Boxford goes crunch! Now refuses to turn.

After the great advice I got on here earlier regarding feeds on my Boxford, I decided to give it a try. Everything was going well, I was just taking tiny cuts and using plenty of fluid. I increased the size of cut, marginally (we really are talking small cuts here, less than 0.5mm off the diameter, as I'm trying to get a feel for the machine). Then she started to labour a bit and all of a sudden made a horrible crunching noise so I stopped everything.

Apart from a minor stiff spot in the gear train, I could detect no real problems there so I tried starting up again with the leadscrew disengaged but the same noise happened. I've traced the problem to inside the headstock casing, there's a sliding gear to put the main drive in neutral before you engage the backgear, this locates the belt pulley with two pins that fit into holes on the face of the gear. I've looked at this part before and thought the pins didn't go into the holes very far but just assumed that was the design. Now it seems my fears may have been right.

Sorry for my lack of the proper terminology for these parts but what can I do to get my lathe turning again?

Do I need new drive pins? Or does something need adjusting?

It is always difficult to diagnose such problem with a (necessarily) vague description, so bear with us.

Could it be that the pins you describe are there to lock the back-gear (low ratio) to the drive pulley, and normal drive (high ratio) requires the pins to be disengaged? I am not familiar exactly with the Boxford gearing but this is a common arrangement. So, could your 'sliding gear' be moving so that both ratios are engaged at the same time?

In a car or motorcycle gearbox there are interlinks to prevent two gears at once, but in my experience a lathe is not such a foolproof design. Have a good look anyway and report on what you find. It may be that there is a catch or linkage which is not there or not properly adjusted.

And I hope that an actual Boxford owner is getting over his mince-pie-fest and reading your query soon.

Regards, Tim

No, it's the other way around on this one, if you leave it engaged and engage the backgear at the same time, it locks the spindle (although I've been warned not to use this for tightening chucks etc).

To anyone familiar with a Mk1 Boxford, this would be easily understandable (I hope), even with my dreadful explanation.

I've asked the question in the Yahoo group as well. The more I use this machine, the more I think it needs a thorough strip and clean. I'd do the same with any stationary engine I bought but I'm not so sure about putting a lathe back together.

Some pictures (hopefully). Sliding gear engaged, disengaged and the control knob.

Edited By Ian Rees 1 on 30/12/2015 17:56:46

There are two levers used to engage the backgear on the Boxford. One is on the front or top depending on model and slides the big Bull gear off the pins that link it to the pulley block. Doing so allows the spindle to rotate free of the pulley and so in 'neutral' as you say., It may be that the lever for this is loose on the shaft so it has slid out of full contact. The way the bull gear is moved is by having a groove in it rather like a pulley in which a bronze shoe runs linked to the operating lever. As this gets no lubrication as it is difficult to get at over 50 years it will have worn. A LOT. This would allow the gear and pulley to drift apart and just be on the ends of the pins.

The other lever is on the left side rear of the headstock and moves the layshaft back an forward. It will lock the spindle if it is brought forward when the bull wheel is still engaged t other pulley. DO NOT use this as a way of locking the spindle. DO NOT allow this lever to move while still running.

Ok now see your pictures.. Your pins are unusually short. Are they loose? The engaged position is not looking very close to the pulley, it should be right up against it, so I think it is a worn shoe.

This diagram and parts list might help clarify.

**LINK**

MichaelG.

I was wondering if I could adjust the eccentric bit on the lever to make the pins and gear engage a bit better but it's looking more and more like this machine needs some proper attention, rather than a lot of quick fixes.

Thanks for the replies, Bazyle, you're spot on, again.

check that the pullys are inline with the holes in the gear,somtimes the pully will slip round if you have crashed so you will find that the pin is slightly out of line and you strugle to get it in this has happend to me there is a grubscrew in the pully slacken this then slide lever over and keep moving the puly until the pin pops in the hole of the gear then lock the pully.Kevin.

Oil on gears is less likely to form a grinding paste than grease on gears. Is there a Boxford recommended lubricant for these gears?

Martin

A lubricant I have found useful for such jobs is spray (aerosol) chain lube. This is a sticky product which goes on very thin and can penetrate well; when the solvent evaporates the residue is more a sticky grease than an oil. Ideal for leaf springs, brake cables, ball joints, etc, as well as (obviously) roller chains.

Cheers, Tim

Edited By Tim Stevens on 31/12/2015 11:08:31

Edited By Ian Rees 1 on 31/12/2015 12:38:07

Hi, I agree with Tim, chain & cable lubricant is good, sticks like .... to the proverbial blanket.

Regards Nick.

P.S. Don't use it in bearings though.

Edited By Nicholas Farr on 31/12/2015 13:07:10

Shame you haven't got a lathe - you could turn up some new drive pins...

:-0

Sorry...

Neil

I have some parts from a CUD and had a look at the headstock and the pins that disengage to allow back gear to be engaged look long than the ones in the picture probably closer to 3/8" sticking out. My AUD does not have the same arrangement as it is a later machine and the pins are spring loaded and only one lever on top.

Ian, you have a PM