How to lubricate pulley shafy bearings?

This topic has 10 replies, 7 voices, and was last updated 5 January 2020 at 10:19 by Neil Wyatt.

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4 January 2020 at 16:13 #444631
Chris TickTock
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@christicktock
Hi I got given this unbranded vintage old lathe. It has a Goodell Pratt 3 jaw chuck and cross slide and pullies, no tool rest. just cleaned it all down.

I am thinking as i love old stiff and was also given a small singer motor to use it as a small grinder. Can anyone hazard a guess if i should oil the bearings via the brass pulley screws or just grease or oil them?

Spent some time trying to work out the threads for screws holding the chuck . I think they are 3./16 24 which if American would likely be American Unified course which means BSW will do?

Chris
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4 January 2020 at 16:13 #10010
Chris TickTock
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@christicktock
4 January 2020 at 17:57 #444645
not done it yet
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@notdoneityet
That’s not a pulley shafy, it’s an adept. Neil will know all about those – they are his favourite.🙂
4 January 2020 at 18:04 #444648
Chris TickTock
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@christicktock
Hope Neil has a mind to posting then. I have investigated further found little holes at the bottom of the screw holes where the 2 screws are so this I think is where oil goes. but is that it for lubrication on the pulley shaft or whatever it should be called??

Will synthetic oil do or is that likely to cause WW3./

Chris

Edited By Chris TickTock on 04/01/2020 18:06:13
4 January 2020 at 18:42 #444654
JasonB
Moderator
@jasonb
I thought the Adept had a gap along the middle of the bed rather than a flat dovetailed one, a flatter top to the bearing housings and a cast foot in the middle. The gap allows sea water to flow through so it sinks to the bottom faster.

Chris is there anything written on the other side as the maker's name was often cast in.

A nice little project for you would be two brass oilcups to replace the screws, doubt the bearings will be capable of grinding speeds though

Edited By JasonB on 04/01/2020 18:45:14
4 January 2020 at 22:05 #444682
Chris TickTock
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@christicktock
Posted by JasonB on 04/01/2020 18:42:03:

I thought the Adept had a gap along the middle of the bed rather than a flat dovetailed one, a flatter top to the bearing housings and a cast foot in the middle. The gap allows sea water to flow through so it sinks to the bottom faster.

Chris is there anything written on the other side as the maker's name was often cast in.

A nice little project for you would be two brass oilcups to replace the screws, doubt the bearings will be capable of grinding speeds though

Definetly no makers mark. Looking at your remark about suitability as a grinder what speeds would such a lathe normally be expected to run at?

Chris

Edited By JasonB on 04/01/2020 18:45:14
4 January 2020 at 22:56 #444685
Clive Brown 1
Participant
@clivebrown1
Grinding spindles run typically at several thousand rpm. For example, my bench grinder with 150 mm wheels operates at 3000rpm. My Quorn T&C grinder, with 100 mm max. wheels is ~4800 rpm.

I don't think that your spindle could achieve anywhere near those figures. If a grinding wheel is operated too slowly, it cuts "soft", with relatively rapid wear and consequent loss of shape. 1500 surface m/minute would be reasonable for tool grinding.

Also, a sewing machine motor is not the best for a grinding spindle. It's probably a brush type universal motor for which the speed is poorly regulated and very load dependant, at worst the wheel could overspeed. An induction motor, with a flat speed/load characteristic is commonly used.

Clive
4 January 2020 at 23:38 #444692
Keith Long
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@keithlong89920
Chris that looks very much like the bed for a Drummond "little Goliath" see here . If so putting it on EBay might result in more than enough for you to buy a small grinder.
5 January 2020 at 03:02 #444703
John Reese
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@johnreese12848
In all probability the screws are Whitworth. If built in England it would not likely have UNC threads. If you want to use UNC the proper designation would be 10-24. The 3/16-24 was a stove bolt thread that went obsolete many years ago, about when coal stoves in kitchens fell out of favor.
5 January 2020 at 09:43 #444723
Chris TickTock
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@christicktock
Thanks Guys and especially Keith who I am thankful for pointing me in the right direction is right, it almost certainly is the Little Goliath. Makes little difference I will keep it and just preserve it. What threw me over whether it was US was the Goodel Pratt chuck but that was an add on sourced from the states by either manufacurer, distributor or owner.

Clives point on constant speed is valid. My slow speed diamond sharpener is run from a DC motor with constant speed via its speed controller torque is constant as power is either full on or off being a digital controller (pulse width controller. So I could source same motor and controller if so desired.

But I wonder if we think of people in the 1920's how many might in fact on such a small lathe. have used a singer motor? As I have one 9not yet tested) I will churn this over it will come down to usability verses originality perhaps?

Chris
5 January 2020 at 10:19 #444732
Neil Wyatt
Moderator
@neilwyatt
Yep, not an Adept.

Sewing machine machines are a bad choice for grinders full stop, you definitely want a synchronous motor if you don't want to be picking bits of grinding wheel out of your head.

There was one design in ME about 60-70 years ago taht used one, fitted with a hand adjusted brake to stop it overspeeding. Seemed the dodgiest setup for a grinder I have seen.

Neil
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