02-17-2010, 01:41 AM
...for repetitive jobs.
In a belated attempt to answer a question about making roofwalk grab irons, I realised that part of the answer involved constructing a jig. Jigs are useful things when you need to make a lot of the same parts - grab irons, sill steps, or roofwalk grab irons, for example. In addition t o the usual construction-type tools, good measuring tools are a must: after all, if the jig is inaccurate, so will be the parts from it.
Here are three that I use a lot: everybody should have a scale rule for their particular scale. The dial caliper is useful for making more accurate measurements and, although it's not essential, I find that I use mine a lot. The other useful measuring tool is the dividers: with them, you can easily and accurately duplicate a measurement, often a must when constructing a jig or when installing parts, such as a row of grab irons.
Here's a simple jig for making ladders:
I made mine from some hard maple which I had laying around. The stop block, at one end, is simply glued in place with carpenter's glue, with the two small darker blocks glued in place at right angles to the stop block. The smaller blocks are spacers to keep the distance between the ladder's stiles constant.
As an aside here: when using a jig to assemble parts which will be soldered together, it's usually easiest to clean the material for the parts before cutting it or loading it into the jig. For brass bars or strips, and brass wire, I find this easy to do by grasping one end of the material with pliers, then drawing it through a folded piece of fine-grit sandpaper. I usually use the wet/dry type, like the 1200 grit shown below. Reverse the material and draw it though in the opposite direction, too - this way, you don't have to keep track of which end has been cleaned.
If you don't use all of the cleaned material when doing a job, just remember that brass oxidises fairly quickly, so you'll probably need to re-clean it for that next project.
To use the ladder jig, the first step is to prepare the stiles. If they require bends at their tops, like those on a caboose ladder, make them first, then solder the two stiles together, face-to-face - make sure that they're lined-up perfectly on all edges. Next, lightly scribe a centre line up the length of the face of one of the stiles (set the dividers to 1/2 the width of the stile, then drag it along the length of the stile, using one point as a guide and the other as a scriber.
Next, set the dividers to the desired rung spacing for the ladder and "walk" it up the line along the length of the stile, making a slight impression at each rung position. Drill the holes at the marked points, then re-heat the stiles and separate them. Use files to clean off the solder from both pieces and clean out any plugged holes with the drill bit.
Below are stiles prepared for a caboose, first bent-to-shape on a form, then soldered together as outlined above, and marked and drilled. Here are the separated and cleaned pieces:
Now, load the stiles, on edge, into the jig, placing one with its bottom against the stop block (and any curved end sticking up), as demonstrated by the long strip in the photo, adding the retainer block which is clamped in place with a clothes peg. Repeat for the other stile, then use tweezers to install the rungs.
For rungs, cut them from pre-cleaned brass wire (I use .012", but this will vary depending in which scale you're working).
To obtain clean cuts, use an X-Acto blade that has outlived its original purpose of cutting wood or plastic. Simply place the wire on a hard surface (I use a sheet of temper glass, but smooth steel will work, too) and use the 'heel' of the blade to snick-off suitable lengths. Careful that they don't become airborne
and make sure to cut them longer than the width of the ladder - they'll be trimmed after assembly is complete.
When all of the rungs are in place, with their ends protruding through both stiles, apply a dab of resin flux to each joint, then solder everything together.
Removed the ladder from the jig and continue building more until you have at least enough for the job at hand.
To clean up the ladders, use a cut-off disc in your Dremel to slice off the protruding ends of the rungs and a needle file to finish the job.
Here's a different one installed on a locomotive tender:
Here's a jig for making window bars for RPOs - I used styrene simply because I didn't contemplate having to make too many of these. If you're scratchbuilding a prison, though, you might want to use hardwood, as in the ladder jig.
To use this one, groups of four wires, all bent to shallow "U"-shapes, are inserted into the vertically-oriented holes, then two longer pieces, also of a similar shape, are layed across them, with their ends inserted in the horizontal holes. After a dab of flux at each contact point, a "wet" soldering iron touched to each joint will secure the whole works together.
After removing the assembly from the jig, a cut-off disc is used to separate the individual panels and to remove the legs of the "U"s, whose only purpose was to hold the wires in place during assembly. Here are some installed in an RPO:
Here's a simple one for making brackets for hanging cooling pipes on steam locomotives:
A length of bar stock (it's easier to work from the main piece rather than to cut off shorter ones for each bracket - simply stamp-out a bunch, then cut them off) is positioned over the jig, then the open jaws of suitably-styled pliers are pushed down on either side of the first forming wire, then squeezed.
This is repeated for each required bend. To make a larger bracket for more pipes, simply re-position the last bend over the first forming wire, and carry-on.
Here's the semi-finished shape:
To use it, lay it over the pre-formed cooling pipes, and bend one end completely around one of the outer pipes, and up the back side of the assembly. I solder everything together, then use the other protruding end of the bracket, suitably bent, as a mounting post, inserted into a pre-drilled hole in the locomotive. Here are some in use:
This one is for forming steps for head-end passenger cars, but could be easily adapted to make narrower ones for freight cars. The markings denote steps for the car's ends, postal doors, and baggage doors, with the minimum lengths of material required for each part of each step: the larger dimensions are for the main body of the steps, while the shorter ones at the top are the length required for the intermediate steps.
The first bend can be formed with pliers, then the pre-bent piece is placed in the jig:
Using pliers to hold it tightly in the jig, the second bend is made. The intermediate step is formed in a similar manner - note that the formers for them are slightly narrower than those for the main steps:
This hardwood jig is used when soldering the steps together:
And here are some installed on a car:
Continued in the next post...
Wayne
In a belated attempt to answer a question about making roofwalk grab irons, I realised that part of the answer involved constructing a jig. Jigs are useful things when you need to make a lot of the same parts - grab irons, sill steps, or roofwalk grab irons, for example. In addition t o the usual construction-type tools, good measuring tools are a must: after all, if the jig is inaccurate, so will be the parts from it.
Here are three that I use a lot: everybody should have a scale rule for their particular scale. The dial caliper is useful for making more accurate measurements and, although it's not essential, I find that I use mine a lot. The other useful measuring tool is the dividers: with them, you can easily and accurately duplicate a measurement, often a must when constructing a jig or when installing parts, such as a row of grab irons.
Here's a simple jig for making ladders:
I made mine from some hard maple which I had laying around. The stop block, at one end, is simply glued in place with carpenter's glue, with the two small darker blocks glued in place at right angles to the stop block. The smaller blocks are spacers to keep the distance between the ladder's stiles constant.
As an aside here: when using a jig to assemble parts which will be soldered together, it's usually easiest to clean the material for the parts before cutting it or loading it into the jig. For brass bars or strips, and brass wire, I find this easy to do by grasping one end of the material with pliers, then drawing it through a folded piece of fine-grit sandpaper. I usually use the wet/dry type, like the 1200 grit shown below. Reverse the material and draw it though in the opposite direction, too - this way, you don't have to keep track of which end has been cleaned.
If you don't use all of the cleaned material when doing a job, just remember that brass oxidises fairly quickly, so you'll probably need to re-clean it for that next project.
To use the ladder jig, the first step is to prepare the stiles. If they require bends at their tops, like those on a caboose ladder, make them first, then solder the two stiles together, face-to-face - make sure that they're lined-up perfectly on all edges. Next, lightly scribe a centre line up the length of the face of one of the stiles (set the dividers to 1/2 the width of the stile, then drag it along the length of the stile, using one point as a guide and the other as a scriber.
Next, set the dividers to the desired rung spacing for the ladder and "walk" it up the line along the length of the stile, making a slight impression at each rung position. Drill the holes at the marked points, then re-heat the stiles and separate them. Use files to clean off the solder from both pieces and clean out any plugged holes with the drill bit.
Below are stiles prepared for a caboose, first bent-to-shape on a form, then soldered together as outlined above, and marked and drilled. Here are the separated and cleaned pieces:
Now, load the stiles, on edge, into the jig, placing one with its bottom against the stop block (and any curved end sticking up), as demonstrated by the long strip in the photo, adding the retainer block which is clamped in place with a clothes peg. Repeat for the other stile, then use tweezers to install the rungs.
For rungs, cut them from pre-cleaned brass wire (I use .012", but this will vary depending in which scale you're working).
To obtain clean cuts, use an X-Acto blade that has outlived its original purpose of cutting wood or plastic. Simply place the wire on a hard surface (I use a sheet of temper glass, but smooth steel will work, too) and use the 'heel' of the blade to snick-off suitable lengths. Careful that they don't become airborne
and make sure to cut them longer than the width of the ladder - they'll be trimmed after assembly is complete.When all of the rungs are in place, with their ends protruding through both stiles, apply a dab of resin flux to each joint, then solder everything together.
Removed the ladder from the jig and continue building more until you have at least enough for the job at hand.
To clean up the ladders, use a cut-off disc in your Dremel to slice off the protruding ends of the rungs and a needle file to finish the job.
Here's a different one installed on a locomotive tender:
Here's a jig for making window bars for RPOs - I used styrene simply because I didn't contemplate having to make too many of these. If you're scratchbuilding a prison, though, you might want to use hardwood, as in the ladder jig.
To use this one, groups of four wires, all bent to shallow "U"-shapes, are inserted into the vertically-oriented holes, then two longer pieces, also of a similar shape, are layed across them, with their ends inserted in the horizontal holes. After a dab of flux at each contact point, a "wet" soldering iron touched to each joint will secure the whole works together.
After removing the assembly from the jig, a cut-off disc is used to separate the individual panels and to remove the legs of the "U"s, whose only purpose was to hold the wires in place during assembly. Here are some installed in an RPO:
Here's a simple one for making brackets for hanging cooling pipes on steam locomotives:
A length of bar stock (it's easier to work from the main piece rather than to cut off shorter ones for each bracket - simply stamp-out a bunch, then cut them off) is positioned over the jig, then the open jaws of suitably-styled pliers are pushed down on either side of the first forming wire, then squeezed.
This is repeated for each required bend. To make a larger bracket for more pipes, simply re-position the last bend over the first forming wire, and carry-on.
Here's the semi-finished shape:
To use it, lay it over the pre-formed cooling pipes, and bend one end completely around one of the outer pipes, and up the back side of the assembly. I solder everything together, then use the other protruding end of the bracket, suitably bent, as a mounting post, inserted into a pre-drilled hole in the locomotive. Here are some in use:
This one is for forming steps for head-end passenger cars, but could be easily adapted to make narrower ones for freight cars. The markings denote steps for the car's ends, postal doors, and baggage doors, with the minimum lengths of material required for each part of each step: the larger dimensions are for the main body of the steps, while the shorter ones at the top are the length required for the intermediate steps.
The first bend can be formed with pliers, then the pre-bent piece is placed in the jig:
Using pliers to hold it tightly in the jig, the second bend is made. The intermediate step is formed in a similar manner - note that the formers for them are slightly narrower than those for the main steps:
This hardwood jig is used when soldering the steps together:
And here are some installed on a car:
Continued in the next post...
Wayne