CL500M milling

[Danni BurnsParticipant @danniburns84841]

Does anyone have any advice on making the mill head more solid and usable.

I’ve just used today for 1st time and although I’ve done the intended job (simple spanner flats on a 25mm bar) it was painful.
I had to do a lot of fettling with mill block and clamps, vice etc.

I’m concerned about the mill head moving sideways (swinging) and working that limitation into how I approach future jobs (to avoid scrapping material and tools) will mean a lot of up-front effort/work-arounds to hold the job.

I don’t see any benefit to the mill head being able to swing sideways (except out of the way) so maybe locking-up, semi-permanently, that movement would be the way to go.

Anyone with experience of this? Or general tips for using this function.

cheers

 

[Michael GilliganParticipant @michaelgilligan61133]

For convenient reference:

https://www.clarkeservice.co.uk/manuals/metal_lathes/CL430_Metal_Lathe_REV_3.pdf

MichaelG.

.

Edit: __ It appears to me that Lever_3 shown on Fig.13 should in principle provide all the locking that you require … it would therefore be worth investigating the ‘fit & finish’ of various components before attempting to improve  the design.

[David George 1Participant @davidgeorge1]

On larger machines i have worked on they have a taper dowel which is reamed when in vertical position to remove the dowel it has a thread which has a nut on which when tightened extracts the dowel. This stopps the head rotating and sets the head in vertical position.

David

[JasonBModerator @jasonb]

I believe it is actually lever 2 that locks the head, lever 3 rotates the collar on the threaded column to raise and lower the head, see video

The combination machines are not the most rigid so you will have to take light cuts, yes it will possibly take longer than a deep heavy cut but you need to work with what you have got and learn to make the most of it. So fit a smallish say 6mm dia cutter spin it up to cutting speed (2000rpm if the head will run that fast), use as much of the side of the cutter rather than the end and move the work say 0.5mm per pass.

[JasonB]

On JasonB Said:

I believe it is actually lever 2 that locks the head, lever 3 rotates the collar on the threaded column to raise and lower the head, see video

…

Apologies … it was rather early when I posted

I was hoping that the collar acted as a big lock-nut.

Oops !

MichaelG.

[Danni BurnsParticipant @danniburns84841]

We knew what you meant MichaelG

Thanks for all the above comments. I was using a new HSS 5/16 end mill on mild steel. Simplez! ?

I think there is a combination of things, from holding the work and the tool better (I’m sure they both moved), cutting fluid, and taking light/consistent cuts.

None of my vices fitted/bolted very well on the Clarke Mill Block. Seems that piece of Iron girder will come in handy after all!

The head was locked as advised above – but it still moved.

It was my first time using it and I did eventually get there BUT jeez it takes time to find workarounds from the usual/expected approach to doing things. Approx 2 hours to mill what would have taken 20 minutes with hand-file.

Have a great Sunday

[Dave HalfordParticipant @davehalford22513]

Assuming you had a proper milling chuck and vice.

Did you lock all the moving surfaces not in use?

Did you use the apron wheel to drive the cut.

Don’t climb mill on that machine.

Doesn’t the Clarke have a backlash adjustment on the apron?

 

[Danni BurnsParticipant @danniburns84841]

what is ‘climb mill’?

If it is adding cut/depth while milling, I added cut/depth when the cutter past the material.

Yes, feeding by hand. had everything nipped up. and Crossslide locked.

I think more speed would have helped as well. I thnk the max is 1600rpm.

[Dave HalfordParticipant @davehalford22513]

It’s when the mill seems to be self feeding and the cutter effectively tries to climb out of the cut as it pulls it’s self along. It can be a quite violent process if you are taking a relatively large cut that will find any slop in the setup or mill that’s a bit wobbly.

[JasonBModerator @jasonb]

Climb milling is where the direction of the feed may cause the work to be pulled into the cutter or the cutter try to “climb” over the work.

1600 should just be OK with a 5/16″ HSS cutter, this is a 6mm at 2000rpm using 6mm of the side and stepped over 10% of the width = 0.6mm. Conservative feed of 120mm/min. If yours is 4-flute then 150mm/min would be a similar loading @ 1600rpm or drop to 1000rpm and feed at 80mm/min. Nice chips are what you want not dust.

[Howard LewisParticipant @howardlewis46836]

Climb milling is where the feed is in the same direction as cutter rotation. (i e. On a vertical mill, a cutter revolving clockwise, viewed from above, removing metal on one edge of the work, and the work being fed in the same direction.

This means that the cutter will tend to grip the work, rather like a pinion on a rack, and pull the work along.

With hobby, or any machine lacking backlash elimination, this is NOT good.

It might produce a better surface finish, but the cutter is likely to grab the work with disastrous consequences.

So, normally the work is fed against the cutter, so that the cutter tries to push the work away.

Hope that this makes it a little more plain.

Have heard that the CL500M is prone to movement. If the column cannot be locked firmly enough, maybe an additional clamp for the column could be added

Adding a clamp, with positive locking with a pin would restrict the versatility of the machine, because the column could only be moved up or down in fixed increments, of say 20 or 25mm. (for a 6 or 8mm diameter locking pin) because of the spacing of the holes made in the column.

You might be able to get away with a smaller diameter pin,.

What is the pitch of the thread?

You might be able to drill a small hole, for the pin, at the bottom of the thread, to reduce the increment to the pitch of the thread

Even a 3mm pin, allied to the existing locking arrangements may be sufficient to prevent the head from swinging.

Sounds like Catch 22 in that ideally, you need a mill to keep all the holes in line.

Possibly:

Hold the column between chuck and Tailstock; mount a “jig”. with a hole at centre height, in the toolpost, and having aligned on one thread, use the Leadscrew to increment the Saddle after each hole has bee drilled.

HTH

Howard

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