Changing the speed on a bench drill

Hello all,

Firstly, I must admit that while I am an experienced musical instrument maker, my knowledge of power tools (other than my bandsaw...) is extremely limited. So please bear with me.

I recently bought a Meddings MB10 bench drill for a very cheap price, which I need for a current project (drilling tiny 0.5-1.5 holes at a high speed into hardwood), and it is perfect for that. The minimum speed is 3,000rpm.

However, in the future, I feel I will need drilling speeds of less than 3,000rpm. Ideally, I would like to have the option of going down to 1,500.

Is there a way of controlling the motor, so it can spin at half the speed? What would one need to acheive this?

All the best.

Theo

Choices are probably:

Mechanical, gives the advantage of more torque.

1. Change the pulley ratios for something that gives a slower speed. The limit would probably be how big is the biggest spindle pulley that will fit.

2. Add a extra set of pulleys into the system to increase the speeds available. Quite a complicated change.

Electrical, can be a simpler option to fit in the space available but torque can drop off as speed is lowered.

1. Fit a DC motor and use a speed control board to control the final speed. Typical of the system used on many small "hobby" lathes with variable speed.

2. Fit a 3 phase motor and use a variable frequency drive to control the final speed. The motor may have more bulk than a DC motor and so may not fit in the available space. Can be a more expensive option than the DC version.

Martin C

Might be simpler and cheaper to pick up another bench drill and avoid all the messing. They are not all that dear and you will have the best of both worlds.

Meddings did supply larger pulleys for the spindle if you needed lower speed. The other way would be to cange the motor from a 1/4hp 2 pole motor, to a similar powered 4 pole one, this would half the speed. The "only" problem there is that the current motor is inside the column, and probably a special size. Larger pulleys look as though they would be an easy option, and if need be a smaller size could be fitted to the motor shaft.

Ian S C

Hey all,

Thank you for your responses, very helpful.

Ian: Would you happen to know where one could find the lower speed pulleys these days? I have a parts list for the machine here from Meddings, and while it does list alternate spindles, they are only for a HIGHER speed, there are no spindles listed for a lower speed... But if they did exist at the time, then perhaps Meddings or somewhere else will have some spares?

Martin, would you also happen to know where one could find pulleys that would fit the MB10, that would acheive a lower speed?

Many thanks

Theo

Theo, Meddings now offer a refurbishment service for their older drills.

I'm not suggesting that you go that far, but they seem the obvious people to ask about alternative pulleys.

They even show one of your model on their refurbishment page

Regards and welcome

Bill

Theo

I have an older Medding floor standing drill and found them extremely helpful for advice and spares when contacted.

Lionel

Edit spelling

Edited By Limpet on 14/07/2018 15:29:03

I agree with Larry.

With the meddings to do any tiny, precision work, the demands on the other bench drill would not be great so a relatively inexpensive one might meet your needs.

Plus you haven't got the headroom to make use of drills/chucks of any size in the meddings.

Neil

I am not familiar with Meddings and got litte help from the web. If the machine is equipped with step pulleys the easiest method is to change the belt position. If the machine does not have step pulleys it may be driven by a universal motor: one that has brushes. If so, a router speed controller should work but torque will be limited at lower speeds. Worst case is changing the motor, either a dc motor and appropriate controller or a 3 phase induction motor and a VVVF control. As suggested by others a second larger drill has its advantages.

listen to Neil.......

have the same machine plus another, can't remember the make thats pulling 18,000rpm under the bench.....

but it not used for anything other than pilot holes, NO HEAD ROOM, like the film....hahaha.....

just get another drill press, u'll soon get fed up swoping pulleys even if it's just once or twice per year.......

go on....u know u want to......

.

I have just realised that Theo has two threads running, about his Meddings MB10

It may be worth a Moderator combining them; but meanwhile **LINK** is worth a look.

https://www.model-engineer.co.uk/forums/postings.asp?th=136707

MichaelG.

The drilling machine was supplied new with a three step pulley to give 3000 rpm, 4500 rpm, 6000 rpm. And single step pulleys for 8000 rpm, and 10,000 rpm. The optional extras were a low voltage light with an internal transformer, and a dip tray to sit the drill on. There is a bit about the machine on the Lathes UK site. I'm sure a single step pulley system could easily be made, as the spindle pulley gets bigger, make the motor one smaller and you won't need extra belts.

Ian S C