EasiMill backlash adjustment

[XJ5373]

Hi,
Can anyone advise on the approach to taking out backash on the EasiMill X and Y axes. I have a few thou backlash in both axes and would like to take this out if possible as I am machining some round things that do need to be properly round.
Are there any assembly drawings or maintenance instructions on the site anywhere I could reference?
Thanks
Ian

[Martin]

You will need to adjust the tab nut & washer.

If you remove the motor & pulley from the leadscrew you should be able to see the tab nut & washer. You will need to release the tab on the washer then tighten the nut then lock the washer.

[XJ5373]

Ok thanks - I have started looking at the X axis - is that lock nut and tab washer at the drive end or at the handwheel end? Same question I guess for the Y axis
Ian

[XJ5373]

Got it now thanks - the nut is behind the pully at the drive end on the Z axis.
Ian

[XJ5373]

My previous message was meant to say on the X axis - I adjusted the nut and have a complete cure on the X axis but the Y axis is putting up a fight. I have adjusted the nut and am conerned that I might be over tightening, but I am still left with some backlash - is the ball screw nut adjustable in any way?
Ian

[Martin]

It may be that the gib strips need adjusting.

Can you get hold of the table & see if there is any "slop" in it?

[XJ5373]

Ok - So I backed off the nut on the lead screw and took it back up again to the point where the ball screw shaft just doesn't move when switching from clockwise to anticlockwise roataion - I think that this is now properly adjusted. Next to the taper gib - played with this quite a lot. Adjusting until you feel tighness in the slide took a lot of adjustment and the apparent backlash increased. Coming back out I adjusted until I could twist the table (rotating about Z azis - you can measure the movement and hear the oil film break away as the table moves), then pushed the taper gib back in until this just went away. I still have my backlash. It looks like a stick slip effect with the ball screw and nut winding up by a coupe of thou (a few degrees) before the table moves.
Is the nut definitely not adjustable?
Ian

[Denford Admin]

Is the nut definitely not adjustable?

Not 100%, but probably not. Maybe it needs a new nut, or the screw is worn out in the middle ?
Easier said than done, but have you checked all the nut-housing and housing->table screws are tight ?
We've very rarely fitted twin nuts and even those weren't pre-load adjustable.

[XJ5373]

Hi Denford,

Just been fiddling with it now - the X direction looks to have two "devices" on the ball screw with a gap between them - no sign of anything to adjust - although adjustment not needed of course. The Y axis is tricky to get to see but looking from the front it looks like a flanged device just with mounting screws (cap heads with plugs) - looking from the back is far more difficult (could do with a miniature assistant) but there does look to be a copper tube coming back toward the column with an open end - is this part of the lubrication system that has come off?

Are spares available still from Denford or it is a case of trying to find something equivalent? Are there any drawings on the site anywhere?

Ian

[Denford Admin]

We will have no spares for easimill, mechanical or electrical.
Unfortunately, anything I scanned for the easimill/easiturn is already on the site and the maintenance manuals I've seen only cover the control and electronics.
Maybe the mechanics were bought in from the far east ?
Try sending a PM to AndyB asking for more info on Easimill mechanical drawings...he knows more than we do about the history of these things

[Andy B]

Ian,
I've never seen an Easimill close up, nor have I ever looked in any detail at any drawings for them - my knowledge is really on the manual machines, not CNC.

I'm led to believe that these machines were based on an imported (Taiwanese - before they got too expensive, like the Chinese are now getting!) manual mill - as described in the manual here:
https://www.denfordata.com/pdfs/T1P-Turr ... achine.pdf
So it is probably worth seeing if the slides / screw fixings in the manual are anything like yours.

I think I may have some Easimill drawings - I'll try to have a look in the next few days.

Andy

[Andy B]

Had a look through yesterday, and the bad news is that I have no assembly drawings at all for the Easimill.
There are a few component drawings that were mixed up with others -these include leadscrews, handwheels and some associated bits, but nothing obviously showing bearing or nut adjustment.
I didn't have space to take all the drawings, so I generally left the CNC stuff behind - except (as I now discover) the EasiTurn, which continued using the 'BVS' drawing numbers from the manual 280 series lathes.

Andy

[MHJ]

Here are 3 photographs of the Y axis ball screw and nuts. The nuts are by Warner Electric, the front (pulley) end being RM 2505 UF, the rear one is RM 2505 A. They are non-adjustable, have no pre-load and (sadly) no wipers.

[XJ5373]

Hi,
This is really useful - rather hoping you might post some pics of the X axis arrangement and details of the nuts as you go. Do you have any plans to replace the screw and nuts or are yours in good shape?
You are clearly in the middle of a refurb - is this a hobby or something you do for a living?
Ian

[MHJ]

Hello Ian.
I am in the middle of a refurbishment of this Easimill, the base, column and knee were painted yesterday and it's a hobby rather than a job.
I'll take some pictures tomorrow of the X axis twin ballscrew and nut arrangement. Anything else on this machine you would like a photo or details of?
Regards,
H.

[XJ5373]

Hi,
Just the ball screw details on x and y I think - I would like to try and improve things on my machine so if you had any thoughts about identifying alternative screws and nuts - that would be useful. Apart from the control system of course my machine is pretty much as it arrived but with a bit of beefing up in the Z department as this axis was very floppy.
I was half hoping you were in the refurbishment business - I would like to get my spot on......
I have been half looking at replacing it with something better, but I am not sure that there is anything out there. I could go a bit bigger up to say Bridgeport size, but I am struggling to find much in that category.
I am in Cheshire if you want to compare notes on anything - my machine is busy on and off doing 3D CAD CAM work.
Ian

[MHJ]

As you say Ian, what else is there out there? I bought a manual Bridgeport, may be 6 or 7 years ago from a slide way grinding Company in Colsterworth, Ebay £187, complete, with all the slides reground, but in bits. I thought about converting it to CNC but a machine of that size really wants servo rather than stepper motors and that was way outside my budget. With a few odds and ends from Hendrix in the USA, that's now the biggest machine in my very cramped workshop.
I bought the Easimill because my Boxford 260 VMC albeit a cracking good machine, does not have the capacity for what I now want to do, so that, with many regrets, has to go.
I've been writing up the Easimill rebuild and if Admin sanctions a new thread called "Machine Number 12075/E/M October 1985 ...the Rebuild" then watch that space !!!
Regards,
H.

[MHJ]

X axis nuts are Warner Electric series RM type 2025 UF, attached in their carriers to the saddle by 2 capscrews each end.
I haven't looked to find replacements.

[Denford Admin]

I've been writing up the Easimill rebuild and if Admin sanctions a new thread called "Machine Number 12075/E/M October 1985 ...the Rebuild" then watch that space !!!

Go for it - it'll be very useful either in this section of the User Stories/Projects one.
If it goes in here I'll make it sticky so it stays at the top of the section as, like Dazz's Viceroy posts, they are interesting to all users of a similar machine (whether rebuilding or not)