Mini-lathe dying..?

Ron,

1k and 10K are the most commonly used pots so their prices are good - there are no inexpensive 4.7kOhm pots with switch in a conductive plastic or cemet that I could find ( found some in Hi-Rel products - over 80 Pounds ea..)

You could comfortably use a 5k pot though - Bourns 86R2A-R16-A13/R51L, but pricey - $25.00

A neat trick - use the 56AAD part and at the same time buy a 10k 1/2 watt carbon resistor, and place it in parallel with the pot, ie, connect to the pot outer terminals - the lathe electronics won't know the difference.

The 10k pot may well work with your lathe, but adding the 10 cent resistor makes that you don't have to think about it.

You could just buy the maker's replacement pot, but with the 56AAD part, at least it should last the lathe's life.

Joe

Thanks Joe I will give that idea some thought, the suppliers pot is over £10 so its not as though it is cheap especially when you consider there could be a question mark over its quality.

Ron

I wouldn't replace it until it actually fails.

A squirt of switch cleaner is unlikely to void your warranty but replacing the pot might. Plus it's quite likely the dirt that caused the problem is now dealt with.

Neil

Hi Neil, you are right I dont plan on changing it unless it actually plays up again.

Ron

p.s. with a bit of luck it may now go on for years with no problems.

Edited By Ron Laden on 17/11/2018 16:27:32

One of the first mods that I did to my mini-lathe was to make a cover for the hole in the control box by punching a hole into the lid of a 35mm film container, waxed the leadscrew, removed the saddle and tail bearing, slid the device along the leadscrew then filled the cap with neutral cure silicon rubber before pressing it into place against the control box.

This was over ten years ago and it's still functioning quite well. It is flexible enough for when I occasionally swap between metric and imperial leadscrews

Also, while the saddle was off the lathe I made a perspex cover for the saddle traversing gears, a very worthwhile mod imho.

Months of perusing the mini-lathe forum **LINK** was invaluable when setting up the little beastie

* Danny M *

When it happened to me, the ribbon of aluminium vapourised inside the controller with a scary blue flash and pop. Opening it up I found no obvious damage to the board : I guess I got lucky and the ribbon shorted out a capacitor and fused before causing mayhem. After removing a few bits of swarf I powered up and found everything was still working.

My cure was simpler than Danny & Neil's. I just positioned short strips of electrical insulating tape around the hole to protect the gap.

I also protected the saddle gears with a bit of meat pie box plastic window rather than Danny's professional perspex. Swarf in the gears doesn't do any damage but the gritty feel is annoying.  It's true - I am a dreadful bodger.

Dave

Edited By SillyOldDuffer on 18/11/2018 10:11:56

                  I never liked the lead screw going through the electronics box. I fitted the speed control circuitry in a new box and mounted it on a spacer. The bigger box also allowed me enough space to use a standard potentiometer with a cam operated microswitch instead of the specified component..

Edited By Anthony Knights on 18/11/2018 12:16:29

Edited By Anthony Knights on 18/11/2018 12:17:08

Edited By Anthony Knights on 18/11/2018 12:17:45

Edited By Anthony Knights on 18/11/2018 12:18:19

Dave,

I never consider anything a bodge if it works and like you out came the roll of tape for a quick fix. I will do a Blue Peter on it though as I have some 1mm thick sticky back plastic which I can fashion a cover from.

Ron

Edited By Ron Laden on 18/11/2018 14:03:58

I fitted one of Arc's lead screw grommets...
**LINK**

Thanks for that John, I didnt realise you could get one.

Ron