Member postings for Richard Hardcastle

If I understand things write The full diameter of a Mod 1 gear is teeth+2 in mm? if that's correct then are these what i need? **LINK**

Thanks Andy and Hopper. I was told the original owner used it to build model jet engines, The table he built for it weighs a bloody ton I can tell you that...I had to take the legs off it so I could move the table top. I think the compound on the tumbler is one piece so i may be buggered unless I can find more Mod1 gears but being new to lathes I have no idea what they would be fitted to as standard or where to look for them. According to the PDF version of the user manual, which assumes the reader has a good knowledge of lathes already, any of the change gears will fit on the mandrel but I'm sure the mandrel is a bigger diameter than my 20dp change gears but I'll check to be sure. If I can swap out the Mod1 gears and forget the tumbler reverse and go direct from mandrel to lead screw via idlers all using the 20dp change gears that'll allow me to cut threads. Then I'll put the Mod1 gears back on so I can use the tumbler reverse and also benefit from the very slow feed rate...does that sound feasible?

In the mean time I'll try and find out where I can get hold of more Mod1 gears so I an build up a selection so I don't have the mammoth swap out each time I have a thread to cut.

Here are the photos of the reverse tumblers . I think my quadrant may be different as well as in other photos of peoples ML lathes they have a quadrant with 2 slots arranged in a sort of V where as mine just has the single slot. I don't know if that will matter but there are plenty on ebay if I need the V type.

The black handle selects forward, reverse or not engaged, the red handle just tightens the v belt.

So it's homemade...that'll be why I've never been able to find anything similar on google lol. I'll have a look tomorrow to see if there's anything that might bolt to it but as far as I can remember the lathe came with a 3 jaw and 4 jaw self centreing chucks, a 4 jaw independant chuck and a 6-7 inch back plate but I'll make sure there isn't anything else I've overlooked.

Evening John and Hopper, the plot does indeed thicken as I've just been in the garage for a closer look at the tumbler reverse and it turns out that all the gears currently fitted to the lathe are Mod1. I've taken the little compound gear off the tumbler to compare it to the standard 20dp change gears and the difference is so obvious I'm surprised I hadn't noticed before. Also that grey 50t gear i just bought of a certain Myford seller on eBay looks a bit p1ssed to me lol

I'll go back into the garage and get you that pic of the tumbler reverse set up you asked for.

Hi.

When I bought my lathe a few months ago it came with various odds and sods most of which were easily identified. However there is what I think is a milling attachment but it looks incomplete. Can anybody tell me what is missing from it please. If it matters the lathe is an ML2.

Edited By Richard Hardcastle on 25/05/2016 14:04:54

Edited By Richard Hardcastle on 25/05/2016 14:07:34

Edited By Richard Hardcastle on 25/05/2016 14:08:21

Thanks to everybody for your help so far. I'll see if I can get hold of the books you mention as there is so much for me to learn and I really do have to get my head around gear ratios especially compound gear ratios so that I can "feel" if the ratios suggested by software seem right.

Martin I've book marked the discussion your link points to as it is quite helpful.

Hopper I will keep the Mod1 gears as the feed rate they produce is very slow which is ideal for me as it keeps things happening slowly and also takes some of the strain off the lathe if I try to take too big a cut. If I'm right you are saying that all the gears from the mandrel to the inner gear of the compound on the reverse tumbler will be 20dp and then the outer gear is Mod1 to mesh with the rest of the gear train which is also Mod1?

If that is so then to set up a 20t-50t (my new 50t arrived this morning) to cut a 20tpi thread I'd swap the outer Mod1 gear of the reverse tumbler compound for a 20t 20dp gear and fit the 50t 20dp to the lead screw and fit suitable 20dp idlers between them?

I also like your comment about being able to mix and match the 20dp and Mod1 gears provided I always have them meshed like for like, so the switch would take place on a compound gear. For instance no harm would be done by leaving the Mod1 outer gear on the reverse tumbler output compound which could drive a Mod1 compound which in turn could mesh with a Mod1 gear locked to a 20dp gear to form the 2nd compound which in turn could mesh to a 20dp on the lead screw...I think lol.

I will put the gears back in their original positions and make some bushes so I can fit the 20dp gears onto the studs for the Mod1 gears...it'll give me a little practice

Thanks for all the info I'll have a look through the forum an see what I can dig up. I have nthreadp which is stating;

Driven gears 25 40 Driver gears 20 20 TPI 20 error % 0
Driven gears 25 60 Driver gears 20 30 TPI 20 error % 0

So I think that's a 20t on the mandrel driving a 25t on a compound locked to a 20t which drives a 40t on the leadscrew.

Yep I can see how that will work for single gears per spindle as they are just passing the drive onto the next gear a tooth at a time. So to have the lead screw turning in the correct direction I'll need to use 2 idlers...unless I can still use the tumbler reverse after changing the mandrel gear?

So if I have a 20t on the mandrel, a 50t on the lead screw and the lead screw is 1/8" per revolution and I want to cut a 20tpi thread the sum is 20(turns of mandrel) x 20(teeth) / 50(teeth) / 8(turns of lead screw) = 1(inch travelled along work peace)? Or is that all wrong lol?

Edited By Richard Hardcastle on 24/05/2016 18:42:41

The original owner of the lathe was an engineer and it was his personal lathe that he had at home so he could have altered things I guess. Apparently he used it for making model jet engines. I've checked a few of the gears and they seem to be 20DP....what does 20DP actually stand for lol???

Yep the gears are drilled for pins...2 different diameters for some reason. I think the mandrel gear is currently a 25t or a 30T but I'm not sure in the tumbler reverse will still engage properly, I'll have to check that. When you say "almost definitely need a sleeve" do you mean for the 1st and 2nd stud so they will accept the changegears?

Hi.

I'm wanting to start practicing cutting threads on my ML. I have most of the change gears, 1 x 15t on a shaft???, 2 x 20t, 1 x 25t, 1 x 30t, 1 x 35t, 1 x 40t, 1 x 45t, 0 x 50t, 2 x 55t, 1 x 60t, 5 x 65t and one collar. I'm certain I have a 50t as well but I can;t find it and it's one of the gears I need for a 20UNF thread

Anyway the little chart in my garage says I need a 20t on the mandrel and 50t on the leadscrew and idlers on the 1st (upper?) and 2nd (lower?) studs. When I take the gears of the leadscrew and try and fit a 50t (must have been a 55t) the lower idler can't reach it as it's a compound gear and the larger of the 2 gears prevents the smaller one engaging with the 50t on the leadscrew.

So I'm wondering just what the idler gears should be. I recently bought the lathe of a chap who didn't really seem to know much about lathes so couldn't give much . On the upper rearmost stud (1st stud?) there's a single peace compound gear with MOD1-100 written on it.

On the lower stud(2nd stud?) is another compound gear with MOD1-80 written on it.

And on the leadscrew is a single gear with MOD1-80 written on it.

This is how they are arranged,

Also the diameter of te 1st and 2nd studs are much smaller than the holes in my change gears is there supposed to be some sort of bush I should have?

Here are my change gears.

If somebody could help me understand what gears I need and where/how to fit them I would be very grateful as I have been brought to an abrupt stop with my little project

Many thanks

Rich