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

[blackburn mark]

ill do a sketch if i find time.

Why do you want such a high ratio anyway?

i want to cut holes and bearing recesses in a 50mm acetal cylinder and also engrave fine markings and im trying to avoid the complications of adding a disk brake... it feels like i might get the holding torqe i need at 50:1 (i should really do the maths)
i may well use timing belts and pullies, im not fully commited to one thing or another at the moment

with all the ice i managed to burn out my windscreen wiper motor so iv even pulled the old one apart to look at the worm gear as a possibility... thats 55:1 ratio, i think id struggle tameing the backlash on that though

[Jonathan]

avoid the complications of adding a disk brake... it feels like i might get the holding torqe i need at 50:1 (i should really do the maths)

Could stick with a worm drive and compensate for the backlash on that, either in software or use a split wormwheel sprung to eliminate backlash. If you've got 3nm holding torque then clearly that gets 150Nm at that ratio. So say maximum radius of 75mm, that gets you up to 2kN cutting force ... plenty.

iv heard this said a few times... im not sure i agree with that phil, surley the table only has to "equal and opposit" the cutting force and carry the weight of the job.... you could use blu-tac as long as it did just this :)

Yes, double sided tape is great for holding some things, especially PCBs. Effectively I would have 54mm of MDF, with some slots in it...plenty to carry the weight of the job I should think. Could try and calculate the deflection. I'm worried more about if I could do the bolts up tight enough without crushing the MDF. If I put a thin sheet of steel under the top MDF layer that should solve that.

Dad's still making legs for router - wooden frames are always his department. Going to go and help now...