Member postings for Me.

Pheeeewwww - Thanks, but I think I would prefer to buy a good used chuck with extra jaws than spend that sort of money on a set of jaws.

Recently the new owner of an old Harrison 140 lathe (@1972).

Having spent sometime now cleaning, repainting and generally making good 40 years of use (from what I can tell only slight use) I took my first few cuts, and all is well and I am extremely happy with it ---- BUT, as there's always a BUT -- I have a very small annoying problem.

I have turned a few test pieces over the past few weeks and was confident to try my first real go at making something I needed, modify a 2.5MOD spur gear to fit in my Herbert Mill table gearbox.

All was going well having first faced it to depth - bored it to the spindle size and even cutting in a key way. I then had to turn the piece around to reduce the boss of the gear by 2mm - this is where my annoyance started.

When I purchased the lathe it came with boxes of bits and pieces and in amongst the bits where outside jaws for my chuck, i remembered picking them up from under all the none useful parts and muttering to myself "Oh that's good at least Ive got those" I promptly cleaned them and gave them a good rub with a very oily rag and put them away for an occasion at which I would need them - the occasion had arrived, sooner than I would have imagined but now was the time to change my chuck jaws to help me hold the spur gear - I am anticipating everyones thoughts at this point - and yes you are correct - they are not the right jaws.

Or should I say, they are the right jaws, well 2 of them are the 3rd is also a 3, if you get my jist. I have a 1 and two 3's, obviously they don't work with the chuck so my spur gear had to be held very strangely in my internal jaws - still managed to do it with a few thou to spare .....

Looking through a well know auction site there are plenty of jaw sets for sale at the moment but nothing that I can see that are the same dimensions as my chuck - 8" Pratt Burnard -

I read that its not a good idea to use chuck jaws that weren't supplied with the actual chuck at purchase, I can only think this is down to them being ground to suit the chuck.

If I do manage to find a set of jaws the right dimensions what would be the pros/cons or is it just all Cons......

Obviously if anyone has a set of jaws that would suit then please let me know.

NB - I'm a beginner - reference to doing things wrongly as mentioned above is my learning curve.

Edited bit - If anyone has a 1 and two 2's I know where your 3rd one is !

Edited By Me. on 05/02/2021 14:53:39

Thanks for the reply - but mine doesn't have a motorised quill or Knee raise/lower. My Mill has spindle drive motor and table feed motor left/right.

There must have been a reason for them to design the machine to have the main spindle motor to reverse.

NB: New Rotary switches installed and have just order two new Auxillary contactor blocks NO/NC type to control the other contactor. I think I will soon be ready to use the Mill - after almost 6 months of restoration and heartache.......money...... time....and trouble. But its worth having this almost 70 year old machine back up and running.

Thanks I will get two more switches and have each contactor control a separate motor - with your help I will get this done.....

Thanks Les _ I can do that I have a spare contactor the same as the picture.

Will I need two more on/off buttons as well ?

My Idea was

1.Press the button to turn the contactor on

2.Switch the main motor on (rotary switch)

3.Switch Table feed on (rotary switch)

4.switch to the "0" position when finished cut

5.Press the off button to turn main power off.

*i'm now in need to know the answer to Larry's Question - why does the main spindle motor need to run in reverse ???*

It has the option too on the "old switch panel" but when would you ever need to make a cut with the spindle in reverse ??

HI Les

Many thanks again for your very easy to understand description and diagram. I will do as suggested.

As I will have two rotary switches - one to control the main spindle motor and one to control the table feed, do I take a separate feed to each X point on each switch or do I add the switches in series.

i.e "Brown (feed) - X-Y-X-Y - Stop".

Steve

Two pictures of the contactor and switches as fitted to my Mill.

Brown Black and grey input from the mains at the top.

the 3 pairs of yellow blue and red are the feed to the two motors. Which I am fitting the new rotary switches too.

The brown leads go to two momentary switches the green one energizes the contactor and the red one turns it off.

The blue wire sticking out at right angles is the neutral.

Where do I need to break the leads to add my new switches as per Martins wiring diagram ( X - Y connection)

Or do I need to replace the momentary switches for something else.

Wow Martin - Thanks- that is exactly what i needed - it is so much easier to understand when written down like that.

I can't thank you enough -

I wonder if you could do one with the other option with the It breaks the feed to the coil on the contactor as suggested by Les

Hi John I just went on Ebay and inputted - 3 phase motor reversing switch.

I had thought of that option and I suppose it would be safer I suppose if I did it that way - For some reason my PC isn't allowing me to upload any photos - pictures so I can't draw out what I have got but its very basic wiring.

3 phase wires + Neurtal which goes into the coil of the contactor

1 phase wire goes into the coil of the contactor (hager - 240v coli) and into the switch - one "off" and one "on" wired in series.

When I press the "on" button it energises the coil which brings in the contactor - which then feeds my (very) old existing lever switch. Up for forward and down for reverse.

To stop the motor I bring the lever switch to the middle which kills the power to the motor and then I press the "off" button.

I was just getting my head around the Linking terminals now it looks like I'm gonna have to add more....

Ive not brought the rotary switch yet so if i need a 16 terminal switch then that's ok.

Thakns again for all this info. Just to clear this in my mind - where you say "link" you mean add a link wire between the terminals. ?

My machine has an On Off Button which controls a contactor which then send the power to the old switch - No VFD.

Is there any chance of a small schematic diagram ?

Just to note I had already Rulled out the "one line directly to the motor" option as I don't really want the motor to be live all the time its switched on.

For those that asked the truth table for the switchI want to use.

Many thanks for the very precise instructions. Exactly what I needed.

Thanks - Ive already had a look at the blue line page but still means nothing.

All I know is I have 3 wires from the contactor - 12 connections on the switch - 3 wires going to the motor (not including the earth).

If i connect the feed from the contactor to 1 3 5 where do the wires that feed the motor go ?? 2 4 6 ?? what are the other 6 connections for ???

Yes true 3 phase supply 400v supply

This is the switch - sorry i meant 12 connections - the description in the blurb says its for a motor F&R switch. I just need to know what connections to use - The truth table indicates which connections make and brake but I can't work out what is what in layman's terms.

I want to fit a new rotary 3 phase motor reverse switch to my Mill.

Ive found a switch which is suitable but need advice on how to wire it.

The switch is an on-off-on rotary with 12 positions.

I have my 3 wires coming from the contactor, what goes where into the switch and what positions goes to the motor to enable it to run forward and then to reverse.

Yes it is the Herbert Mill - One of the gears does have 10DP stamped on it - Is this the "type" I need to be searching for

I have looked at mod 2.5 and they seem to have more ratios.

Can anyone suggest a supplier ?

I am in need of some help in working out which type of spur gear i need. ive trawled the internet for some basic info on spur gears but it rapidly gets very technical and gets its very frustrating with all the different types there are.

My Milling table has a small gear box which uses spur gears to drive the gear box -

the ratios are

34/14 = 1/2" per min

29/19 = 3/4" per min

24/24 = 1 1/4" per min

19/29 = 1 7/8" per min

14/34 = 3' per min

I only have the 34/14 ratio so i'm looking to get the 29, 24 (x2) and a 19 toothed spur gears.

The centre between the spindles is 61mm (2.375" - 2 3/8ths) approx.

Can some one please advise which type of spur gear I will need and what are the crucial dimensions I should be looking for.

Thanks one and all for the most informative responses.

I have had a look for the Clarkson type holders but the the 30 taper seems not that easy to get. The 40 taper seems more available - I think the ER system might be the better way to go.

Thanks again