1.7*0.74*0.4m Mill / Router building...

[blackburn mark]

What feedrates do you/other people normally use with MDF?

cant help you there, im not into wood... im just going off what iv seen on the net

My problem with the X motors is one of the nuts is stiffer than the other, and the screws are a bit bent. I put them under tension to remove the bend, however that doesn't help when the gantry gets to the end of the bed since there's no give in it and as a result it often stalls

im assuming you slackened everything off at one end (nut housing and bearing housing) and ran the gantry to that end and nipped it up, then did the same at the outher end... back and forth a couple of times to make sure

i read somewhere that i might need to staighten my screws when they arrived, mine are only 750mm so i got away with it
i was thinking i would need a reasonably flat surface to find the curve and use my knee to ease it out
as long as its a nice lazy curve you should be able to get the worst of it out...... bit more of a problem if its a short bend, it would be pretty easy to make it worse

Hmm, I thought 3600mm/min was tedious

Z still works at 10000

your definitely 18 :)

[Jonathan]

im assuming you slackened everything off at one end (nut housing and bearing housing) and ran the gantry to that end and nipped it up, then did the same at the outher end... back and forth a couple of times to make sure

Yes I did exactly that. I think I'll try it again.

I saw on you-tube a video about making ballscrews and they straightened it by putting the screw between two blocks, and pushing down in the middle with a lever to bend it.

[blackburn mark]

I saw on you-tube a video about making ballscrews and they straightened it by putting the screw between two blocks, and pushing down in the middle with a lever to bend it.

sounds like a winner
just take your time untill you know how much pressure it takes to get it to move or youll end up going passed the sweet spot and youll be chasing muliple curves up and down it till new year :)

[Jonathan]

I relieved most of the tension on the X screws and now it's much better. Seems happy at 3600mm/min over the whole bed. I'm using a 42T pulley on motor, and the 28T pulley I posted about earlier on the 2.5mm pitch screw.

Bed surfacing, not terribly exciting but it demonstrates the vacuum working reasonably well:

http://www.youtube.com/watch?v=Jb1TL..._order&list=UL

[Jonathan]

Been doing a bit more testing, latest videos:

This is the video of the first ever test...
http://www.youtube.com/watch?v=ZrhZL..._order&list=UL

And here I tried machining some aluminum:

http://www.youtube.com/watch?v=b4NrS..._order&list=UL

Bit of a faliure! I think I'll try that again but with it mounted higher on the bed. I could see/hear the Z wobbling.

[blackburn mark]

Owch !!!
a bit uggly on the aluminium :( im a bit gutted
i was over the moon with mine, 3mm single flute 3000rpm, cant remember the feed i also had a go with the engaving spindle at about 10000rpm cutting small fonts (low feed) and they both were lovely and crisp

if mounting the work higher doesnt work out to well id be really tempted to stick a block n tackle above your gantry and make provisions to drop it down by 3/4 for alli and any fine work

im confident you would be amazed at the diffrence it would make
i guess it depends on what you are going to do with the machine generally

[Jonathan]

Owch !!!
a bit uggly on the aluminium :( im a bit gutted
i was over the moon with mine, 3mm single flute 3000rpm, cant remember the feed i also had a go with the engaving spindle at about 10000rpm cutting small fonts (low feed) and they both were lovely and crisp

That's a lot less aggressive than 3 flute 8mm ballnose with 1mm DOC and 2m/min I tried! Anyway I've since noticed the plywood router mount I made isn't as tight as I thought which should make a huge difference.

I think I will look into making it easy to lower the gantry.

Having said that it's working nicely with woods:
(Wind turbine blade mould section)
http://www.youtube.com/watch?v=93SSlH0ldC4

We got chickens recently, so I made an egg holding device for my Mum for Christmas, hopefully it will go down well:

http://www.youtube.com/watch?v=GZC_0PWQc3g

I'm certainly pleased with the finish on that.