Aluminium Framed Router

[Lee Roberts]

So much for a day off only ended up working till 9pm, had to plug it in a try it when I got back, spindle fine, Z axis fine, Y axis with A slaved no problem, X axis just a rumble and rock from motor, too tired to even think about it tonight can't be too serious it didn't go bang! The two working axis have proved already it has all the speed I will ever be able to use in the flat and then some if it lived in a shed the shed would have been rocking. Would have been nice to have it all work but 4 from 5 is better than a kick up the backside.

Nm your not the only one as I've had to sit around not doing much today too :(.

Early start in the morning? Post a video of her jogging about with a big cheesy grin of joy? Go on spoil me you know you want to

Will you share with me where you got your spindle and VFD from, that is a good price maybe I was looking in the wrong place but I was seeing £300 for the 2.2's...

Lee

[lucan07]

Will you share with me where you got your spindle and VFD from, that is a good price maybe I was looking in the wrong place but I was seeing £300 for the 2.2's...
Lee

No problem Lee Fleebay had a 20% off everything offer for a few hours on 6th or 7th of April so I grabbed the VFD and spindle then, full price is £182 ans I got £36 discounted. Still has original offer ships from Germany about 5 days.
http://www.ebay.co.uk/itm/2817523492...%3AMEBIDX%3AIT

I have set up cooling in a 25ltr can of distilled\deionised water removed 10 ltr and added 5ltr of Mono Propylene Glycol to prevent any algae etc, Trying a new idea with pump though a minature 8.5w with 10ft lift seems to be ideal and totally silent.
http://www.ebay.co.uk/itm/3913989923...%3AMEBIDX%3AIT

Great thing is fits into can easily so drill three holes in cap 2x9mm for hose and 1x3mm for cable drop pump in and screw on cap sealed unit, return pipe above water and only noise is the trickle of water from the set up if you listen carefully.

Will post some video as soon as last motor sorted while tuning Y and slaved A tweaking it up, at 5m pm with 2000 accel the whole thing began to walk/run accross the room quite a weight on gantry, so I am going to have to machine either keys or flats or get some decent resin to lock timing pulleys securely, I've tapped 2 x 4mm grub screws into each pulley but would not trust them to hold at the speeds it was moving especially on round end of Ballscrew. I can't see torque or speed being a problem apart from trying to tear my hard work to pieces if I push it to hard.

Another bargain I found may be of interest was the spindle mount under £20 delivered from HongKong and it arrived in 6 days was thinking about machining a large bearing mount but at that price not worth while.
http://www.ebay.co.uk/itm/1317724808...%3AMEBIDX%3AIT

[lucan07]

Been thinking about my pulleys and how to secure them over breakfast, it may be obvious that I have little or no engineering experience so is this an acceptable way to lock pulleys securely.

My problem:
Each pulley is drilled and tapped and fitted with opposing 4mm grub screws, but motor and ballscrew shafts to which they are mounted are both round so not an ideal situation and I sure they would eventually move at some point.

My intended solution:
To drill into the pulley and shaft from the end effectively making a semi circular keyway into which I can insert a pin, I am thinking that 2-3mm drill giving 1-1.5mm semi circular key slot in both shaft and pulley would be enough to lock these connections and prevent slippage.

I know keyways tend to be slotted and have vertical sides, but as an amateur who did not consider the amounts of torque involved moving weight at speed
a) is my solution viable?
b) is 2mm or 3mm with a steel pin sufficient to do job?
c) is there a simpler way I haven't considered?

[Clive S]

Each pulley is drilled and tapped and fitted with opposing 4mm grub screws,

From my understanding the screws should be at 90' to each other also if you clip a little bit of copper wire off and flatten it then slip it down the grub screw hole it will grip the shaft better.

Loctite will also hold them on.

[Neale]

Drilling into the end, cutting both shaft and pulley, is an established technique but you will find it difficult to do accurately with an aluminium pulley as the drill will start to wander. Also, it's a mistake to drill for grub screws at opposite sides. You are now balancing the force of one grub screw against the other. Much better to drill at 90-120 deg apart, so both grub screws and the bore of the pulley grab the shaft. That might give some useful extra grip. You could just file a small flat on the shaft for one grub screw to bear against?
Good luck - I haven't reached this point on my own machine yet!

[lucan07]

Drilling into the end, cutting both shaft and pulley, is an established technique but you will find it difficult to do accurately with an aluminium pulley as the drill will start to wander. Also, it's a mistake to drill for grub screws at opposite sides. You are now balancing the force of one grub screw against the other. Much better to drill at 90-120 deg apart, so both grub screws and the bore of the pulley grab the shaft. That might give some useful extra grip. You could just file a small flat on the shaft for one grub screw to bear against?
Good luck - I haven't reached this point on my own machine yet!

The pulleys are not aluminium they are Zync plated steel quite solid so I may try a test on the end of one ballscrew I have a small drill stand that I use for holding a tapping aid that I can fix in place with Lube ands patience it should be possible without to much wandering.

[Davek0974]

Drilling in from the end is a good method, if at all possible, drill in and tap a thread - M3 or 4, then fit grubscrews, that way the pulley is secured both directions - axially and radially. You will only get away with it if both metals are similar hardness, my concern is the hardened end of the screw - if one is softer the drill will wander into it.

And yes, grubscrews at 90 or 120 degrees only, never opposite and only two screws, always file/grind a flat on the shaft for at least one screw, better still drill a little divot the same size as the tip of the screw.

[lucan07]

You will only get away with it if both metals are similar hardness, my concern is the hardened end of the screw - if one is softer the drill will wander into it.

The shafts will be harder than pulleys, I could Dremell a half round into shaft and use mill to match this on pulley would not be identical in all honesty but should be close enough to be able to run a M3 tap. Alternatively with opposing grub screws would I be better to drill through shaft completely and use a split pin

And yes opposing grub screws an amateurs mistake lesson learnt will remember that once is a mistake twice is stupid!

Decision made I had seriously under estimated how hard the ballscrew material was going to be.

Significant flat ground on one side and loc-tite to ensure grub screws stay put will be my plan of attack for now, just dremelled first one and grub screw replaced by an allan head A2 stainless machine screw should be sufficient to prevent rotation and lock pulley in both directions.