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If you consider an extension block on the front of the compound.

Suggest you cut in the dovetails that match the x slide.more rigid.and supports the gib when x slide is fully extended out.

Needs s bit of fine milling to get it correct?

I will try and dig out some photos.

John

On Wed, 9 Oct 2019, 11:11 John Lindo via Groups.Io <bechetboat=[email protected] wrote:

Yes both sides of the RH plummer block.I removed about 4 mm per side if i recall.

IE 2 x the overall thrust bearing thicknesses.

This then also takes up the b/lash as there is nothing the LH end of the screw.Just the plain abr of the screw in a long bore.

I still used the R Bull back lash nut on the RH side, and clamped the coupling around that.

I needed to bore out the coupling?from 12 mm dia to 14 mm dia?? for it to fit. 10 mm to the stepper spindle

the other end of the coupling.

Consider if the screw is straight elongating the 2 support blocks so you have some up and down movement.

but also check the engagement?of the feed screw half nuts.

I am sure you have all this under your bet.

John

On Wed, 9 Oct 2019 at 10:55, les higgins via Groups.Io <leshiggins=[email protected]> wrote:

Hi looks like a good mod looking forward to your pics. I noticed that my Z axis was throwing a bit and I modified the z axis by putting needle bearings in the bearing blocks . The lathe already had? double ball race? thrust washers as standard on the tailstock end. However, I noticed that the leadscrew? is still out about 0.3 mm on the headstock end and it seams the lead screw is either bent or the end shaft is not concentric with the lead screw so I am going to take the leadscrew off and test for straightness .

Regards Les

On Wednesday, 9 October 2019, 07:18:57 BST, John Lindo <bechetboat@...> wrote:

Les

I will send info reference the" conning tower" feed nut this weekend.

Basically a square nut about 20 mm long can be cast iron or phosphor bronze. this has a spud (spigot) sticking up that fits into a hole from the underside of the top x feed slide.

The fit between spud and hole is about .02 mm dia clearance.

There is a chamfered allen screw that keeps the nut attached the the top cross slide.

Either side of the hols for the spigot are holes drilled and tapped for pointed grubs,?

these locate directly into dibbits in the top of the nut face. We can call these jacking

screws for adjusting the other words the nut is tipped thus setting backlash to

almost zero.

The nut cannot shift as basically retained by the c/s screw and will not shift back and forth as?

the pointed grubs prevent this.

This is not a new principle, most high end lathes adopt a similar principle, just that i adopted

this for the mini lathe.The original OE as supplied backlash nut, well say no more.

but totally useless.

My idea has been adopted by 2 other forum members, possibly let them explain more for clarification.

Again, I try and will send info through the week end, but all info available through the Home Shop machinist

I will try and find the date of publication.

Also available I think, in the 7 x forum files. again I cannot remember when, possibly 3 -4 years ago ???

under an article called "swiss cheese" with a zillion more modifications how dare they LOL.

Not sure if you extended the cross slide travel with a block, by doing this I increased the travel of the cross slide operator side by 24 mm, which gives and additional 48 mm of dia that can be turned.

You can also once the compound slide is removed (gr!!!!!!!!!) fit on the new riser block and drill and

tap holes in any position for the tool post stud, this will increase the diameters to be cut vastly

without losing ridigity.?

Currently I have not fitted thrust bearings, i am OK at this moment, but a back burner job.

I have the needle inner and the outer washers,

With b/l under control, the end of the feed screw is held by the oldham coupling (flexible drive) connected

to the stepper motor, and the front of the screw with the shoulder against my new extension block,

there is no movement, but a thrust washer set up is icing on the cake.?

I need to revisit this, I guess i am lazy LOL.

GOWIL?

I also cut a new cross slide screw using 10 mm dia silver steel (drill rod) and the manual threading function

of the ELS, it?s MAGIC.

All food for thought, you have certainly picked up the gauntlet and GOWIL. Very well done.

I just love to read of positive actions by the forum members.?

GOWIL means Get on with it Lewis, form the famous books of the police Inspector Morse.

He had a sergeant who did all the footwork, solving the crimes and Morse would sit in a pub/bar drinking

saying GOWIL can?t you see I am busy.

Have a good productive day

Cheers

On Wed, 9 Oct 2019 at 00:42, les higgins via Groups.Io <leshiggins=[email protected]> wrote:

John?

No I don't know anything about the "conning tower cross feed" would be interested in that. I should get my M10? 1p? LH taps shortly. Like a lot of these mini lathes the cross slide back lash adjustment leaves a lot to be desired even though my machine is a Chester db7 similar to Warco 180 is supposed to be an? uprated design. The cross feed nut is cast iron and only about 15 mm long with some slop. I have seen on youtube a mod on the same lathe as mine that uses ball race thrust bearings? plus an ingenious nut made out of Delrin clamped within a steel square housing of about 30mm long? and about 21mm square don't know about the longevity of the Delrin but I suppose you could make a few of them and change if required.? I am going to have a go at that. Meanwhile I would like to see some pics of your modification and thanks for your interest

Regards Les

On Tuesday, 8 October 2019, 17:58:18 BST, John Lindo <bechetboat@...> wrote:

Les.?

Do you know about the conning tower cross feed type nut I developed for the 7 x lathes.

So simple, but very effective for backlash control.

Let me know, I can send photos etc.

I have 2 x 10 x 1.0 mm LH taps, Richard could of brought one back with him.

cheers

John

Virus-free.

On Tue, 8 Oct 2019 at 11:03, les higgins via Groups.Io <leshiggins=[email protected]> wrote:

Hi John? my RELS is? finished but I am modifying the x cross slide with ball thrust bearings. I have made a new cross slide lead screw from stainless steel? using a travelling steady and a modified nut which I am waiting for a left hand 10 M 1.0 pitch tap? and the bearings from China. The screw cutting was made easier with the stops which I am really pleased? with

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John

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John

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John

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John