Denford 280 Synchro lathe

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rpwilson
CNC Expert
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Posts: 155
Joined: Tue 03 Jun , 2014 15:20 pm
Hardware/Software: None. I own a pre CNC Denford 280 Synchro lathe.

Denford 280 Synchro lathe

Post by rpwilson » Wed 04 Jun , 2014 15:26 pm

Having recently bought a 280 Synchro, c1980, the model with the manual speed change lever. I thought I'd better take the top off the headstock and make sure everything was OK inside.
Its spotlessly clean, the oil is so clear I can see the bottom of the casting through it, and the gears are all in good order. The only thing which surprised me (apart from how clean it was) is that the toothed belt runs in the oil. Is this normal or is the oil level too high? I was thinking of changing the oil in the headstock, along with the gearbox and apron , because I don't know how old the oil is, but haven't yet spotted the headstock drain plug.

Richard

Pete.
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Location: Kent, U.K.

Re: Denford 280 Synchro lathe

Post by Pete. » Wed 04 Jun , 2014 18:57 pm

Yes the belt runs in oil, I use ISO32 hydraulic oil. You'll notice there's a thin toothed wheel in there too which seems to do nothing. On your lathe it does in fact do nothing - it's a trigger wheel for the speed readout on the electric-speed-control model.
Take care when changing the high-low speed range. Either stop the spindle and jiggle the chuck to engage the gears or let it run down to almost stopped and gently move the lever in. Doing it at any sort of speed will trash the plastic gear in short order. Also you might find that the headstock gets noisy when hot and the high-low gear lever is hard to shift. This is because the clearance on the plastic gear is too little, there was a revision on the drawing to increase the clearance. The only cure is to make a new gear.

I can't recall a drain plug. I think I mopped the oil out of mine with rags and paper towels.

rpwilson
CNC Expert
CNC Expert
Posts: 155
Joined: Tue 03 Jun , 2014 15:20 pm
Hardware/Software: None. I own a pre CNC Denford 280 Synchro lathe.

Re: Denford 280 Synchro lathe

Post by rpwilson » Wed 04 Jun , 2014 21:34 pm

Pete. wrote:Yes the belt runs in oil, I use ISO32 hydraulic oil. You'll notice there's a thin toothed wheel in there too which seems to do nothing. On your lathe it does in fact do nothing - it's a trigger wheel for the speed readout on the electric-speed-control model.
Take care when changing the high-low speed range. Either stop the spindle and jiggle the chuck to engage the gears or let it run down to almost stopped and gently move the lever in. Doing it at any sort of speed will trash the plastic gear in short order. Also you might find that the headstock gets noisy when hot and the high-low gear lever is hard to shift. This is because the clearance on the plastic gear is too little, there was a revision on the drawing to increase the clearance. The only cure is to make a new gear.

I can't recall a drain plug. I think I mopped the oil out of mine with rags and paper towels.
Yes, my enquiries regarding oil had led me towards ISO32 hydraulic oil. I don't suppose you know when the drawing revision to increase the clearance was, do you? Mines No. 28658, which I'm guessing was made 1979/80, because theres a photo of one on the www.lathes.co.uk site which is 30393, with a date stamped on the plate of April 1982. I've always made a practice of only changing hi/lo with the machine stopped, probably because everything I've owned before needed a pin engaging or disengaging, so I hope I can keep the gears in their present condition.
I've seen that thin toothed wheel in photos, but it doesn't seem to be there on mine. Just 2 identical slotted collars behind the front roller bearings for adjusting the preload.

Richard

Pete.
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Location: Kent, U.K.

Re: Denford 280 Synchro lathe

Post by Pete. » Wed 04 Jun , 2014 23:16 pm

The drawing is BVS100-105, as attached.
Attachments
BVS100-105.pdf
(742.5 KiB) Downloaded 704 times

rpwilson
CNC Expert
CNC Expert
Posts: 155
Joined: Tue 03 Jun , 2014 15:20 pm
Hardware/Software: None. I own a pre CNC Denford 280 Synchro lathe.

Re: Denford 280 Synchro lathe

Post by rpwilson » Thu 05 Jun , 2014 0:40 am

Pete. wrote:The drawing is BVS100-105, as attached.
Thanks, that's really useful. At least if I do mash a gear, I've got the drawing now to make a new one!
The mod seems to have been done in late 1978, so if I'm right about the build date of mine being 1979/80, then its already got the modified gears in it.

Regards
Richard

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