Metrology Monday: Height Gauge

The first measuring tool I want to cover is the one depicted in my teaser photo, the height gauge. I expect that things will get a bit more consistently structured as I progress in this series but I aim to cover what the tool is for, features and what the options are and any alternatives.

What Is A Height Gauge For?

This may surprise everyone but the basic use of a height gauge is used to measure height. More specifically, the height of a point above the surface the gauge is sitting on, ideally a flat surface. (Next week, surface plates!) The gauge has some sort of linear scale and a probe. You move the probe to the point to be measured and take a reading. This is also probably the least useful use of a height gauge.

The pointy probe is called a scriber and, again those machinists with their tricky obscure names, can be used for scribing a line at a specific height. This seems to me to the most useful function. My gauge’s scriber has a sharp silicon carbide tip so I imagine it can put a scratch in any material I am planning to work with. I have visions of getting all the handrails at the same height or marking cut lines for kit bashing.

The third use of a height gauge is as a stand for a dial test indicator to use for checking the parallelism of a surface with the surface the gauge is sitting on or the flatness of that surface. This is more of a machinist thing where you are attempting to judge how reliably parallel machined surfaces are as reference points. I suppose you could check wheelsets for concentricity.

Lastly, the dial test indicator/gauge combination can be used to check multiple parts for conformance to a specific height. You set it up to a standard and then pass multiple instances of a part under the indicator probe to see how far out they are from the standard.


My height gauge is a Mitutoyo 18″ Vernier Height Gauge. It is graduated in both imperial and metric and reads down to .001″ and .01mm respectively. It is a good quality model but way taller than I am likely to need but was available used for an excellent price. If I was buying one new, I would get a 12″ or even a 6″ one. I don’t inticipate the need to mark a lot of truncation lines on O scale rolling stock.

Like almost any took, height gauges are available in a range of qualities from plastic maybe junk up to ludicrously accurate and breathtakingly expensive models. In fact, machinists usually talk about toolroom versus inspection grades in terms of metrology tools. Inspection grade is for when they start talking millionths of an inch and not what I need.

In addition to Vernier models, you can buy gauges in dial and digital models with escalating price levels for each type. Digital models are handy in that you can zero the display at any point. My model can be zeroed only at base surface level or thereabouts.


The common economical alternative to a height gauge is a surface gauge. It is more or less the scriber on a stand without the measuring capability. Presumably you can also hang an indicator off of it as well. You can buy surface gauges but shop made ones are a common beginner project.

Next week I plan to cover the surface you set you gauge on.

Woodwork Complete

Yesterday, I finished assembling the frames for the backdrop and light bar for Comstock Road. Other than whatever accessory mounting work might come along, that concludes all the actual cutting of wood with only the gluing of hardboard panels and installing mounting hardware left to make things actually useful.IMG_20200523_135222617

I came up with a better temporary assembly jig by putting the framing square on the outside. This allows me to just bang both pieces into the corner and clamp; much more efficient than having to separately align the ends with the square on the inside.

Hopefully, I can get the panels glued on over the next day or so and start getting things mounted. If all goes according to plan, Comstock Road should look dramatically more complete in just a short time. Of course, some actual scenery wouldn’t go amiss, either…

Modelling in the Time of Covid-19

Like much of the world, Ontario, Canada has gone all-in on social distancing as a mitigation to the spread of the Covid-19 virus. My household has been avoiding non-essential interactions as one should. Humourous declarations aside, socializing with other model railroaders is non-essential which is not the same as un-missed. Humans are a social species and, despite some opinions, that includes modellers.

As an experiment in a face-to-face get together at the pub, I invited a few model railroad friends to join me last night for a video based meeting “at the bench”. Five us got together using the Zoom conferencing app to spend part of our evening chatting about the usual things, current projects, tools and tips, our choice of beverage, and the like. Bernard Hellen even worked in a video tour of his Quebec Gatineau layout.

I consider the night a great success especially when my goals were on the order of let’s give it a go. The Zoom app worked well for us but there are numerous other video and/or audio meeting options out there. What we lacked in pub atmosphere we gained in lack of travel time and proximity to our actual hobby sites.

I encourage others to consider setting up their own virtual meets. Even in the eventual absence of a pandemic lock-down, it looks to be a nice way to increase one’s social participation in the hobby or whatever shared interests you care to hang the even on.

Book Nook Mockup

It appears that I have some time on my hands in the next few weeks so I intend have a go at my proposed railway themed shelf insert. I cut the pieces for a 8.5x11x6″ wide box from 1/4″ plywood on my new table saw(more on that later). In my enthusiasm, I glued one side to the back before I realized that one would generally find it easier to build up the scene before enclosing it inside a box…

So, last night I took some salvaged foamcore and mocked up an alley. The black colour makes the jog in to the right hard to pick out but, like a bare plywood baseboard, I can see the intended result in my head. The major point was to check lines of sight which were satisfactory.

Next step is permanently glueing the foamcore together (currently held with straight pins) and attaching each section to the appropriate wall. I haven’t committed to scale and gauge yet but, as the bit of N scale flex indicates, On18 is a possibility. This would put me in the neighbourhood of the Guinness brewery railway’s 22″.


Turnout Control Progress

I have mentioned previously that getting hand laid points connected up and suitably under control has been a stumbling block in past efforts. The achievable scope of Comstock Road (4 or 5 turnouts total) makes the mental size of the task easier to contemplate. I have begun the new year as I mean to go on, by tackling the mentally hard things and have made further progress.

First up is the connecting rod from switch stand location to throw bar. Increasingly prototypical possibilities have occupied my imagination but when I found myself contemplating scratchbuilding scale clevis’, I realized that I was making things harder than they should be, certainly for a first attempt. I resolved to make something out of the piano wire on hand.

I needed an eye or loop in the wire to connect to the vertical shaft comping up from beneath the layout. (I am going for a rotational motion like a switch stand rather than the model railroady back and forth in a big hole. I fashioned a simple jig consisting of a piece of scrap plywood with a nail driven in and cut off, and adjacent to a piano wire sized hole. A right angle bend near the end of the wire goes into the hole and the wire is wrapped around the nail to form the eye. I got the idea for this jig from the Animated Scale Models Handbook.

Here is the jig.bentwirejig

And here is the result trimmed up.eyeinwire

I have got the vertical brass tube and wire combo installed and connected to the throwbar. (We pause while I dash downstairs to take a photo of the installation which I apparently forgot to do. Lack of photos is usually a good sign since it indicates that I have got a head of steam up.) Here is a shot of the connecting rod installation. Bending the crank in the end of the vertical wire was a challenge and I will consider better alternatives such as soldering on a separate piece of brass bar. It does work and will be concealed by the switch stand. The other reason for a separate bar would be to allow the vertical wire to continue up through the stand so the target can rotate.connectingrod.jpg

Finally, we get to installing the servo, Tam Valley Octopus servo driver and associated electrical bits. I have got as far as fashioning a bracket for the servo using a section of 1/2″ aluminum channel from the big box store. I picked this idea up somewhere in the model railway reaches of the internet and it works a treat. The servo is just a friction fit in the channel after a slight pinch with a pair of pliers.bracketmk1

Micromark Spiking Pliers

After a very stressful couple of weeks, it was good to get home and do a bit of work on the layout. I finished correcting the various gauge tightness issues on the high track turnout (rail braces can only push in, not pull out so you had better start wide) and have got the guard rails and rail braces installed. I will still need to fit the gauge plates and throw rods but the test car runs through each leg if I spike the points over. I am pleased that I have got things all working without messing up the flowing lines in the original Templot template.hightrackturnout

In doing this bit of trackwork, I have been trying out another one of my purchases from the GTA Train Show: a pair of Micromark spike insertion pliers. I had been meaning to get a pair whenever but a vendor at the show had a large array of Micromark items available including the pliers so I jumped at the chance to get them right now.

The plier are similar in feel to rail nippers but have flat jaws with a T-shaped groove in the ends to hold a spike. My dodgy photo show the T but the Micromark site has a much better version.


These pliers are kind of pricey and I was not certain they would work with the Proto87 Stores etched spikes but it turns out they do! The fit isn’t tight but it works well enough and considerably better than the ol’ needle nose.

I estimate that using these pliers doubles the speed at which I can get a spike in while also reducing the number of bent spike failures. Bent spikes are an expense in modeler composure if nothing else. 10 seconds vs about 20 doesn’t sound like a big deal and in the single case it isn’t. If I calculate the total savings in time then the purchase is a no brainer.

roughly 36 feet of track x 22 ties per foot x 4 spikes per tie x 10 seconds = 3160 seconds ~ 9 hours

~$30 / 9 hours is 3.33 / hour.  Anyone’s time is definitely worth more than that. The reduced aggravation from more precise spike placement and fewer (almost none) bent spikes also significantly increases my enjoyment of track laying. Another on my list of should have done it a long time ago things.

First Turnout Done-ish

I have been remiss in posting but I am pleased to report that some of that time away was spent actually working on Comstock Road which is the primary point of this exercise. I have got all the rails and most of the details installed or at least fitted and awaiting installation on the first turnout. I also got about a foot and a half of the diverging route laid beyond the frog. Therapeutic pushing of the test car back and forth now includes the sweet sound of metal wheels running through the frog.

I still need to install the gauge plates and throw bar but I did get as far as getting them cut to the correct length. These cast brass Right O Way parts need to be cut to length, at least for Proto:48 gauge. I made a start on a jig for sizing these so I can repeat without having to measure each installation. It is the minimalist approach of some lines on a block of wood. I do the actual cutting with my bench pin and saw frame. I am pleased to have gotten enough practice with these tools that they now feel like the easy solution not merely the necessary one.

Here is an overall shot of the turnout. I think I will need multiple closeups for a useful tour of the detail parts I used.oneanddoneish.jpg


My first attempt at cutting a rail gap on Comstock Road with a motor tool cutting disk did not produce satisfactory results. Maybe I am just picky but this looks terrible.


Not the effect I am going for with the baseboard joints. To remedy this, I unsoldered the left side, filed the ends square and resoldered the rail closer. This looks like it will do.


I will have to figure out what to do in general. I can’t use my jeweller’s saw since I can’t get the blade down horizontally that close to a surface and the underside at the joints is encumbered with support structure so no drilling a hole and slipping the blade through.

Best option I have so far is to butt separate pieces up at the joints. It makes alignment a bit of an issue but it is more or less how I do it for regular joints anyway. Joint bars are applied afterwards merely for cosmetic effect.

The sharp eyed viewer may notice that the plastic tie plate on the left has melted during the resoldering operation. Not entirely unexpected but I was relying on those spikes to maintain alignment. It will be scraped out and replaced. It also serves as a caution about in which order soldering and tie plate installation need to happen.

Weekend Reading: Making Rural Buildings for Model Railways by David Wright


Curiosity inspired by the cursory mention  of modelling stonework using Das clay and PVA over cardstock drove me to seek further information. Not coincidentally at all, David Wright has authored more books in addition to Modelling Branchlines. I was please to discover that his works are available via e-book from the usual North American sources. I chose Making Rural Buildings for Model Railways and dived right in.

I have not finished reading but I have read more than enough to be pleased with my purchase. The book includes a substantial chapter on the various materials and details found in rural buildings in the UK: wattle and daub, stone, brick, wood, slate, tile, thatch, and so on. While not directly applicable to any of my (current) modelling projects, I found it entertaining nonetheless and I imagine anyone else interested enough to buy this book will too.

After the prototype information, Wright dives into listing various techniques for modelling structures built of the various materials. Instructions are generally detailed enough to make me believe I can do it. I will probably never need to model a thatched roof but I think I could.

There are at two or three ideas that I want to try soon and will probably test them out on my shed:

  1. PVA and Das on foamcore to produce a stone foundation for the shed.
  2. Double-sided tape with peel-off backing applied to cardstock and then cut out for details such as window sashes and in my case, door hardware. One can produce custom peel and stick items. And soon discover why people pay the laser cutting guys to do it for them. 🙂
  3. A technique to create a sagging ridge line on a roof by cutting a bit out of the fold in the sub-rood and rejoining with tape. My shed is heavily weathered and should reasonably have an imperfect roof.

There are several other things on my list to try once I come up with a reason. I am certain more will join the list as I finish this great book.

Making Rural Buildings for Model Railways is available both in paper and electronic forms and to the publisher’s credit, the e-book price is substantially less than the paper version. There is a companion volume, Making Urban Buildings for Model Railways as well as Modelling Ports & Inland Waterways. I will almost certainly acquire all three.

Pins In: Small Progress Is Still Progress

In his wonderful books, Iain Rice talks about being set up so that even 10 or 15 minutes of time can be used to advance something hobby related even if it is merely ballasting a foot of track.  The concept that small amounts of regular progress add up over time is something that is intellectually easy to grasp but not necessarily emotionally so.

The last week has been seemed sparse on moments of spare time coinciding with motivation.  Remembering Iain’s words, I did manage to make a few advances: acquire a poplar 1×3 to embed the section alignment pins in, cut that poplar into blocks, glue the blocks in and, tonight, install the pins in the first pair of ends.

I am using Lee Valley table leaf alignment pins.  (I am fortunate to be able to claim Lee Valley Tools as a local source which may be cheating a bit)  Some of the barrier to progress was the nagging worry that I would duff the pin install and right off some ends.  Of course, avoiding mistakes by not doing anything is not a better solution so, onward.

Despite my trepidation, the first result is acceptable.  Bang on for horizontal and only barely perceptibly off vertically.  Which is the opposite of the expected failure axis since vertical was against a fence.  The fit itself is tight enough that there is no perceptible play which is what we want.  Phew.

alignmentpins Second set of pins are waiting on some glue to dry since somebody, ahem, tried to plane down a slightly proud block end which resulted in what you should expect across the grain: splitting an edge.  Glue and clamp currently remediating that learning experience.