X2 belt drive conversion

Gallery, Projects and General > Project Logs

<< < (8/17) > >>

raynerd:
Yes - perfect sense and thanks for your suggestion. Chris

bogstandard:
Normally when a grub screw is used and it locks against the key, it serves two purposes.

The first is to stop the key moving along and back and side to side in it's slot, thus preventing wear on either the key or the slot.

The second reason is if the slot in the pulley is not as tight as it should be, it creates a mechanical lock that prevents the pulley rotating slightly around the shaft and key. Again this is to prevent excess wear.

If you don't understand the mechanics of the reason to put it in there, it is always better to put it in anyway.

It is called 'belt and braces' or 'just in case' engineering.

John

spuddevans:

--- Quote from: bogstandard on May 26, 2009, 05:35:18 PM ---it serves two purposes. ...... to stop the key moving along and back and side to side in it's slot, thus preventing wear on either the key or the slot.
...... if the slot in the pulley is not as tight as it should be, it creates a mechanical lock that prevents the pulley rotating slightly around the shaft and key. Again this is to prevent excess wear.

--- End quote ---

Thanks John for explaining that, it makes sense now I understand that. The original spacer on the X2 is made out of steel and does not have a grub screw, I guess because it is a very tight, close fit to the spindle and key, and because of it being steel it would not wear so quickly. (and it would cost extra to have one :lol:) In the belt conversion we will be removing the original steel spacer and replacing it with our newly made large pulley made out of Ali', and hence the need for a grub screw as John said to fix firmly the key in the slot (which, let's face it, on my pulley is not quite made to the same tolerence as the original spacer's slot)

Tim

raynerd:
I see, I see

--- Quote ---which, let's face it, on my pulley is not quite made to the same tolerence as the original spacer's slot
--- End quote ---

...and that will apply to me two fold! :doh:

Chris

spuddevans:
So, After being away to london at the weekend, I managed to get back into the workshop. I left you all on the edges of your collective seats ( :lol: ) as I was part-way through making the small pulley. Well before I went away I managed to get the pulley finished, and got a start made on the base. I didnt get any pics as the camera was already packed for traveling. :( I did use my boring bar in my mill for the first time which went ok. I bored out the hole in the base for the large pulley to fit through. I stepped up from 1/4" through to 1/2" drills, and then switched to using the boring bar, I took cuts of about 1.5mm per pass (total enlargement of hole per pass - 3mm).

After boring out the main pulley hole, the 4 fixing screw holes including clearance, voila

I then cut a little off one side to bring down the width to 3.4"(ish) from the 4" original size except from a little "ear" at the back to attach one of the spacers to. I then cut off a chunk of 1" square ali bar, and then milled down a section to make it fit and give the required clearance.

And this is where it will fit

While the vice was set up and the depth was still locked in I milled a small (2mm) rebate in the other spacer block so that it too will fit properly.

I then drilled and tapped and bored clearance holes in all the right places to attach the 2 "ears", and then attached said "ears"
Bottom view:

Top view:

And that is as far as I got today. Next will be the motor mount and also drilling and tapping the top of the "ears" and then clean the whole lot up, getting rid of all my marking (and re-marking) out.

Tim

Navigation

 Message Index

Go to full version