Tumbler reverse gears HELP

[bazmak]

Hi everybody,i have just purchased an Advance Lathe on Ebay and i am in the process of stripping down,refurb and build up.Does anyone have one of these lathes ? Mine is a very early model with no tumbler reverse gears.I would like to make and fit the TR gear assembly.Can anybody give me the basic setout dims
and gear sizes/centres to give me a start.I have min no of gears which are the myford type.I can purchase more or replace completely with the sieg gears.
I need to design and build this assy.The basic setout and dims would give me a good start.Any photos would also be helpful Regards Barry

 

[bazmak]

Many years since i was involved with spur gears,apart from DP and no of teeth what is the main difference between
myford and sieg change gears as an ordering ref.Please help an old fool Regards barry

 

[joegib]

Not sure whether you've seen this but Tony Griffiths at Lathes.uk has a write-up covering Advance Lathes here:

http://www.lathes.co.uk/advance/

Per the article early models were a bit crude but later ones were decent machines. He suggests that tumbler gearing was not standard equipment but an add-on. As you'll see, there are quite a few pictures, some showing the tumbler gearing set-up. There's one nicely maintained/restored machine so if our Australian members can't help directly it might be worth asking Tony to forward your queries to whoever submitted the photos of that machine to his archive.

Not sure I understand you query about the order ref. Myford gears are 20DP 14.5 degrees pressure angle. Don't know about Sieg ones though.

Joe

 

[bazmak]

thanks for your reply joegib,my memory told me that DP was diametrical pitch
the dia mid point on the teeth,which therefor increased with the no of teeth
Further to revision with my aged brain i now see that Myford gears are 20DP
14.5PA.Fairly std and the DP is fixed and does not relate to gear dia.The sieg
gears appear to be oddballs so i will stick with myford which can be adapted
to suit the advance.Will have a look at your website and keep in touch
I know the t,gears were an addon with later models hence my attempt tto build the assy.Regards barry

 

[tjwal]

Without looking it up I'm trusting my memory! DP is defined as the number of teeth on a 1" diameter gear, where the diameter is measured at the midpoint of the gear. The Seig uses a metric gear, most likely Mod1 which is defined differently. IIRC Mod1 would be equivalent to a DP of 25.4. If you can get them stick with the Myford gears. Gear spacing is based on the Pitch diameter which in your case will be # of teeth divided by 20.

 

[bazmak]

Thank you tjwal for your input.Definition of DP now makes sense.I had already made the decision of sticking
with myford gears.Now i have to aquire some.Can anybody in Oz help

 

[tjwal]

Rdgtools in the UK sells myford gears for about $20 each including VAT. I'm in Canada and have found their shipping pretty reasonable, I don't know about Oz though.

 

[bazmak]

I have ordered additional gears from Uk will keep you posted on the tumbler reverse

 

[bazmak]

Gears arrived and made the tumbler reverse,bit of headscratching
but finally got everything made and working Still a few tweeks to do
Im getting more fun out of this than i ever did with making a steam loco
I suppose its because the results happen a lot quicker
I have received some additional gears for the sieg from US
thanks for your input Tin.Now to do some screwcutting on sieg
so i can make adaptor plt and fit sieg chucks to Advance

 

[tjwal]

Very nice job on the headstock cover! I looked up the Advance on lathes.uk the show a countershaft. Unless you have a slow speed motor you might be spinning running the spindle too fast.

 

[bazmak]

Hi Tjwal,this was the very early very basic model.No t,rev no cshaft etc.Has backgears
havent really run very much.Need more gears,feed still too coarse.Only have the 4 jaw
and i had to machine new jaw screws from 1/2W capheads.I want to make adaptor plate next
so i can fit sieg chucks etc.Im not in a rush to make chips yet.Need starter switch.Running on
extension lead at moment,not ideal.Lathe had broken/missing parts only bought it as a project
I impressed with it for size and quality.Have seen the later models wit c'shaft etc for $600
this cost me $300.Bought it for fun not profit.Will keep this thread going. Bazmak