’s assess these two pages for useful content.

1. Gives the link to an awesome assorted set of diamond cutoff wheels that will outlast the easy-to-break composite cutoff wheels many times over.
2. Gives suggestions for using the right angle attachment and/or the flexible shaft attachment to give you many more tool angle-of-attack options.
3. Gives the link to a jumbo-sized set of six diamond cutoff wheels for about $1 each — a bargain.

Points 1 and 2 are very general purpose and will help in lots of motor tool use cases beyond just cutting rail gaps. If you can extrapolate the suggestions beyond the narrow example given, there’s gold in them thar two pages.

Now, as for vertical gap cuts vs slanted gap cuts ... neatness counts. Electrons don’t care if your wiring is messy or tidy, but any electrical guy will tell you it pays to be tidy.

A room that’s not built square is just as livable as a room that’s built square, but any carpenter worth his salt aims to build the room square. 

My biggest gripe with non vertical rail gaps is that I prefer to have the option to control my angle of attack with the tool, not be forced onto only one less-than-optimum way. It’s like a carpenter being forced to build a room not square. Yes, it’s just as livable but you feel a bit cheated when you were given no option.

Sure, the electrons don’t care if the gap isn’t vertical, but like a non-square room, you may discover some complications later. Catching and picking track cleaning pads is a big one. In fact I’ve had a non-vertical gap catch and rip some of the rail up. Not fun!

Angled gap cuts are more difficult to control. Sometimes my eye has been off and I’ve nicked the plastic tie on the bottom of the cut, or cut an unsightly groove down into the ballast. Around frogs, I’ve had my guess of the trajectory of the angled cut be off and it’s compromised the mechanical stability of the frog wing rails.

A straight down cut is much easier to control and the path is a lot more obvious.

One definition of a craftsman is he knows how to control the tool rather than have the tool control him. For me, having the option to pick my angle of attack rather than have it forced upon me is just one more way all my motor tool usage scenarios make me the craftsman with a tool that does what I want it to do.

But if you know all this already, then yeh, it’s a Ho-Hum Moment. But then maybe YOU should write up some Ah-Hah moments, then, and share some wisdom with the rest of us! (Wink and ornery grin) 

My Aha moment

Just subscribed to running extra today, so I haven’t gotten my download link yet to see this month’s aha.  But I think you may have just given away the plot there Joe

My aha moment today was watching a TMTV backshop video (also just got tmtv today) I was experiencing a very weird sense of something out of context.  And then I made the connection.  Rick Green, host of the backshop clinic is the same Rick Green of adventures with Bill on the Red Green show!  Aha!

the slope

Here's the amount of slope we're talking about using a standard Dremel on code 100 rail. Looks like 10 or 15 degrees, once the rail is weathered it's hard to see if it is  sloped or not.....DaveB 

Joe,

Challenge accepted, Joe!

Should I follow the submissions guidelines, or would a short write-up for the "Ah-Hah Moment" column follow a somewhat different path?

Should I submit as an article idea or just write it up more as I might a forum post, and just send it to you?

The gap-

I doubt that I ever take my mandril with cutoff wheel off my motor tool,for it is so useful for many things. But that aside, The close up photo shows that burrs (hope I have the right word for the little random bits of bent metal along the cut) which really could rip apart cleaning pads- or even fingers.  Those can be cleaned up with a brass brush- even a brass brush attachment for the motor tool. Then a piece of cloth dampened in water, or alcohol or other moistening  liquid should be able to remove any particles. 

Tiny particles from using a cutoff wheel can get in to unwanted places such as locomotive gearboxes.  I don't think this is being too cautious for some years back, I was using a cut off wheel on a brass engine frame, and was wearing nearly new goggles. I did rinse them off after each use, but somehow I got something in my eye.

After the usual washing the eye with drugstore optical saline solution, I still felt something. Previously this kind of thing was gone after a night's sleep. 

But not this time. Fortunately I was able to get to see my eye doctor ( I forget his exact specialty) who put me on the microscope. He told me my eye was full of infections. I hesitated to say anything but- (I have a big mouth sometimes) I asked him to please look again as I still felt something in the eye. 

He looked through the microscope again. Then he brought his nurse over to look through the microscope. He told her to see the pink spot in the eye. That little thing? she asked. The doctor told me he had never seen such a small rust spot. He got it out and told me it was a particle of steel, and that I was lucky I hadn't come right in. The fact that it had a few hours to form the rust spot made it visible. However, I had been grinding brass. That tiny particle must have stuck to the goggles from a previous work session and lasted through thorough washing of the goggles. 

Since then I always did a thorough washing of protective goggles after using the cut off wheel.  

Victor Roseman

The close up photo shows that

   Hi Vic, Those burrs in my photo are actually the edge of the plastic filler where I filed it off a bit after the glue dried. I found an old HO scale roofwalk in my scrap box that was the same thickness as a dremel disc so I cut little pieces off it and glue them into the gasp. I let them extend down into the ballast so it helps lock them in place.  I totally agree with your warning to use eye protection when using a dremel, I've had many discs shatter over the years.....DaveB

Gaps

Just ordered them.  Wish I had them for my last gap cutting episode.  Use to use a razor saw but what the heck I had my new micro Drexel and was just dying  to use it.  Threw in the standard carborundum disk and promptly chattered my way threw the rail.  Was able to fix it with heavy body expoy putty.  No one would ever see it or notice it. But unfortunately I see it every time I look at the layout.  I know its a curse many of us compulsive modelers suffer from. So once these come in that small section of track is coming out and then nicely sectioned with these diamond dicks.

Wayne Mollohan

Providence Northern Model RailRoad Club

Cut-Off Disc

Thanks for the tip, Joe!

Definitly buy a flexible

I've used motor tools on several projects (including ones that were not related at all with model railroading) and I definitely advise anyone to buy a flexible. With a flexible, you can do quite whatever you want: drilling, sheering, polishing... much more than with the basic tool.

This is even more true if you hang your tool above the surface you work on (it can be your workbench, your layout...). You can make a versatile hanging system by using a clamp (drill a hole at the end of the clamp, opposite to the jaws, and add a hook there). You can then use both your hands when working, with more precision. The closer, the better.

The ideal system is a foot pedal switch to power the motor tool, like on a sewing machine. And since both are powered by 110/220V,

I've also noticed that the larger the disk is (whatever its structure), the faster it breaks. In any case, don't forget to wear safety glasses, but also gloves.

So I don't think it worth saving $20 by buying larger disks instead of a very versatile flexible.

Points Matter

Though what is being shown in photos is a small angle you need to remember about electricity, electrons will be more focused at points, if this point is close enough the slightly higher voltage differential will spark the gap.  This is one reason why neatness counts with electricity.

slightly higher voltage differential will spark the gap?

The dielectric strength of air is 3000V/mm. I think there is no such voltage in the MR

BRIDGE THE GAP

https://bhamrail.com/crane-rail-and-accessories/the-birmingham-rail-crane-runway-system/

Vasilis, when I saw the

Vasilis, when I saw the camel, I thought it was Wednesday !

John, I had to google about

John, I had to google about the relation between the two. Thanks, I learned something new.
I like the camel because symbolizes the patience. motivates me

can I ask

I am not trying to be an a$$ I am trying to understand if two tools are running at the same RPM, will a larger disk really run/spin faster than a smaller disk? Wouldn't a larger disk take longer to complete a full revolution at the same RPM than a smaller one? I ask because of your note (#2) on cutting rail gaps...I am just curious to learn. 

RPM vs Edge Speed

Daniel,

If the two disks are running at the same RPM (revolutions per minute) then they will take the same amount of time to complete one revolution.  However, the edge of the larger disk has farther to go in that one revolution. So it's edge speed in inches per second is faster than the smaller disk at a given RPM.

Don

RPM vs Edge Speed

Hi Daniel and all,

Don has is it correct. For a constant rpm the edge speed increases proportionally with diameter - 

If you have double the diameter, you have twice the edge speed BUT ALSO 4X the amount of energy going into the rail that you are cutting into. Kinetic energy = ¹/2 mv² - a bigger cut-off wheel also has more mass but it's the v (velocity squared) where most of the energy is that can be converted to heat when cutting with a rotary tool. This can put a lot more heat into the rail if you are not careful, causing damage to plastic ties etc.

If you are cutting at an angle and not perpendicular, then you also have a longer cut path through the rail. This also means more energy in total going into the rail as heat. The trick is in managing how quickly you put heat into the rail as well as the total amount of heat going in, so that any collateral damage is minimised. 

This is the reason that you back the revs off when cutting small stuff like our model rails with a larger diameter disc

Don Thank you...

cool beans.. thank you for the reply.. I got stumped... so an F150 with 18 inch rims going 55MPH and a Honda with 14 inch rims going 55 mph,  they are both going the same speed MPH , but same RPM as well?  

holy e = mc2

John thank you also for the reply...I think I get it..

F150 vs Honda

Daniel,

You would have to determine the aspect ratio of the tires, but assuming that the outer diameter of the F150 tires are larger than the Honda's then at the same vehicle velocity the F150 tires and wheels will turn at a lower RPM. Each vehicle engine rpm will depend on the gear ratios in both the transmission and differential (of the F150).

Or looking at it like the cutting disks. If the F150 tire diameter is larger than the Honda's, then at the same TIRE rpm the F150 will have a higher velocity down the road.

Don