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Starting to build fast speed gear for Drummaond Lathe Rebuild

Lathe Rebuild Drummond

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Nicholas Farr16/02/2017 23:03:59
1624 forum posts
831 photos
Posted by Neil Wyatt on 16/02/2017 14:20:49:
Posted by Martin Newbold on 15/02/2017 16:11:07:

Well I had to buy new angle as the B&Q angle iron lol now mild steel was not regular or a right angle inside and out.

B&Q angle iron is perfectly good as angle iron. Rolled angle iron isn't a precision product, up to 100mm leg length it can be up to 1mm out of square either way.

Hi, and it very often is.

Regards Nick.

Neil Wyatt17/02/2017 09:25:30
13075 forum posts
567 photos
67 articles

Yes but angle iron is really just a structural product meant for things like keeping up garage roofs and intended to be used with similar tolerances as wood or concrete.

Just because WE use it for other things doesn't mean we can expect it to be to the same standard as bright drawn bar, for example. If we need more accuracy, we need to cough up the extra for bright drawn angle.

Martin Newbold17/02/2017 14:10:50
372 forum posts
214 photos

Lol the profile was not good at all but ok for simple jobs have fabricated out of proper right angle and have it working in rough mock up pending new rod. The B&Q steel not iron was thicker at ends and narrow in centre the items I had was not right angles inside or out. Perhaps they have changed this and thier new stock is different. I did not go back but brought else where.

Two welded up

First mock up

first weld up try

Martin Newbold17/02/2017 16:59:19
372 forum posts
214 photos

Had not cleaned up welding so the seatings were not seated properly forcing an odd angle . Much better now they have been cleaned up . My maths has been thus

n1 = 1600rpm, d1 (Drive)=25mm, d2 (Pulley drive )=130mm d3= 100mm d4 (on lathe ) =130mm

n4=(n1 *d1*d3)/(d2 * d4)

n4 = (1600 x 25 x 130)/(100 x130)

n4 = 400rpm

I just need a longer 3/4 silver steel bar around 12" long as he width is wider than my original pulley bar

Edited By Martin Newbold on 17/02/2017 16:59:37

Martin Newbold17/02/2017 19:14:24
372 forum posts
214 photos


Well have decided it might be time to take the electrics of the top of the motor I have and retro fit on on the bench . I have seen dewhurst and many other reversing levers on ebay but know in my box the switch is a very complicated beastie even though its single phase with a big cap its kitty motor I think would it be difficult to convert this to a dewhurst or similar switch what is involved can anyone give any suggestions please?.


Thanks M

Edited By Martin Newbold on 17/02/2017 19:21:18

Martin Newbold17/02/2017 20:23:37
372 forum posts
214 photos

I presume something like this would work

Ian S C18/02/2017 09:27:36
6698 forum posts
219 photos

Why do you need silver steel for the counter shaft, BMS will be good here.

Ian S C

Martin Newbold18/02/2017 13:34:28
372 forum posts
214 photos

Hi Ian , I could not find any just 303 Stainless so have gone for that . Did not say what it was made of so hopes it is 3/4 and not nearly 3/4. Am really hoping this is all going to work as not going to import a switch until i get somewhere with speed . Will need to figure it out though most likely need to move the motor control else where as its in way

Thanks M

Martin Newbold18/02/2017 19:01:01
372 forum posts
214 photos

welded in nut holderWelded in nut holder one side

Martin Newbold18/02/2017 19:01:49
372 forum posts
214 photos

Hashed up my maths kitty motor runs 3000 rpm lol

Martin Newbold18/02/2017 19:19:02
372 forum posts
214 photos

Added in the eye bold and nut all fits ok on this one . Checked my excel spreadsheet and 3000rpm gives me extra 59rpm. I can fit in a six in pulley or even an eight so have room to change speeds MAdded the eye bolt and going to cut down a nyloc to fit in to bearing

Nicholas Farr19/02/2017 07:35:31
1624 forum posts
831 photos

Hi Martin, you will be better to put an ordinary std. nut in the bearing aperture and then drill and pin it through the threaded rod, rather the a Nyloc one.

Regards Nick.

Martin Newbold19/02/2017 12:05:02
372 forum posts
214 photos

Hi Nick,

Am going to try the nyloc cut down first. 5mm from the other side of nyloc . I think it should hold fast as it will spin in hole. Why do you think this would not hold i would prefer a castleated nut but its hard to find one 3/4.

still awaiting shaft

Ady119/02/2017 12:30:35
3112 forum posts
414 photos

A note on solid very high speed bushes, something I noticed on an Abu 7000 I have from the 1970s

The outside edge of the bush was convex, so it was like a section of ball bearing with a hole drilled through it and this means the bush can move minutely in its seating during the cast which has a lot of loading and goes up to over 20,000 rpm during a big chuck

Martin Newbold19/02/2017 13:47:10
372 forum posts
214 photos

lol this is only going to run around 450 lol


Nicholas Farr20/02/2017 22:24:55
1624 forum posts
831 photos

Hi Martin, a nyloc may well hold OK, but it will be more of a pain to hold while you are tightening it up, or taking it off if you need too, as you will not be able to get a spanner on to it. A plain nut should screw on far enough with your figures and a roll pin will be both much easier to put in and remove. It's the most common way I've seen it done in industry and far easier that a castleated nut. A small nut and bolt can be used instead of a roll pin if you wish, as long as it is not too long to turn in the aperture.

Regards Nick.

JasonB21/02/2017 07:26:48
12342 forum posts
1096 photos

Or you could dig the nylon ring out of the Nyloc nuts you already have, put a wide sawcut across the top and you then have a castellated nut that will screw on easily and can be retained with a split pin that will wrap nicely around the reduced dia of the nyloc.

Martin Newbold21/02/2017 11:24:23
372 forum posts
214 photos

Thanks everyone I cut the nylocs of with a friends lathe and drilled one and have it pinned with a roll pin works great . Have had to order some more roll pins as I ran out so am in limbo with motor apart until I can fathom what all these connections are fore. I have a circuit diagram but its not helpful as its has 9 types of motors a D.C Series , D.C Compound, Split Phase, Induction Repulsion - Four Motor leads windings in series D.C Shunt , Induction Repulsion Three motor Leads, Three Phase, Two Phase -Three wire , Two Phase - Four wire.

Mine is a Kity motor single phase with a cap and four wires and two temp I don't think it fits into any of these nine so am a little confussed as to what type is what.

Made up nuts for roll pins


Martin Newbold21/02/2017 14:08:53
372 forum posts
214 photos

my connections to old switch are as follows if this helps . I really need and electrical genius

my switch had on it these wires connected to the switch I do not understand the letters b, U, V,W do they mean anything to anyone?

Connector Wires

b Brown(temp)

U Brown(temp) + Red (M) + Light-blue (M)

V Black (M) + Dark-blue( Capacitor)

W Yellow (M) + Brown (Capacitor)

wiring box

Martin Newbold21/02/2017 15:49:04
372 forum posts
214 photos

This is the info on the rotary drum site they wanted 70$US to ship here its a shame its not a Chinese part with free postage that is as good quality makes the purchase around £135 . Anyway I need to figure out wiring for this or Dewhurst his is what they had with it:



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