JW Stringer model D screwcutting gears

hello i am new to screw cutting i have a JW Stringer model D and i would like to try my hand at screw cutting how. How many gears am i likely to need for a start, the advert says the gears are 14dp with a set of 10, 14, 16 18,20,22,24,26,28,30,and 40 tpi. Do you think i will find any of these gears as the lathe came without them other than that it is in excellent condition and appears to have had little use .Any help would be most gratefully received many thanks DaveC

Hello Dave,

I have just come across your query which seems to have been ignored by everyone else.

I am not familiar with your lathe, nor can I find it in the list on lathes.co.uk so can't comment on the 14 DP gear size suggested, but an indication of centre height would help in deciding if they really need to be of that size. The other piece of information concerns the leadscrew pitch which is an important element in the calculations.

I am unable to attach pictures, tables or anything else to my replies because of a tiresome compatibility issue with my server but I will happily help in creating imperial and metric tables for you by email if you can answer the queries above

Contact me please at:- wood_y(at)btinternet(dot)com all in lower case and no spaces

Regards Brian

Edited By Brian Wood on 13/10/2017 09:26:22

Hello Dave

I am not familiar with the Stringer Model D. However, the EW lathes by Stringer use 16DP changewheels (as stated on Tony Griffith's web site) which I can confirm from personal experience.

Niall

Niall,

Helpful information to track down the maker, thank you. I now know the leadscrew pitch which is 8 tpi

Dave will need the following 16 DP change wheels for the screw pitches he listed. 20t, 25t, 30t, 35t, 40t, 45t, 50t, 55t, 60t and 65t [ ten in all] If he can add a wheel of 63t as well that will allow some metric pitches to be possible.

As suggested earlier Dave, send me an email and I'll provide some gearing tables.

Regards Brian

If you are starting off with no change gear at all, and for a relatively rare lathe, you may be better off to buy a set of new mini-lathe changewheels (the metal ones preferably). You may have to make some mods to the mounting quadrant etc to accommodate the smaller gears.

Hello Dave.

As Brian says the gears are 16 DP, the set of ten also listed by Brian were available when the lathes were made. The list is on lathes.co.uk, but under the name EW. It is worth reading. I assume that your lathe is fitted with back gear as it is the model D. For gears you either use 16 DP gears available from HPC Gears. They are expensive to put it mildly. Or you can use 20 DP Myford gears, much cheaper and available on ebay. A design was put online to use them for fine feed by a contributor also describing updating the lathe. Put 'STRINGER EW LATHE' into Google, look and read.

The leadscrew is 8 TPI, unfortunately it is right handed which makes fine feed impossible using the 16 DP gears. Again a modification was published in ME by J W Constable many years ago using two extra gears.

I am in the process of getting one of my EW lathes running. I found it beyond belief that a lathe designed and built post WW 2 used Whitworth threads throughout. It is a substantial machine, but some design features make you tear your hair out.

I wish you success with your lathe.

Mike Potts.

I know what you mean. My 1960s Willson has BSW fasteners which are obviously more difficult to get than eg metric or UNC. Fortunately, the market for vintage motor bikes seems to have encouraged manufacturers to go on producing BSW.

Dave

I have saved images of the screwcutting table and the original leaflet from various web sources, but as they are not my copyright it is not appropriate to post them. If you wish further information send me a private message.

Niall

Hello again Dave,

Looking at the specification for these lathes, I am even more surprised that change wheels of 16 DP were supplied and when I was replying earlier, I too had considered suggesting [as Mike Potts says] 20 DP Myford change wheels which I am sure would be more than adequate for these small machines, as well as being available and considerably cheaper than trying to find 16 DP gears. Starting from scratch as you are it is quite feasible.

There is another added bonus with using smaller change wheels and that is extending the range of tooth counts to include, if you wish, 70t and 75t. Add in a wheel of 38t and screw threads of 19 tpi become possible.

The standard Myford ML7 pitch charts would apply as well and give you a much more comprehensive capability.

My offer still stands though

Regards Brian

No idea if it would help but there's a guy on homeworkshop.org selling a barrow load of gears. If you are almost completely devoid of gears, it may be a cost effective way to get started. Trying to acquire a decent set of Myford etc gears could cost you an arm and several legs and I doubt you'll find many of the genuine articles.

Murray