Author Topic: Tales from the Wobbly Workshop  (Read 67291 times)

Kim

  • 2nd in the world
Re: Tales from the Wobbly Workshop
« Reply #275 on: August 27, 2015, 12:45:12 pm »
The ones I've encountered when people were making props and costumes out of foam, were the electric carving knife or a hot wire.  Ventilation and some skill are required for the latter, but it has the advantage that you can make weird shaped cuts easily.
To ride the Windcheetah, first, you must embrace the cantilever...

clarion

  • Tyke
Re: Tales from the Wobbly Workshop
« Reply #276 on: August 27, 2015, 02:01:10 pm »
It's mainly hot wire I've seen/used.  Pongy at times. *cough*
Getting there...

Re: Tales from the Wobbly Workshop
« Reply #277 on: August 27, 2015, 08:20:57 pm »
The ones I've encountered when people were making props and costumes out of foam, were the electric carving knife or a hot wire.  Ventilation and some skill are required for the latter, but it has the advantage that you can make weird shaped cuts easily.
Mandatory, these days, I think. Styrene fumes (and those of other insulating foams) are carcinogenic.
At college, all of the hot wire stations in the 3rd floor workshop had extraction. This was ducted and dumped, unfiltered, to mix with the traffic fumes on Southampton Row.  :facepalm:

I'm not sure how optimal a hot-wire cutter is for closed-cell foam such as Plastazote, I can see it kinda cauterising the edges in a not very nice way.
WJ's idea of 'polishing' the edges with a hot air gun is one I am not sure is necessary. Closed cell foam doesn't behave the same way as acrylic does (which does benefit from flame - or heat - polishing).
Closed cell foam edges will not deteriorate if left untreated. As materials go, it has an astonishing lifespan before it starts to fail or deteriorate. I have some closed cell foam items I made probably more than 40 years ago. They're still doing their job today.

Rohacell, on the other hand (foamed acrylic) is the king of modelling foams, and best cut (or machined) using Very Sharp (new) Tools. It is possible to cut it in slivers of 0.5mm or less without it losing structural integrity. Unsurprisingly, it is fiendishly expensive....

As I said earlier, I think I need to get out a bit more...

Re: Tales from the Wobbly Workshop
« Reply #278 on: August 27, 2015, 09:31:45 pm »
It is possible to use a hot wire cutter without generating excessive fumes. Did you know they do CNC hot wire cutters for expanded polystyrene?  :D

Polyurathane foam gives off nasty fumes if you get it hot enough to cut, though.

I have a box of Rohacell foam in the loft of my garage.  :demon:
If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #279 on: August 27, 2015, 09:39:35 pm »
I have a box of Rohacell foam in the loft of my garage.  :demon:

That is little short of being deliberately provocative  :P ;)

Re: Tales from the Wobbly Workshop
« Reply #280 on: August 27, 2015, 09:43:47 pm »
It's along side the sheets of carbon fibre/Nomex honeycomb and the roll of composite GRP/Kevlar composite sheet.   O:-)


BTW, Did I mention I used aluminium honeycomb 'Aerolam - alike' for the roof of one of my sheds.
  :demon:
If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #281 on: August 27, 2015, 10:08:41 pm »
It's along side the sheets of carbon fibre/Nomex honeycomb and the roll of composite GRP/Kevlar composite sheet.   O:-)


BTW, Did I mention I used aluminium honeycomb 'Aerolam - alike' for the roof of one of my sheds.
  :demon:

Aerolam for a shed roof?
Sweet  ;D
Over specced or what? :P

Re: Tales from the Wobbly Workshop
« Reply #282 on: August 27, 2015, 10:18:27 pm »
It was the substrate for some interactive whiteboards that were chucked in the skip when work replaced them a few years ago.  ;)
If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #283 on: August 27, 2015, 10:22:17 pm »
It was the substrate for some interactive whiteboards that were chucked in the skip when work replaced them a few years ago.  ;)
Have you asked TimO if he wants any? ;)

Re: Tales from the Wobbly Workshop
« Reply #284 on: August 27, 2015, 10:31:27 pm »
What does he need it for? It is lighter construction than the aircraft grade.
If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #285 on: August 27, 2015, 10:36:56 pm »
Spaceships!
That's his game....

Mr Larrington

  • A bit ov a lyv wyr by slof standirds
  • Custard Wallah
    • Mr Larrington's Automatic Diary
Re: Tales from the Wobbly Workshop
« Reply #286 on: August 28, 2015, 11:10:50 am »
My grate frend Mr Woolrich used to work for BA and had carte blanche to go skipweaselling for the engineers' cast-offs.  Aerolam figured strongly in his contemporary bike builds.
External Transparent Wall Inspection Operative & Mayor of Mortagne-au-Perche
Satisfying the Bloodlust of the Masses in Peacetime

Re: Tales from the Wobbly Workshop
« Reply #287 on: December 17, 2015, 09:39:39 pm »
I've just read this whole thread.  Wow! I'm envious of all the kit you've been able to use, but also all the skills you've demonstrated! :)
Is the trike based around the Atomic Zombie Warrior plans, or is the front end similarity just co-incidence?
I'm midway through building a Streetfox (with disk brakes, 20" rear wheel, jackshaft (powered in the future?) and maybe a hinge in the middle (for folding, rather than for funniness)). It currently looks like this:
2015-10-23_08-56-30 by duncancmartin, on Flickr

I love your seat - mine's plywood and foam now, but I think I'm going to have to make a shell style seat to fold it how I want to...
Cheers
Duncan

Re: Tales from the Wobbly Workshop
« Reply #288 on: December 18, 2015, 01:20:46 am »
Hi Duncan. Mine is based on the Atomic Zombie Warrior, but with a less complicated rear end - why spend so much time building from scratch when a strong set of forks will do the job?

Several years ago, before the Atomic Zombie site grew so big and he brought out his books and plans, Brad us to keep in touch and show me his projects before they were released to public view. If yoiu visit my XnTRICK Cycles website, you can see I've also buit a few of Brad's (actually his friend Troy Way's idea) Spincycles.

I've been offered a broken Trice frame, so I may be building a second trike frame based on that and then decide which works best and keeping the components on one of them.

My wooden 2X4 Lowracer has a plywood seat, but it's 2 layers of 3mm birch ply, cut across the grain and laminated up so that holds it's curved shape.

Good luck with the Streetfox build. I'm sure YACF would love to see pictures of progress on it.  :thumbsup:
If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #289 on: November 02, 2016, 02:23:42 pm »
I'm not getting enough time for projects  - babysitting grandsons and getting involved with major building works in the summer at my daughter's house.

I thought I'd share this 'work' project with you though...

The ICT teacher asked me a few weeks ago about a project for her programming group. She wanted an Arduino based machine to draw patterns in sand (like a Zen garden) by dragging a ball bearing around with a magnet. Because I have a reputation for being able to make stuff, at very little expense, I got asked. Scavenged a scanner and printer from the skip, stripped them and added a stepper motor to the printer carriage, screwed the printer carriage to the scanner carriage, bought an arduino and stepper driver chips, fitted the glass from the scanner in electrical channelling and mounted it on levelling bolts,learnt to program, and...

https://youtu.be/h0nEM4bsTwk

 :smug:



If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #290 on: December 01, 2017, 09:33:52 pm »
Bloody hell - it's nearly 13 months since I posted here!  :o

I need to sort out some new image hosting now that Botophucket has phucked-it.  >:(

I've built a new shed and potting shed over the summer, and bought an electric go-kart chassis which I re-electrified (using a 250Watt scooter motor) with my 6 year old grandson helping. An old flytipped child-car seat was added too.



https://youtu.be/Ux1gsE7lKak

It's a good job his younger brother can't reach the accelerator yet, although I think he will be a better driver eventually.

If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #291 on: December 01, 2017, 09:48:08 pm »
The latest project is the re-building of a Windcheetah 'Speedy'  (with a history, as some people have said)

This is an accident damaged recumbent trike, received from Wombat OTP.
I picked it up as a collection of bits. and there's quite a bit to do.
The company that currently owns the right to Wincheetah production seems to have collapsed, with orders unfulfilled and calls and emails going unanswered (I haven't tried to contact them, but there's a thread on the BHPC forum detailing the issue). As it seems spares will be hard to come by, I'm going to have to repair or remanufacture anything I need.

Here's the main frame before starting work:

Looking along it, it ain't quite straight - bad news.

On further examination, there appear to be no cracks to tubes or castings, and on taking measurements, the rear seems straight, but the boom is a few mm off. Not as bad as I first thought.
If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #292 on: December 01, 2017, 09:52:44 pm »
As it has been stored in a shed for some time, some parts have suffered from the damp conditions...





Lots of cleaning later, and it's nearly good enough to go. I'll do a bit more when I get to the reassembling stage



If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #293 on: December 01, 2017, 09:59:13 pm »
I stripped things like lights and cables  - even doing this means overcoming problems.

One of the gear leavers appears to have had the cable nipple soldered on in situ. Drilling a brass nipple with a hardened steel cable out of aluminium is recipe for disaster, so heat is used to melt the solder enough to release the cable...



...before drilling the rest out:

If it ain't broke, fix it 'til it is...

Kim

  • 2nd in the world
Re: Tales from the Wobbly Workshop
« Reply #294 on: December 01, 2017, 10:00:34 pm »
One of the gear leavers appears to have had the cable nipple soldered on in situ.

Why would anyone do that?   ???
To ride the Windcheetah, first, you must embrace the cantilever...

Re: Tales from the Wobbly Workshop
« Reply #295 on: December 01, 2017, 10:05:12 pm »
Some bits are just plain broke.  :-\

The joystick...






...and the seat support:



I have made a couple of jigs to hold the parts in place in preparation for repair:

If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #296 on: December 01, 2017, 10:11:21 pm »
I was very excited to see that you had posted down here  :D

I like the look of the go-cart  :thumbsup:
Quote from: Kim
^ This woman knows what she's talking about.

Re: Tales from the Wobbly Workshop
« Reply #297 on: December 01, 2017, 10:17:20 pm »
The rear wheel of a speedy is cantilevered - the hub is fixed to a spindle (Dog knows how), which fits through bearings in the frame, with a freewheel block on the other end of the spindle. The block is mounted on a lump of aluminium with a hexagonal hole in it, which fits on a hexagonal end of the spindle (held on by a locknut)...

...The hub has been damaged - lumps missing where spoke holes have been ripped through.  :-\

I need a plan to remanufacture a new hub and spindle. After a lot of thought, I have a plan that uses a disc front hub and a 15mm silver steel spindle:



With the bearings removed from the hub, I need to turn some ali spaces to fill the gap out to the spindle:







If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #298 on: December 01, 2017, 10:36:01 pm »
You might have guessed by now that I intend to use the disc mount to attach the hub to the spindle. As it is best to keep the wheel as close to the frame as possible, this attachment will be on the out-board side of the wheel instead of the bearing side.

I needed to cut a bit of 3mm steel plate to fit the disc mount, with a central hole. As I have access to a huge range of workshop machinery, the easiest way was to draw it up on a pc and laser cut the shape out of MDF - took about 10 mins!

The MDF template was drilled through onto the steel plate and the disc sawn out by hand. The centre hole was drilled to 13mm, and a shoulder turned onto the spindle to match (actually a slightly sloppy fit to aid welding penetration and get rid of any misalignment at the welding stage).

Now it's ready for welding, which I am doing with it installed in the hub to help with alignment:





No need to be neat, because I'm grinding it off, and turning it down in the lathe again:





 :D



I had intended to bore the axle out to 8mm as deep as possible to reduce weight, but the welding seems to have made the high-carbon steel axle harden at the end.  :(
If it ain't broke, fix it 'til it is...

Re: Tales from the Wobbly Workshop
« Reply #299 on: December 01, 2017, 10:46:06 pm »
That's it for now.

I need to make a jig to hold the spindle on the milling machine to cut the hexagon on the other end.

Hopefully I'll get the chance to do some work on the seat over the Christmas holiday.

I thought I had taken more photos of stages of making - once going I tend to concentrate on the job and forget to reach for the camera - sorry.
If it ain't broke, fix it 'til it is...