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Member postings for Darren Keats

Here is a list of all the postings Darren Keats has made in our forums. Click on a thread name to jump to the thread.

Thread: Mini lathe feed
10/02/2021 19:26:09

https://www.arceurotrade.co.uk/machineguides/Super-C3-Half-Nut-Conversion-Guide.pdf

may as well do this conversion to 2 half nuts while im at it

10/02/2021 18:35:39

Thankyou Michael , just watched that 👍

Edited By Darren Keats on 10/02/2021 18:35:50

10/02/2021 17:28:03
Posted by Journeyman on 10/02/2021 16:34:31:

This is a still from the recent video:

halfnut2.jpg

Firstly the half nut is full of crud and needs a good clean. The block on the right, retained by two Phillips head screws and bent washers is loose. I am assuming this is some sort of gib strip and needs to be adjusted so that the half nut slides smoothly up and down. At present the half nut is waving about up down and sideways it all needs disassembling, cleaning and the putting back together with the gib strip properly adjusted although I can't quite see how the adjustment is made, presumably a couple of allen screw on the right hand edge. The whole thing is a fine example of poor engineering (sorry).

Once that is done the guide on the left needs adjusting so that the lead screw just bears on it so that it prevents the leadscrew deforming when the half nut is engaged. Although again I can see no easy way to make such an adjustment.

Good Luck

John

yes i agree ,it needs disassembling, but im not confident on getting this adjusted correctly

10/02/2021 17:25:38

Ok , firstly thankyou howard Lewis & journeyman 👍🏻
its an axminster sc2 btw

i cleaned out the half nut threads with a metal pick , it was full of hardened crud!
the bars with 3 Allen bolts were both loose , but i think this needs attention after.
i put it back together and now its working , but i messed with the gib screws and need to set these back again

when i engage the feed now it sometimes clunks a bit , but i think this is a gib screw adjustment issue?
i will take you suggestions on the gear changing that should suit pen blank turning , time to figure this out now as never done this before , i think i have some alternative gears

10/02/2021 11:44:30

Ok , update , i took the carriage off to see better . https://youtu.be/Rwjb8xX0Z7I

Any suggestions to what is wrong?

14/01/2021 17:39:30
Posted by Brian G on 14/01/2021 12:58:30:
Posted by Darren Keats on 13/01/2021 17:44:29:
... did try to cut a bit too much on the part i was making and thats what made it stop operating properly ....

It might be worth looking at the support bracket at the right hand end in case it is adjustable, as with one half nut the leadscrew may just have been lifted out of place.

Brian G

I Will check that 👍🏻

14/01/2021 17:39:03
Posted by Howard Lewis on 14/01/2021 12:16:18:

If you want a fine feed for ordinary turning, the changewheels need to be selected to maximise the reduction ratio between Mandrel and Leadscrew.

For the C2 or C3 mini lathe this would entail a 20T driving a 80T which is compounded with another 20T to drive a second 80T on the Leadscrew. This will give an overall reduction of 16:1 so that for each revolution of the chuck, (with a 1.5 mm pitch Leadscrew ), the Saddle would move by 0.09375 mm or 0.00370 inches. For a 16 tpi Leadscrew the movement would be 0.0039 inches per revolution.

Direction of travel will be decided by the setting of the tumbler reverse, (or direction of motor rotation )

Howard

Thats far too advanced for me to understand 😂

13/01/2021 17:44:29
Posted by Michael Horner on 13/01/2021 17:40:33:

**LINK**

Hi Darren

If you look at picture 29 it only shows 1 half nut.

Cheers Michael.

Ah ok , thats what i have , maybe this part is worn out or the adjustment is wrong . I did try to cut a bit too much on the part i was making and thats what made it stop operating properly . It was just a scrap part i was working on and wanted to remove acrylic quickly, obviously too quickly 😫

13/01/2021 17:32:06
Posted by JasonB on 13/01/2021 17:15:25:

This is what should be happening

There is no top half that i can see . It must be stuck up out of view as it has been working up until today

13/01/2021 17:14:11
Posted by JasonB on 13/01/2021 17:07:23:

Check that the top half of the nut is moving down like the lower is moving up.

Also try it when the lathe is running slower and make sure the carriage lock is not done up.

Edited By JasonB on 13/01/2021 17:12:03

There is no top half, just this lower part of the half nut . Maybe its stuck above but i cant see it?

13/01/2021 17:13:01
Posted by JasonB on 13/01/2021 17:07:23:

Check that the top half of the nut is moving down like the lower is moving up.

Also why have you got it running so fast if it is for feed, would even cut a very coarse thread at that rate.

I use it for shaping acrylic bar, so it just needs to move across quickly to get the job done level, as with the manual wheel its a bit jerky. I have never cut metal on it , just to make mm perfect acrylic pieces similar to pen blanks

13/01/2021 17:10:51
Posted by Martin of Wick on 13/01/2021 14:34:11:

You need to check the geartrain/change gear set up behind the left cover.

1 with lathe unplugged, first release quadrant to free change gear mounted to leadscrew from any other gears in the train.

2 turn the change gear on leadscrew manually to check leadscrew rotates, if so, engage carriage feed lever to check for expected movement forward and reverse - if carriage is not moving then investigate for correct movement of half nuts (by peering at right end of carriage with a torch to confirm that the half nuts move together and apart to clasp the leadscrew).

3) if that checks out alright, check that the change gears you expect to have in the train can be made to mesh correctly and check by rotating chuck by hand to confirm motion all through the gear train to the leadscrew - if not look for change gear mounting issues or potential damage (grub screws or nuts to tighten etc)

4) check operation of tumbler reverse jockey wheels - correct engagement etc

5) if all the above is Greek to you, download this manual....

g0765_m.pdf (grizzly.com)

Edited By Martin of Wick on 13/01/2021 14:36:51

this is a very useful download for someone like me who needs to identify what parts are called, appreciate this👍🏻 And to everyone else who is trying to help me 🙏🏻👍🏻

13/01/2021 17:04:58

I did another video , thankyou guys for all your replies so far . If I understand correctly should there be another top part of the lower half nut?
https://youtu.be/fAt4H0ad9lg

Edited By Darren Keats on 13/01/2021 17:05:33

13/01/2021 14:01:54
Posted by Neil Wyatt on 13/01/2021 12:36:42:

When engaged the wheel won't work and vice-versa.

The half nuts are adjustable in several ways, there is also a hidden grub screw that controls how closely they mesh (Incidentally Ian Bradley suggested such a screw as an upgrade for the S7).

Neil

I was not clear, i ment i can use the lathe with the manual wheel, but it will jot move automatically. Also my lathe will not engage reverse feed fo some reason-it never did ?

13/01/2021 14:00:18
Posted by John Rudd on 13/01/2021 11:15:09:

Either the lever is not engaging the half nut ( not adjusted correctly ) or the half nut is worn

Edited By John Rudd on 13/01/2021 11:17:31

I will investigate this , no idea what the half nut is but i will look up on the Internet so i know what im looking for 👌🏻

13/01/2021 13:58:54

Is the answer in the word "lift". The lever should be pushed down to engage the leadscrew.

Keith

My mistake , i was not by the lathe when i wrote this , i could not remember which way engages 🤣

13/01/2021 10:56:38
https://youtu.be/e7Ra4Yh3B-k
13/01/2021 10:44:02

Hi again, ok after fixing the potentiometer with your help i now have an issue with my feed . The long screw bar turns , but when i lift the lever it does not engage and move along like it should . I can move along with the wheel but not the automatic feed

Thread: Mini Lathe problem
29/12/2020 10:13:46

Thankyou all for your replies 👍🏻

29/12/2020 10:13:14
Posted by JasonB on 29/12/2020 07:00:54:

get a complete unit from Axminster or the spares supplier already mentioned may have a suitable one but check first..

Edited By JasonB on 29/12/2020 07:02:00

Thats what i just did , £25 from axminster complete with circuit board

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