|Project by LittleBlackDuck||posted 03-12-2017 12:25 AM||1086 views||2 times favorited||16 comments|
One of my passions is T&J model toys for which the requirements call for drilling a number of small holes, ranging from 3 to 20+ over a small circumference to simulate nuts etc… on vehicles’ rims.
While I have the luxury of a laser that makes life easier for me, my meds mush have kicked in and gone into overdrive forcing me to come up with a “manual” means of achieving this particular swiss-cheese affect in the aforementioned little bits of timber.
Starting with SketchUp, I designed a very basic jig,
cut it out on the laser, assembled it and realised I needed more medication as I was so far off the mark that my bulls eye was the size of an ants eye (??? yeh… me neither… must be the meds). So back to the drawing board and finally evolved an acceptable configuration that was buildable by even me.
I needed an indexing mechanism and came up with a spring loaded ball bearing which engaged holes laid out in an organized fashion along the circumference of a circle. After many futile attempts I finally achieved that goal.
This was then followed by the comical picture of me crawling across the breadth and width of my workshop trying to track down those little ball bearing suckers that were turned into non directional missiles by the mishandling of the compression spring whose sole purpose was to control the entire mechanism and not impersonate a lethal ballistic weapon. No sooner I found that obnoxious ball bearing, I managed to launch the spring into a non-accessible (which was always the case when I managed to observe it’s irrational trajectory) part of the workshop. Because of their small size I tried replacing the 8mm ball bearings with tennis balls but for some reason the fur on the tennis balls hindered smooth operation, so with hesitation, I surrendered that ingenious piece if inspiration. After bulk buying a heap of 8mm ball bearings and exhausting our local supplier’s supply of small springs I finally managed to assemble the unit. I wanted to super glue the spring and the ball bearing so they wouldn’t fly off, and if they did, they’d stick together, however, I managed to super glue my fingers together so I abandoned that pragmatic circumvention and proceeded to further bolstered my stock of those 2 under estimated perishables.
In the gallery pictures, I have tried to display what the jig can create and here is a link of how NOT to present a video of the jig in use, if you don’t want to beffudle your audience.
If you find you are/were going to sleep watching the video, watch the next few pictures at a more leisurely pace.
These are the components of the jig. Check out the 8mm ball bearing perched precariously on the spring.
“3, 4, 6, 8 and 24” configuration index wheel bolted into place with the “5, 10 and 20” indexer lurking in the background waiting to pounce.
Packer to straddle washer and 1/2 nut.
A well traveled “zero clearance” insert mounted.
Unfortunately I could have saved myself a heap of grief by just staying faithful to my laser and left the jig on the drawing board… (just kidding).
A novel addition to the jig was a ¼” to 8mm (or 5/16” in Yankee speak) packer/sleeve printed on my 3D printer. T&J models are designed with either a ¼” or 5/15” axle diameter that in the past required 2 different sized spindles for fabricating wheels and rims. With these little sleeves I can use ¼” bolts for both sizes. I have made various lengths of these packers to use as required.
Another feature of the jig is the cutting of the indexing wheel as a 250 toothed gear shape to simulate an easy to handle knurled knob. The wheel eventually worked even better after I sanded the teeth off because the small teeth hurt my delicate hands… (just gagging).
While the laser has made the indexing wheel a simple operation for me, a good compass, keen eye sight and a sharp drill bit will keep you amused for many a days before you seek out a laser cutting organisation to cut an accurate one for yourself.
PS. Late extra.
For anyone interested (in the concept) finding the right spring can be a nightmare. To get you started, this is a picture of the spring’s specificarion,
at least the specs on the packet may be a good starter. The spring is “countersunk’ through 2 layers of 6mm MDF… for all you non mathematicians … this is 12mm (even for large values of 6).
PPS. For those with eyesight as bad as mine, the measurements are 1/4 x 1-3/8 x .20… the spring that is… not the bag.
-- There's two ways to do things... My way or the right way.. LBD