Thread gears for Warco GH-1322 lathe.

[Tristan LuscombeParticipant @tristanluscombe46103]

Hi Howard,

Sadly the only gears I have with this machine are the 32, 85 and 100 tooth gears that are in situ.

I have used lathes quite extensively, but it was a long time ago and much as my ego rails against it I really consider myself a pretty basic user as a result.

I am always keen to hear recommendations for educational material, so I'll see what I can do about tracking down those books.

Thanks for your comments, this is terrific stuff and will help enormously!

Tristan.

[Tony Pratt 1Participant @tonypratt1]

Posted by not done it yet on 05/05/2022 07:38:09:

Posted by Tony Pratt 1 on 04/05/2022 21:13:17:

3 holders are nowhere near enough.

Tony

You,ve (clearly?) not looked at the Arceuro offerings? Tool post separate, or with 3 tool holders.🙂🙂

The school has a mill. Both gears, and extra tool holders, should not be difficult to make? It’s what I did.

They also sell single tool holders which I have purchased in the past, also bought directly from China & I did make one special holder for a cut knurling tool so I have a fair idea of the options.

Tony

[Howard LewisParticipant @howardlewis46836]

Hi Tristan!

What gears do the manuals say should be with the lathe?

Could Warco, or any of the other importers of the same machine in another guise, be able to supply replacements?

At a push, with a Mill available, together with a Rotary Table, and suitable gear cutters, you could even make your own.

(I halved the feed rate for my lathe by cutting a 80T gear to replace the 40T gear for the input to the gearbox )..

Howard

[John HaineParticipant @johnhaine32865]

Electronic leadscrew?

[DC31kParticipant @dc31k]

Posted by Howard Lewis on 05/05/2022 11:53:15:

Reverting to the original query.

In a very early reply to this thread, Jason posted a link to the manual for the machine. I am quite sure the OP can and will read it. It would be possible to save yourself an enormous amount of wasted typing if you read the same manual. Among other things, asking other people what the manual says would not be required.

As well as full details of the gearbox and change gear settings and physical arrangement, the posted manual contains details of the leadscrew indicator fitted to the machine, from which the pitch of the leadscrew can be calculated. Given also that the lathe is in a school, I do not believe the class will have a great deal of interest in imperial threads.

[JasonBModerator @jasonb]

Indeed!

I'm not sure if this lathe would take to the JS belt and pulleys approach. Metric screwcutting uses 1:1 gearing from the headstock output shaft to the gearbox input shaft. However feed rates are closer to 1:3 ratio.

If you went with 1:1 so you could move seamlessly from feeds to metric screwcutting then all the feeds would be 3 times as fast. Even if you went 1:2 and halved all the metric pitches which would be a reasonable thing to do and I can't see much call for 10mm pitch threading anyway you would still double up the feeds making the finest 0.134mm/rev which is double what I tend to use most of the time.

[DiogenesIIParticipant @diogenesii]

IF it's of any use whatsoever, the current GH600 comes with a 120/127 pair, 1 mod., each slab10mm thick, width of pair 25mm; they are mounted on a 20mm sleeve with 6mm key and the sleeve bore is 14mm. The sleeve appears to be press fitted.

If these would fit the stud (and Warco could supply them) it would only leave you a pair of 42's to find.

Unfortunately the other supplied GH600 gears are 32, 64, and 40.

[JasonBModerator @jasonb]

You could buy a single 42T stock gear from on of the bearing suppliers for not a lot and they are thick enough to get two from if you saw and face them. Could also get the 100 and 127 that way but the bigger gears are a bit more expensive.

Surprised they are 1MOD as my smaller 280 used 1.5MOD

[Tristan LuscombeParticipant @tristanluscombe46103]

Warco have been really helpful and responsive and got back to me concerning the missing bits. Sadly the 120/127T is £200+ on its own and there's no way the department has the budget for that kind of expenditure on a single gear. They also sent me a manual which interestingly looks like a cross between the fairly minimal one available online and the more comprehensive Grizzly one.

I'm interested by the site you linked, JasonB, I wonder if they have suitable gears for all of it? They look far cheaper!

Thanks again, guys!

[DiogenesIIParticipant @diogenesii]

Posted by JasonB on 05/05/2022 19:18:25:

 

.. ..Surprised they are 1MOD as my smaller 280 used 1.5MOD

 

Yes, I was surprised but the 120 is 122mm OD and the 127 is 129mm – I wouldn't be surprised if the 1322 uses bigger.

Edited By DiogenesII on 06/05/2022 11:38:12

[peak4Participant @peak4]

Tristan, regarding the toolpost I mentioned earlier Toolco might have some left, though only a couple, not 4 as shown £108 posted.
I didn't mention it earlier, as I wanted to order one myself.

Re the gears, I'm not sure that the GH600 info will be correct for your lathe, as I think the GH1322/1330 is based on a different bed etc. the large gear also runs on a pair of ball races, not a plain bush
I've just been out to measure the 100/127 from my own GH1330, but don't have a conclusive result for you.
N.B. mine is imperial, and yours seems to be metric, so I don't know whether yours or mine uses DP or MOD, they could even have come from different factories.

100 tooth gear 152.38mm overall outside diameter
127 tooth gear 161mm overall outside diameter

Using this on-line calculator https://www.technobotsonline.com/gear-size-calculator.html

The 100 side comes out as Estimated MOD Size 1.25 Confidence 84% Estimated DP Size 16 Confidence 94%
However
The 127 side comes out as Estimated MOD Size 1.00 Confidence 80% Estimated DP Size 20 Confidence 98%
Obviously this can't be right, so there seems to be a bit of machining tolerance on the OD.

Does the manual/parts book from Warco give the MOD/DP gear size?

FYI, I've also pulled out a few other gears
48 tooth 62.5mm Estimated MOD Size 1.25 Confidence 100% Estimated DP Size 20 Confidence 98%
52 tooth 67.25mm Estimated MOD Size 1.00 Confidence 80% Estimated DP Size 20 Confidence 98%
55 tooth 71.09mm Estimated MOD Size 1.00 Confidence 80% Estimated DP Size 20 Confidence 98%

This would tally as my Myford 55 tooth gear lies very well on top, though slightly larger at 72.38mm, which give 100% confidence @ 20DP, which we know to be correct. They don't mesh very well, which again seems right as the pressure angles will be different. 14.5° on the Myford as against an expected 20° on the Warco

It's looking like my Imperial Warco GH1330 uses 20DP gears It was manufactured Dec 2003.

Maybe measure the gears on your GH1322 and plug them into the same calculator.

N.B. as mentioned earlier in the thread, if you don't need to cut imperial threads, you don't need the 100/127 gear, just something else about that diameter to act as an idler.

Bill

[JasonBModerator @jasonb]

Tristan, can you measure the diameter of one of the gears and it's thickness. The 100T would be the easiest. Then I can link to suitable ones from Belting on line.

But do try the 3D printed route first, ( also need gear sizes for that) there are people here who have used them and others who sell the printed ones on e-bay. They have the added bonus that they will probably fail if a student has a crash rather than something more expensive.

I would not trust that calculator in the post above as 100T at 1.5MOD will be 153mm dia not a 1.25MOD which should be 127,5mm

The calculation is a simple (Number of teeth plus 2) x MOD and the Warco ones tend to be a tad undersize.

 

Edited By JasonB on 06/05/2022 13:07:56

[peak4Participant @peak4]

Posted by JasonB on 06/05/2022 13:01:56:

…………

I would not trust that calculator in the post above as 100T at 1.5MOD will be 153mm dia not a 1.25MOD which should be 127,5mm

The calculation is a simple (Number of teeth plus 2) x MOD and the Warco ones tend to be a tad undersize.

 

Edited By JasonB on 06/05/2022 13:07:56

Jason, I think the calculator is probably fine, but Garbage in-Garbage out

I've absolutely no idea why I typed 100 teeth for the gear, both in my previous post, and into the calculator.
The combined gear is 120/127, so the numbers do roughly work out.

You're most welcome to edit my post, with the correct numbers as below, but I'm beyond the time limit to do it myself; maybe even just change the font to strikethrough

I've just been out to measure the 120/127 from my own GH1330,
120 tooth gear 152.38mm overall outside diameter
127 tooth gear 161mm overall outside diameter

Using this on-line calculator https://www.technobotsonline.com/gear-size-calculator.html

The 120 side comes out as Estimated MOD Size 1.00 Confidence 80%
Estimated DP Size 20 Confidence 98%

The 127 side comes out as Estimated MOD Size 1.00 Confidence 80%
Estimated DP Size 20 Confidence 98%

I'm reasonably happy that my own imperial GH1330 machine is 20DP, but Tristan's may well be MOD.
Apologies to both of you

Must drink more coffee before pressing the Add Posting button; I thought I'd double checked everything, since the results I had seemed odd to me as well.

Bill

Edited By peak4 on 06/05/2022 15:47:50

[Howard LewisParticipant @howardlewis46836]

According to the information in Ivan Law's book "Gears and Gear Cutting", (No 17 in the Workshop Practice Series )

You can find the Module number of your gears by counting the teeth, and measuring the OD. A simple formula will give the Mod number.

(OD in mm ) / (tooth count + 2 ) = Module.

A 1.25 Mod a 120T gear should be (122 x 1.25 ) mm diameter = 152.5 mm

A 1.25 Mod 127T gear should be (129 x 1.25 ) mm diameter = 161.25 mm .

Most probably, such gears can be bought from companies, such as Davall Gears, HPC Gears, Reliance Gears, etc, (At what price, I know not ) and fastened together, to be modified to fit onto your lathe.

Similarly, any other unavailable gears could be sourced from any of the above companies, in a material of your choice.

Unless you can find someone either to make or 3D print them m for you, (being a member of a Model Engineering Club, you may find such a helpful soul!

Howard

[Tristan LuscombeParticipant @tristanluscombe46103]

Morning everyone, thanks for the continued support and brilliant suggestions and ideas. I will definitely get the calipers on those gears when I get a chance, JasonB – sorry, as the exam period is upon us I'm getting less and less time to do real work and more time supporting the staff and preparing paperwork 😀

[Tristan LuscombeParticipant @tristanluscombe46103]

Incidentally, my contortions with calipers (the lathe is almost right up against a wall ) would suggest that the 32T is 42.37mm diameter and 9.8mm thick, the 85T is 108.61mm diameter and 8.5mm thick and the 100T is 127.3mm diameter and 9.9mm thick.

[JasonBModerator @jasonb]

That would seem to suggest 1.25MOD, I'll post some links later

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