Clarke CL500M half nut conversion

Hi Stu

Regarding the struggle while swapping chucks. You recommend replacing these bolts with studs and nuts?

Mini lathes use studs and nuts, for reasons of space.

But studs remove the problem of the eventual wear of the threads in the chuck. At least a worn or damaged stud can be replaced pretty easily.

But you can get very frustrated searching for dropped nuts!

Danny M2Z made a very useful, simple, gadget for holding the nuts for fitting or removal.

It starts life as a bit of flat metal Two cuts, one bend and a bit of filing and dropped nuts are very rarely a problem.

There is no reason why it could not be scaled up, to suit fixings larger than M6.

Howard

Yes that's right. It's easier to slide the studs through the holes which will then help support the weight of the chuck while you fit the nuts on to the studs.

Ref your drawing, as John mentioned it is important you have a boss on the front of the back plate you're going to make so that it centralises and supports the 4 jaw chuck, just like there is on the front of the lathe chuck mounting plate. That's what I couldn't see on the cross section in the drawing.

Once you remove the 3 jaw chuck you will see the boss and the recess to take your measurements from for the rear of your new back plate. For the boss on the front of the back plate you need to measure the recess in the back of the 4 jaw chuck.

Hope that makes sense, I'm not particularly great at explaining things!

Stu

Hi Stu

Yes. Makes sense. I think doing the drawing was worth while now.

I will measure all up and modify the drawing. I'll ask you and John to check then. Hopefully other will be able to use.

Howard

What's this M2Z thingymabob. Have you got a pic?

cheers

Hi Danny,

There was an article, some time ago in MEW, by Danny M2Z. Think that he lives in Oz or NZ.

I made one out of a bit of steel strapping. It is that simple, even I can make one that works!

One bend is to act as a short tongue that enters the nut as it comes to the end of thread, and by holding the nut against the main part of the tool, prevents the nut from falling off.

SO simple, and SO effective!

I'll take a shot of it and send it to you.

This will be for M6 studs and nuts. It allows the nuts to be tightened or slacked with a 10 mm A/F Open End spanner, starts or completes the process, leaving the rest to be dome with fingers, without dropping the nut.

Saves a lot of frustration (and wear on the threads in the chuck ).

Just needs scaling up for larger size studs and nuts.

Howard

Danni,

My Machine Mart 4 jaw has no makers mark and is mounted onto a steel back plate the OD of the chuck and back plate are both 149.60mm dia, the back plate is 12mm thick and the recess is 3.55 mm deep and 99.90mm dia and the PCD of the three tapped holes to mount it on the spindle is 131.6mm dia.

The hole in the centre of the back plate is 32mm.

Hope this helps,

Martin P

Edited By martin perman on 23/05/2021 14:09:44

Thanks Martin

I will update my drawing with those details and see where Im at.

I bough the cast iron blank. Unfortunately it has a big boss in the middle that to get rid of. May be messy like Stu mentioned.

cheers

When machining cast iron, I place a powerful magnet under a sheet of newspaper, or cloth (So that it does not get caught up) where it is likely to fall, to attract as much as possible of the swarf.

It will not catch all, but it makes the job a little less filthy!

Obviously do a really thorough clean up afterwards.

Howard

I hadnt thought of magnets, but have a couple so will definitely try that out.

I do intent to run a vacuum, hopefully I can position the nozzle to catch the majority.

cheers

Hi guys

Can you please tell me how you split your half-nut PB block?

cheers

https://www.youtube.com/watch?v=kAKPhE9HisI&t=59s

Stu

It say 'I then cut the half nut in two'.

Hacksaw Danni. JH

Sorry Danni, I didn't read your question properly. Like John said a hacksaw or if you have the luxury of a bandsaw even better. Don't worry too much as the two halves should fit together however you cut them and you need a gap in between the two halves.

Stu

Hi John/Stu

I dont have the luxury of saw. I dont even have the luxury of a 2"x2"x2" lump of PB yet (which is circa £45 - any ideas on getting a cheaper lump much appreciated)

I was thinking whether to saw and clean-up. Then was thinking about slitter-saw, but worried about gap.

That lead me to thinking whether I should cut first and drill/tap afterwards (thus providing the possibility of using smaller pieces of PB).

That then led me to wondering if a gap was required.

So in your humble opinions, would you advise against splitting first; and what would be the optimum gap (as in either case, this could always be skimmed last should you now consider with hindsight that a bigger/smaller gap is preferred)?

cheers

I got a piece of 1 1/2" x 1 1/2" x 100mm brass off ebay for £20. Enough to make 2 nuts if need be!

I would definitely cut the thread first before splitting the nut, no chance of the two halves moving while drilling and tapping. Just the width of the saw blade should give enough gap for adjustment as the nut wears over time.

Stu

Thanks stu

I'm paying visit to scrap merchant this week so will take cutting lists with me to do few jobs .

on another note, ive noticed that I need to remove an angle iron type lead screw guard in order to install a dti clamp.

Did your machine have One of these lead?

No, whoever had the lathe before me had removed the lead screw cover

Hi all

Im looking for a TR20 x 2 Trapezoidal Metric HSS Left Hand Thread Tap

Anyone got used to sell?

cheers