AeroModeller – June 2018

41

would be a bonus. After some research

I established that for my intended use a

lead screw, as opposed to a belt drive

system, was the one to go for, and

came across the Ooznest C-Beam after

browsing the good old Interweb.

The C Beam is one of many

OpenBuilds designs by Mark Carew.

OpenBuilds has grown into a community

of enthusiasts that base their designs on

the V slot system of components Mark

distributes world wide; components

in the UK are resold by Ooznest http://www.

ooznest.co.uk/C-Beam Designs are

shared so they can be copied, modifi ed

and repurposed by other enthusiasts.

After speaking with Ryan at Ooznest, I

was in no doubt that this guy knew his

stuff and gave totally impartial advice.

Another reason I decided on the C Beam

was there is a superb build video on

YouTube. It was like having a personal

tutor guiding me through every step. You

would have to try very hard to not get

it right.

A Kit of Two Parts

There is no denying you will be faced

with a lot of parts and I mean a lot but

don’t get fazed. Everything is bagged

and clearly marked and then all the

relevant bags grouped together and

boxed to enable each specifi c item

to be built i.e. X, Y, Z actuators, the

chassis and the electronics. A number

of tasks are replicated so once you have

made say one V slot guide wheel which

comprises of two bearings, one shim and

the outer tyre you repeat this another

thirteen times; the pile of bits will quickly

shrink. The actuators, although diff ering

in length, are identical in how they are

made, so once you have fi gured out

one the next two are easy. One mod in

the latest kits is the slight under sizing

of the ACME lead screws; this came

around to make the assembly easier.

To compensate for the modifi ed lead

screw a new nut block was designed

to take up any back lash in the system,

however the new lead screw is now a

little loose in the bearings and lock collar.

According to the instructions you don’t

need to do anything as it won’t aff ect

the performance or accuracy but could

produce a little noise, so I decided to slip

over a short length of heat shrink tubing;

this proved to give a perfect fi t on the

bearing. I also did the same thing at the

other end of the lead screw where the

Custom V Channel aluminium extrusion is used

to construct the chassis and gantry.

Using T-Nuts and these sturdy angle brackets the

components are securely fi xed together.

These angle plates ensure the rigidity and

accuracy of the chassis.

For this version of

the C-Beam, three

linear ACME lead

screw actuators

need building.

A recent re-design of the ACME leadscrew

to enable easier assembly dictates you need

to add a thin sleeve where the ball race

locates. I used heat shrink tubing.

This carriage plate assembly is

for the X and Z axes. It’s where

the router ultimately mounts. The

new modifi ed nut block takes out

any backlash in the system.

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