Friday, 21 March 2008

All the bits put together

Finally the fully completed article all put together.

This will be the last post covering construction of the Ball Mill other than if it sneaks into shot as I work on other things.

Making Milling Containers

The Milling container made out of 4" (110mm) Pipe and End Caps. Again I purchased these from Hunts Pipeline Supplies in Normanton, West Yorkshire they are really helpful and can supply pipe cut to length.

The pipe and the end caps are very robust and should with stand using larger and heavier balls if I need to.

One of the End Caps is glued on using a solvent adhesive and the other just slides on.

These are just fine for powders but if I need to mix/grind using liquids of some variety or other I will need to use a liquid tight inner container.

Saturday, 15 March 2008

Milling with Balls and a Kitchenaid

OK here is the completed ball mill, all the separate parts put together and milling.

In the container on the mill are 50 10mm steel ball bearings and the lumps of anhydrous magnesium sulphate that need to be ground to a fine-ish powder.

The elastic bands round the container are to reduce slippage and help the drive roller with traction.

I will complete the milling during the week when the noise won't disrupt as many people, it being the weekend and all.

Fitting the Adapter to the Mixer

Here is the adapter inserted into the Kitchenaid food mixer's PTO.

All ready to go.

PTO Adapter Assembled

Here is the assembled Kitchenaid PTO adapter with the flexible coupling attached.

Note the bearing retaining pin inserted and bent over to stop it dropping back out.

Kitchenaid PTO Components complete

The components for the Kitchenaid PTO adapter complete and laid out.

The turned and filed 12mm Aluminum Bar, turned down to 8mm (Bearing race inner diameter and inner diameter of the flexible coupling) and drilled to take a wire pin. The pin is to stop the bearing from moving down the shaft during use.

Note the piece of copper wire to use as the bearing retaining pin and the Skate bearing.

The purpose of the bearing is to keep the PTO shaft roughly aligned with the center of the housing even when the alignment is displaced. I guess it stops things catching and rubbing.

Thursday, 13 March 2008

Finalised Xilinx Development Environment

Having spent the last 4 or 5 days messing with setting up a build environment for the up coming Servo Controller design work I have finally got a method that seems to do what I want even though it appears to have a few installation glitches.

Most of my development environments are stand alone machines set up as Virtual Machines On a Ubuntu Workstation running VMware-Server. This makes it easier to backup/restore and ensures that one set of build tools and their upgrades has no effect on another.

The final model that seems to work (at least until I try and use it in anger) is Ubuntu Feisty (7.04) with the down loadable Xilinx netpack 9.2i installed as the development environment.

I needed to get the single file complete down load from xilinx even though it is huge. Installation proceeds relatively painlessly initially but does not give you the opportunity to enter a product code. As the installation progresses there appear to be 5 zip archive which won't uncompress these fail with errors and when complete xilinx's update utility fails part way through too.

When you run up the software though it looks to be a runner.

We'll just have to wait and see.

Turning a PTO on a Drill Press

The Ball Mill frame is now glued and screwed together and awaiting some milling. Last bit to make is the PTO (Power Take Off) adapter.

Our food mixer has a PTO on the end of the body that is used to plug other accessories into. This PTO is recessed and is simply a 12mm square key in the end of a rotating shaft.

I have some 12mm square aluminum bar and have cut out a section to make the adapter from.

The rubber hose of the flexible coupling already made for the purpose though needs to be fitted to a round 8mm shaft.

Here's a picture of the drill press being used as a rough lathe.

Basically the Aluminum bar to be turned down is clamped in the Drill Chuck and left hand offset lathe tool is clamped in the Drill Press Vice. If it is all carefully aligned then the piece can be turned in stages by running the drill and pressing the rotating Aluminum bar towards the Lathe Tool.

It is problematic to take too much material of at a go as the arrangement is a touch prone to vibration which messes up the alignment.

The results are a touch rough but look to be serviceable. Lubricating the workpiece with 3 in 1 oil at regular intervals seems to improve the cutting speed and reduces vibration.

Hopefully this will get finished over the weekend.

Monday, 10 March 2008

Ball Mill Frame Ready for Screwing

The Ball Mill Frame put together with the rollers (They just slot easily in to the bearings inner races) and ready for Gluing and Screwing.

Note the end of the drive roller sticking through the end block. This is where I will be attaching the flexible drive coupling we made earlier.

The rollers are spaced 90mm apart in anticipation of using inexpensive 110mm plastic soil pipe and fittings to make up milling containers.

The end support blocks which also act as spacers for the frame sides are 140mm long to ensure that we get adequate clearance for the 110mm pipe and fittings.

Frame and Rollers Laid Out

The Rollers and Frame components laid out. Note the bearings have been pressed into the end support blocks.

I used a socket from my socket set (with the same Outer Diameter as the outer race of the bearings) as a drift and a vice as a press to push the bearings into the 22mm holes in the wood blocks. It is quite a tight fit.

Take care no to push them too far in as the inner race will foul the bottom of the hole. (The 22mm Holes don't go all the way through)

After drilling the 22mm holes with the hole saw I drilled 10mm holes right through each 22mm Hole center to ensure that the 8mm drive shafts do not catch on the wood.

Drill Press Setup

Here's my repaired drill press set up ready to drill the holes in the end support blocks for the bearings.

Note the line drawn around the end of the 22mm hole saw to gauge the depth of the hole and make all four the same.

22mm is just the right size for the outer race on Skate Bearings, it makes the fitting tight enough to hold the bearing in place without needing any other form of fixing.

Monday, 3 March 2008

Rollers and Coupling Complete

Here's the end detail on the Idler and Drive Rollers showing the bearings slipped on to the ends.

Here's the Idler Roller, Drive Roller and Flexible Coupling complete.

The Idling Roller Assembled

Here is the Idler Roller construction finished. Note the Skate Bearings slipped on to the ends of the roller. These will be held in place by the mounting blocks I have yet to make.

Sticking the Rubber to the Rod

Here I started to assemble the rollers. As the 8mm tube was a loose fit I smeared a quarter of the rod with Evo Stick. I did this half the way down so that as the Rubber tube is slipped onto the rod (Using a twisting action) all of the Evo Stick is smeared inside the tube with non left to clean up by the time the rubber tube has made it to the end washer.

The Evo Stick helped slide the rubber onto the rod but when it has set will stop the rubber from turning on the rod.

Does all of this sound dodgy or do I need to get out more.

Ball Mill Roller Parts

OK Here are all the parts for the Ball Mill rollers laid out:-

2 pieces of rubber tube 8mm inside diameter at 300mm
1 piece M8 threaded rod 333mm long
1 Piece M8 threaded rod 336mm long
4 608 Abec 7 Skate Bearings
4 Nyloc M8 nuts
4 M8 Washers
1 short piece of rubber tube 8mm inside diameter to use as a flexible coupling
2 Jubilee hose clips to attache the flexible coupling

Umm the red stuff in the background is my kitchen table. It is after all kitchen table technology.

Rubber Tube for Ball Mill Rollers arives

The Rubber tube I had ordered from Machine Mart arrived today. This is to make the sticky part of the rollers for my Ball Mill. I ordered two sorts because I wasn't sure which would work best.

Their Gas Test tube is the right diameter for a tight fit on M6 Threaded Rod.

Their 8mm Air Line tube is a loose fit on M8 Threaded Rod. Unfortunately the smallest quantity of this I could Get was 10M but i have a feeling I will be using the surplus elsewhere.

The Air Line tube arrived with crimp fitted unions on each end. As it was a shame to waste them I cut them off with 60cm tails so that I could later add PCL hose fittings to them and use them as Air Tool quick release tails.