Worm/motor support metalwork: Proposed layout using 6mm angle profile.

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This is a [very] rough bit of image editing to show how the worm housing might appear from the outside. I have now used 6mm angle for the motor plate to provide a much stiffer housing. As well as being bolted to the motor plate, the motor is enclosed in angle profile aluminium for greater stability. [Belt and braces.]

Space has been left in the 6mm [1/4"] aluminium angle for the motor plug. [Shown not fully inserted here.] A chamfer on the nearest cut edge will avoid any chance of wire chafing. The cable will also be anchored with a P-clip.

The lopped off [mitered] angle and re-exposed worm and shaft is just more image editing in PhotoFiltre.

Here is the "inside" view of the worm and motor housing. The worm support angle still needs to be trimmed [notched] to make it lie flush against the motor. This step has been delayed while I ponder the consequences of the present layout. I don't want to waste the precious angle profile if I should change my mind.

Here I have edited the corner of the motor plate [angle] away. The motor plate could also be made lower to match the worm housing. Another piece of angle will be bolted to the [box] enclosing angle and then bolted down to the main 10mm thick base plate. There is no need for the box to be any wider than the worm housing profile.

It would not be difficult to reverse the entire assembly for this neater [fully boxed in] look, as seen here. Though the motor plate [angle] would need to be heavily trimmed to allow the wormwheel to reach the worm. The wormwheel housing, channel profile only just clears the wormwheel to give some idea of the clearance problems. So the closed side [shown just above] is arguably the better side to face the wormwheel. That said, the angle profile motor plate is easily stiff enough, at 6mm thick, to be cut away quite drastically near the top. I would just like to end up with a clean, professional looking job rather than an obviously amateur construction.

Stepper motor reversal of rotation direction is straightforward in the AWR Factory Menus if needed. Another downside of the fully boxed-in look is poor access to the plug on the stepper motor cable. Not a serious problem as there is another cable plug connection only a foot from the motor.

Whoops! I made a 36mm hole in the motor plate to give plenty of clearance to the hub of the larger pulley. The problem was the worm housing fixing holes slightly overlapped the large hole. Just to add insult to injury I had carefully made smooth curves on each leg of the angle profile before discovering my mistake. I shall have to make a tighter clearance hole in a new motor plate.

I'm thinking of using 10mm flat plate rather than 6mm angle profile. I may need to make a radial hole for the hex key to reach the grub screws in the pulley boss. Which is why I made the hole so large in the first place because I was using foolishly long grub screws. While in theory the angle profile provided extra stiffness to the motor plate I really didn't like the half covered - half bare appearance.

I remain unsure whether the stepper motors should be fully exposed for natural air cooling. Or use thick metal in direct contact as a more direct means of cooling by conduction and eventual radiation from a larger surface area. My plan to 'wrap' the motors tightly in angle profile [or even square tubing] might be completely the wrong approach if they should then overheat. 

Click on any image for an enlargement. 

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