ML7 saddle hand wheel issue

Hi, I’ve just taken possession on a 1950’s ML7 to accompany my Bridgeport mill. I have found that the carriage hand wheel (the one on the side that moves the carriage back and forth) is exceptionally stiff, so much so that at times I need two hands to turn it. It seems to be okay when engaged with the screw gears and when disengaged the leadscrew turns freely. Could someone please give me an idea as to what the problem maybe? From what I’ve seen the the wheel should move the carriage with little effort. Thanks.

could it be swarf in the pinion which engages with the long rack beneath the bed.

Frank

Just a guess. Maybe the half-nut mechanism swivels due to wear or maladjustment and wedges.

If the nut is at all visible where it engages the leadscrew, it might be possible to see it tilt and wedge when the handle is turned. The state of the half-nut threads is worth checking. With luck stuffed with easily removed swarf, on a bad day, the threads are badly worn.

I don't know how ML7 half-nuts are adjusted. Myford owner required!

Dave

Doubt if it's the half nuts most probably swarf filled hand wheel pinion and associated gears /rack. Easy to remove and clean up, you could clean up the half nuts at the same time and also see how they are adjusted. Good job its not power crossed that would be a different ballgame.Look at Myfords site the exploded parts diagram is helpful.

Probably a stupid question but you don’t have the saddle lock tightened do you?

Its the bolt on the back of the saddle to the right of the cross slide.

regards Martin

😎😎 I did look at that, thanks anyway.
I think it will be wise to strip it down and clean it up and go from there.

thanks all.

Mark

Are the gibs too tight?

I would not go stripping it down at this stage. It is not a beginner's job and can cause more problems than it solves. The stiffness will be some simple thing. All you need to do is go through and check/rectify the simple things one at a time without disturbing the whole show..

Tap on the carriage lock at the rear after loosening the locking bolt to make sure the lock disc is not jammed up.

Squirt WD40 in around the handwheel pinion and shaft.

Check there is a bit of end float slack on the handwheel pinion shaft. I don't remember now if that handwheel is held on by a pin or a grub screw. If a grub screw, you could move the handwheel out a fraction to create clearance.

Use a brush to clean any swarf from around the pinon and rack.

Check the carriage gib adjuster screws and readjust them a bit on the slack side for now. You can tighten them up later after free movement is achieved. And check if the previous owner has added the common extra locking screws in between the original gib screws. These could have been left half tightened etc. A common mod when milling in the lathe as it gives a better, more accurate lock than the rear bolt.

Check the felt carriage/bed wipers and remove them for cleaning if full of swarf.

Loosen the screws holding the rack that the handwheel pinion engages with and allow it to move upwards to create a bit of clearance between rack and pinion.

Check the Allen screws holding the apron to the saddle are tight. Or if they are tight, try loosening them off and see if that frees up carriage movement, indicating that some shimming is needed between the saddle and apron.

Let us know how you get on.

Edited By Hopper on 09/01/2023 22:07:17

Just undo the four cap head screws in the top of the saddle and remove the right hand lead screw bracket and the apron will drop away, you will then be able to see the gear that meshes with the rack.

It might just need one or both of these locking screws backing off

Or one of the gibs screws like the one next to it with the hex lock nut.

Hi there, all,

I don't think anyone's mentioned it so far but the ML7 saddle hand-wheel doesn't engage directly with the (inverted ) rack, There's an intermediate gear ratio to ensure that the saddle moves towards the head-stock when the hand-wheel is turned anticlockwise, i.e. the top of the hand-wheel is moved towards the head-stock.

However, that gearing is fairly well enclosed and I would be surprised if any swarf could get in there.

I presume that Beeston Myfords designed the ML7 with an inverted rack to minimise the likelihood of foreign matter lodging in the rack teeth.

Best regards,

Swarf, Mostly!

Have a look at the drawings on here.

https://www.myford.co.uk/acatalog/Apron-Assembly-For-Machines-Prior-To-Serial-No.-K111727-Refer-To-Section-D.html

David

So, took the apron and saddle off and it appears my father in law used grease in the nipples instead of oil, consequently it was a gummed up. Gave it a good clean cleaned out the oil ways and the nipples, slide way oil on the bed, I used HT 46 instead of 32 as that was all I had. All seems perfect now. I need to get an oiler from somewhere and some HT32 and all should be good. Thanks everyone for your help.

Good result. The best oil guns come from Press Parts at pressparts.co.uk. The cheap ones including Sealey tend to leak.

There is no engagement-depth adjustment for the half-nuts on the standard ML7 apron.

There are two small screws in the left-face end face of the apron, doubling as lead-screw shield fastenings. These affect the fit of the slides in their vertical guide, so might have a small effect on the pitch matching, depending on wear..

I have had mine apart to fit an older-pattern gearbox, which needs a shortened lead-screw and comes with advice to fit a half-nut depth-adjuster to the design given. It's essentially a screw with a coil-spring threaded onto it.

I am not convinced the extra adjuster made much difference. Engaging the half-nuts on the right number on the dial when screw-cutting is still fraught, though this may be from accumulating wear-errors on my specimen.

.

Baz -

Yes, the apron will drop away but be left hanging on the lead-screw unless you've removed that first! Not a good situation.

My dodge when removing and refitting a lathe saddle is to place blocks of wood under it first, not tightly but just enough to support the assembly so I can remove all the screws in a controlled manner, and vertically.

.

Swarf Mostly -

I think most lathes with a rack-and-pinion feed are arranged with the rack teeth pointing down, and the rack tucked away up under the overhanging shear, for the reason you say.

It usually stays reasonably free of swarf but the fine chips from material like brass can find their way into the oddest corners.

My ML7 came with a spring loaded adjuster screw in the bottom of the lower halfnut as did all others I have seen. It controls the depth of engagement of the two nuts, but not the over all alignment. That has to be done by engaging the halfnuts and observing any flex or movement of the leadscrew and then either adjusting the lead screw mounting brackets, or by shimming the apron to move it downwards, or removing metal from the top face of the apron to move it upwards.

But it still makes no difference to using that tiny Myford thread chaser dial. Thing is so small that it is hard to to get the line in just the right position before closing the halfnuts. My old Drummond has a larger dial made by a previous owner. It is probably 1" diameter or larger and is much much easier to use than the little Myford effort. Making a bigger dial for the Myford is a long standing member of my Round Tuit list.