My Maker Faire Experience: 2015

It’s been a month and my voice has returned so maybe some thoughts on VMMF2015 wouldn’t be out of order.

http://makerfaire.ca/2015-vmmf-makers/

Having been to three or four editions of VMMF this was my first crack at the display side as part of the BCSME entourage. We were rather unprepared, in  fact several of us remarked in unison that we hadn’t really read the display guidelines – this while we were setting up on Friday evening… In any event we scraped through and had a fun time doing so.

BCSME’s display featured some steam locomotives, a handful of stationary engines built in one of the club’s machining courses and a variety of typical model engineering tools for public use and display. Our fearless leader (Ian) led members of the public through the various steps involved in making low melting point metal castings while Holly and James showed members of the public how to use drilling jigs and perform basic turning. Later in the weekend Bruce had a crowd watch while he worked to diagnose a jammed cross slide on the club’s EMCO Compact 5 lathe.

For my part I attempted to make N scale brake cylinders with a stereo microscope equipped lathe. Here’s one of the handful I made:

In the end I only managed to make a truck’s worth of cylinder blanks for two days work which is a decent hourly wage for sure but not really what I was aiming for. I spent the bulk of my time getting the lathe to work having spent the previous night raiding my parts collection to put the lathe together. As these things go I opted to steal a headstock/drive unit from a servo mill, and well, it didn’t mesh favourably with the metric(yikes!) tailstock’s centreline so that made drilling difficult/ impossible. By the time I had found one of my offset arbors to put that problem to  bed I was realising I ‘d forgotten to bring along the mirror crucial to reading my test indicator when it is upside down. And it just kept going like that until eventually the weekend ended. The funniest moment was after lunch on Sunday when I noticed my shadow affecting the display on  the laptop screen. Suddenly the part I was machining was visible to the general public! I assume that they had assumed that the part was just too small to render correctly. All that was needed was a 1″ piece of masking tape…

Oh well.

On the upside we had a constant stream of traffic. People seemed to be actually interested in what we were presenting in spite of our lack of preparation. Folk of all descriptions were interested in the melding of microscope to machine tool and what did what. I got a lot of questions about whether it was CNC or not which I guess goes with the maker territory, but hey, I’ll take it. locally it is the closest thing I have to a proper model meet where the people displaying stand a reasonable chance of being the originators of the work they show. GEARS is real but it is out of country, so I tried to make the best of the weekend. I must say it was really refreshing talking to folk who work locally be they engineers, artists or artisans. There was a sense of things happening, of work being done, and a recognition of relevant histories. Those sorts of things are important for me and frankly critical if I’m to maintain involvement in any public arena.

Next stop up is likely Oregon GEARS. I’ve already resolved many of the oustanding issues with the lathe and started to put together a little jig borer from the bits I have left over so hopefully parts can be made in a matter of minutes. A didactic has been drafted so that should help flush out the step by step nature of the job a bit better for those unfamiliar with the core concepts. One doesn’t want to leave the wrong impression about manual machining. Not these days.

 

I’ve included a couple of pictures below of the basic set-up I took to maker faire last month. You’ll have to ignore the micrometer thimble currently being lined and instead imagine 8 mm collets doing the work holding. As can be seen in the second image, the cross slide is a busy place! Worried onlookers need not be concerned that the microscope will fall over. In practice the stand is angled and a second clamp cinched down. For those interested, the stand is one of John Bentley’s designs and intended for the Taig lathe’s 1″ cross slide T-slot centres.  See the sidebar for John’s excellent work.

 

 

 

 

 

 

 

 

 

AH

Proto:160 form tool and holder

An exploded view of a P160 form tool with three cutting edges. The tool pictured is the female (wheel cutting) form tool.

Bo-Bo – Some experiments

Warning: Making things is dangerous. Making things with pointy edges and electric power is more dangerous still. What follows is an account of what I did and not what you should do. Safety first!

In addition to making some track laying bits and bobs I’ve been spending the fall measuring up locomotives. Slowly these measurements are being transferred into cut lists and a surprising array of miniature silversteel cutters. The motivation is pretty simple: get a locomotive together to test with. After enduring the frustration of trying to alter other people’s designs and paying for the privilege I’ve decided to try out something closer to home that does what I want it to. If it doesn’t work I can always use the Kato design with my own wheels, find a different hobby, etc.

I’m in the process of seeing whether I want to make my own drive. Effort has been put into jigs and fixtures for truck making. Here’s a couple of shots of one of the eight sideframe fixtures I’ve made up with a test piece screwed down to it. This was supposed to be representative of an LFM (1) casting with flared heels on both sides near the bottom of the journals. If you notice the   little hole  in the top left of the photo – that’s where the casting flares out on this design of LFM. The holes came about as a way of minimizing the amount of profile milling to be done. It is quicker to fret out the space between holes and then trace off around the profile fixture whatever excess remains. If you’re rolling your own it’s worth noting that there are different versions of the basic casting that ended up on Great Northern geeps and F-units. Not all castings had this feature on both sides of the journal. Some didn’t have the flare. I chose to map out this design first because the GN had a lot of them and the hole locations needed drilling in the fixture to avoid bumping and breaking the small diameter drills later on when I’m less likely to be paying attention. Sideframes without the flares don’t need holes drilling but will share the same fixture. General Steel Castings and Dofasco truck castings are different enough to warrant their own fixtures but most of what I’ve seen looking at prints through a loupe is that LFM was the primary supplier used on GN locomotives.(2)

If the sideframe looks too tall  that’s because it is – it’s .250″ brass on a .250″ fixture with a little fence to capture the work piece. The idea is that the excess will be trimmed by flipping the fixture on its side when the time comes. The cutter depth is set off of the fixture side and since all eight are the same height the journal bottoms can be trimmed in a timely manner without much thought.

The brass workpiece managed to shift while flipping it over resulting in mis-registration. I followed this up with a few bad moves on the downfeed before deciding to play around with some new cutters to see what sorts of undercuts were possible. There should either be a movable stop or a dowel to keep registration intact during the various back and frontside moves but as I’ve not settled on a place to put either item I’m making do until the part has finished its cycle.

And Bang!

The picture above shows how I screwed up the rear face of the journal area. The real cutter for this area is much deeper with rounded corners – and – currently unhardened. Because of the crash I wasn’t able to find out if I was taking too much out of the side frame so just carried on carving out the area with  the T-slotter. Oh well, next time I guess.

And here are the cutters prior to heat treatment. On the left the .013″X.125″ T-slotter and on the right the .105″ journal rear face slot drill. All backing off except for a small flat nearest the cutting edge was accomplished in an indexing block… basically a length of square bar reamed to size and equipped with a 6-32 set screw. The cutter was repositioned using  a Mark I eyeball to roughly 8 and then 30 degrees. The last little bit of backing off is accomplished after hardening and tempering with an Arkansas stone or a little bit of fine India. On the slot drill the two cutting edges were slit (off-centre) with the stroke of a fret saw. The slot drill is supposedly plunge-cutting  but I have not tested that feature on the cutter.

The more I get into it the more obvious it is that each hole is its own job. It turns out that it is quicker to load a new fixture than to change tooling and position. While spotting is mostly done in one go together with critical items like the wheel base,  as much as possible I’m setting up the fixtures to run one type of hole (pairs as the case may be) through all eight fixtures before progressing to the next hole. It’s a lot of work, but I can’t think of another way to accomplish the task that is within the range of my ability and that works.

1.)I’m told  LFM was Locomotive Finished Machinery. EDIT: Wrong, According to page 125 of Dave Hickcox’s GN Colour Guide to Freight and Passenger Equipment it stands for Locomotive Finishing Materials Co. I should probably look it up in a Locomotive Cyclopedia to be sure.   Here’s a picture of one version of LFM cast sideframe taken at Squamish, British Columbia, Canada:

2.)  GN #692 (one of the GP9s rebuilt with dynamic brakes in 1958) displays a pair of General Steel Casting trucks taken from a Cordell Newby photograph in the author’s personal collection. Although the link is to a different image, the lead truck is clearly identified by the GSC style cast in spring hanger retainer (I don’t know what else to call it) in the link below:

go to http://www.gn-npjointarchive.org/GNRHSNewby/GNRHS.Newby.Bk1img482.jpg

GN F9B #470B has a lead truck by General Steel Casting

go to http://www.gn-npjointarchive.org/GNRHSNewby/GNRHS.Newby.Bk2img184.jpg

AH