drummond pre b type

Unless you are thinking about doing production runs I wouldn't worry about DP stuff, you won't live long enough for it to be an issue

The bit you need to watch for if you're getting changewheels is the centre hole size/shape, whether there is any keyway slot, and whether there are any pins

The pins you can fit/remove easily, the keyway is harder to replicate but do-able with a file, the wrong holesize is the biggest pain of all to correct

Hi
On my Drummond flat bed lathe I added another arm so I could fit another set of gears to have a slower feed . These are the pin type gears .The lead screw is 8 tpi
Nobby

The concensus of opinion on the Yahoo Drummond lathe group **LINK** is that ALL Drummond lathes use the same change wheels regardless of what the lead screw pitch is. The only thing that the leadscrew pitch alters is what wheels you need to set up in order to cut a specific screw thread. The spec for the change wheels is 5/8in bore, 14dp with a 14.5 degree pressure angle (pa). Drive to the gears is by 2 pins that locate in holes in the hub - no keyway, the bore is plain. The gears appear regularly on E-Bay. On the Yahoo group there is a files section,where you'll find a list of the "normal" Drummond lathes with the change wheels that were supplied or recommended for that particular model.

Well worth signing up to the group for the information, help and advice that the members can offer. By and large the folk on there are not lathe "polishers" but expect their machines to be fully functional and working machines.

Be aware that there are some changewheels in the wild that whilst strongly resembling the "normal" Drummond / Myford ones, don't actually fit.

The part set I had off E-Bay had variable centre bores and slightly different pin positions from the ones on my M Type. The tooth numbers were cast in, so that may be a warning sign.

The red painted one is the E-Bay purchase, the green one a postwar Myford. The pin position is sufficiently different to prevent them sitting together on the spindle. They can (hopefully!) be bodged.

Eug

Edited By Eugene Molloy on 03/11/2014 10:29:52

Hi - I'd have thought that you should have the holes in the gears as it suggests that without you're relying on friction to hold the gears in place on the various shafts and they'll have a tendency to slip and loose synch. The pins will be pretty much essential in the gears that are compounded on the studs as well. Looking at the photos on the lathes.co.uk website for the "pre B" flatbed all the change wheels have the pin holes. Somewhere in the files on the Yahoo Drummond group I think you'll find the spec for the pin spacing as well as the hole size. From memory the pins are 3/16 in. imperial taper pins (1;48 taper) and can be slightly problematical to get hold of as you only need a handful and most places will try and sell a box of 100 (or more). Metric taper pins theoretically have the wrong taper (1:50) but a bit of emery or a file applied in the lathe would soon correct that. The taper is only used to secure the pin in the gear (one pin per gear) and the bit that projects is a loose fit in the clear hole in the shaft collar or hole in the adjacent gear. If your wheels are not drilled for pins then you could drill them parallel rather than tapered (taper pin reamers are available) and use parallel rod to make the pins. The pins could then be fixed by one of the weaker Loctite type assembly compounds or slight deformation of the pin end to get it to grip. You're only stopping the pin dropping out, not putting any load on the fixing. The big thing to be aware of - and it might apply to your gears if they don't seem to have holes is that the pins can get broken off in the gear. You need to look very carefully then to see which is the larger end of the broken pin before you try and drive the stump- end out. Trying to force the large end out through a tapering hole is likely to result in a broken gear as they are cast iron and the pin holes are quite close to the gear bore.

Hi Nobby I have the same arm as you . I only needed a short arm . My gears have pins in too I post pictures set up with my reverse tumbler fitted.

Cheers blackcat hope your gears worked.