Sunday, 3 February 2019

Cycle lamp bracket

I have created a design for a modified clamp for a Cycleafer bicycle lamp so it can fit a 35mm diameter handlebar.




I decided to do this because the handlebars on Shelley's bike have a diameter of 35mm in the centre. This is a standard but uncommon size. Normally they are between 22.2mm (7/8") and 31.8mm (1.25") but a few are as large as 35mm (1 3/8"). The trouble is, that currently, there are few full size lamps that fit the largest size. The bracket on the Cycleafer lamp does not open wide enough to fit a 35mm tube.


As usual, I have used Fusion 360 to create a model and exported the parts to STL for 3D printing.



The design uses some of the components of the original clamp, including the top plate and the lever for the M4 bolt. The latest revision can reuse the original M4x30mm bolt but it does not give much room for adjustment so an M4x35mm or M4x40mm bolt is preferable.






In addition to the M4 bolt, mentioned above, for use in the latch at one end, it needs an M5x25mm socket cap bolt and nut to secure the other end.











I have printed this using PETG with slightly thicker walls than I would normally use. The walls are 1.6mm thick, to give it a little extra strength.




The first version was usable but I have made several design changes since. I have improved the fit and sloped the front so that the original M4 bolt lever will fit, just about.




I used a couple of drops of High Viscosity Superglue (CA) to hold the M5 nut in place to avoid it dropping out while trying to fit the clamp to the bike.


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Notes:
Based on the photos in the following review, I believe this clamp will also fit the 'Berlin Standard' bike lamp:
https://www.bestadvisers.co.uk/bike-headlights

Versions:
v32 First release.
v34 Closer fitting cone and a hole for a cable tie as a an alternative, should the thin tongue break.
v42 Reuse the original M4 bolt.
v46 Minor fit changes to the cone.

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Downloads:
STL models (zip file v46)
STEP model (zip file v46)
Fusion 360 archive (zip file v46)
Licence not commercial

My designs in the Fusion 360 Gallery.
My models in the GrabCAD library.
My designs on YouMagine.com

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Saturday, 2 February 2019

Shapecut 3200 Magic Eye to CNC - Part 1

I've been interested in making my own CNC router for some time however a friend mentioned an ancient oxygen gas profile cutting machine that could do with bringing up to date.



Nothing like jumping in at the deep end. The Shapecut 3000 series machines are large industrial machines that can cut up to about 2" thick steel plate!



The machine originally used a 'Magic Eye' to follow a black line on a paper drawing.


I managed to find a video of one in operation.
https://www.youtube.com/watch?v=Vlz6i_wB_8E


These machines date from the late 1970's and apart from that video, I have found nothing else of use on the internet.



It is fairly common to convert old machines to more modern electronics. The mechanical structure is sound. There are several companies that provide this service but the trouble is, it costs thousands, often tens of thousands, for the conversion. This machine may not generate enough revenue to justify that cost. However it would make a challenging project.



I have no idea if I will be able to complete this, so I am going to put my progress in this blog to help anyone else who may attempt something similar.


Firstly I copied the ancient paper manual to a PDF, for easier reading.
The circuit diagram is, unfortunately, faded, so it is only of partial use. If anyone reading this has a more usable diagram, please send me a good quality photo of it.


So far:

  • The machine is marked as a Shapecut 3000 but I think it has been updated to a 3200, some time after 1979.
  • The motors are 400V servo motors with a gearbox. The diag says they run at 10 rpm.
  • The cost of modern servo motor drivers is expensive at over £500 each.
  • Matching modern drivers to the old servo motors would be difficult.
  • It would be lower cost to replace the motors with modern stepper motors and possibly new gearboxes.
  • Matching the new stepper with a modern driver and power supply should be easier.
  • Deciding on the required torque for the stepper might be a bit of trial and error or simply over spec the stepper and gearbox.


The CNC control part of it should be fairly straightforward. Most of the software includes the options necessary for use with a plasma or gas torch .

I like the idea of a self contained headless solution but as the gas torch has to be manually aligned on the work piece, having a large display of the tool path would be beneficial. Therefore, at the moment, I'm thinking of using Mach 4 or UCCNC running on a used PC. Either of those need some sort of motion controller card.

So few PC's have parallel (LPT) ports now that I would prefer to use an ethernet controller. These are common.

That's about as far as I have got at the moment. I'll write more when I have made some progress.

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Downloads:
Shapecut SCM 11 3200 manual (PDF)
Shapecut SCM 11 3200 circuit diagram (PNG, original A1 size)
Shapecut SCM 11 3200 frame diagram (JPeg, original A3 size)

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