Startrite Mercury II - What does this part actually do??????

[kinsella]

Colleagues
Anyone got this machine. I picked one up recently and i can see if you turn this piece to the left it sort of locks the chuck shaft. Is that was its for or is it a brake for the shaft?
When stationary its not actually very good at locking, so I was then thinking is it a brake for the chuck??

before i test that assumption and mess something up. Who's got one or used one and knows what the part is for. See photo.

 

[Myfordman]

I've not seen/used one of those drills, but I'd expect it to be a quill lock (not a spindle lock, as I can't think of a need)

 

[flh801978]

Its a two speed epicyclic gearbox
one way is high ratio straight through
the other way is low about a 6 times reduction AFAIR

Ian

 

[flh801978]

Just to add only move when stationery and turn the chuck by hand to slip the gears into mesh
Its very usefull if you wish to drill larger holes in steels

 

[kinsella]

So it basically a gear lever. I'll take a look tomorrow and measure the speed difference. But as i've added an inverter to the 3 phase motor, its basically useless then as i can adjust the speed with the inverter?

torque an issue?

 

[Limey Lurker]

It's to hang your coat on.

 

[kinsella]

It's to hang your coat on.

Very good :lol: would be an interesting experiment

 

[blackrodd]

Am I right in thinking That must be either a 10, or 12 speed drill you have, as there are no manuals that I could find apart from the more common 5 speed.
Regards Rodders

 

[flh801978]

I'm sure the speed table behind the depth stop should show 10 ratios available

 

[woodpig]

This is the gearbox assembly.

http://www.machinespares.net/docs/342.pdf

The speeds available are on the plate at the front. Similar models are from about 95rpm up to about 3500rpm.

 

[RogerP]

So it basically a gear lever. I'll take a look tomorrow and measure the speed difference. But as i've added an inverter to the 3 phase motor, its basically useless then as i can adjust the speed with the inverter?

torque an issue?

A mechanical derived low speed will usually have much more torque than the same speed from an inverter

 

[kinsella]

So it basically a gear lever. I'll take a look tomorrow and measure the speed difference. But as i've added an inverter to the 3 phase motor, its basically useless then as i can adjust the speed with the inverter?

torque an issue?

A mechanical derived low speed will usually have much more torque than the same speed from an inverter

Chaps
I tried it today and yes it does slow down when activated. So thanks for clarifying that.

What does everyone do with the pulleys. I've put them on the fastest speed, so that i can use the inverter to control from Max down to Min. Is that the best way?

Going on the gearbox from woodpig (very helpful), that would up the torque i assume?

 

[Myfordman]

When I supply inverters for machines like drills, I programme them for operation between 10mand 100 Hz and tell the purchaser to leave the belt on "middle" speed and use the speed control. BUT when doing onerous jobs needing higher torque, to change belts first and keep the inverter at 50Hz or more. You have the luxury of back gear and can leave the belt alone and drop into back gear for the tough jobs.

For protracted periods of slow drilling the motor speed should be kept as high as possible to maintain motor cooling.