4th axis brake enquiry

[Boyan Silyavski]

On the best diy heavy duty mill/lathe 4rth axis as far as i remember relation was 1:7 and there was possible via second belt change to raise that. And i remember talking to the guy and he was using 120?mm mountain bike hydraulic brakes and discs. Check ebay the standard size of brakes nowadays, could be around 200mm. Hydraulic brakes is the way to go i believe, fix the discs on the shaft somewhere.

[m_c]

On the best diy heavy duty mill/lathe 4rth axis as far as i remember relation was 1:7 and there was possible via second belt change to raise that. And i remember talking to the guy and he was using 120?mm mountain bike hydraulic brakes and discs. Check ebay the standard size of brakes nowadays, could be around 200mm. Hydraulic brakes is the way to go i believe, fix the discs on the shaft somewhere.

I'm guessing you mean the InTurn thread on MachSupport?
IIRC you could swap the belt to get a double reduction for more torque.

You can get bicycle disk brakes from 120 to 220mm, however I wouldn't use one for a brake as they're too flexy. I think the InTurn used a motorbike/scooter disk, as some of those use pretty small disks, but the disks are also pretty substantial and won't flex like a bicycle disk. He also built his own caliper setup. All you need is a lever, and a suitable taper.

[Boyan Silyavski]

Just checked my MTB and yes, if you push them from side, discs could bend but not easily, they are steel. But if mounted properly there will not be a problem. If a disk holds 100kg guy racing downhill with 60km/h, it will hold the machining too.