Warco gh1440 / Chester challenger change gear sizes

[Richard CoxParticipant @richardcox82602]

[Richard CoxParticipant @richardcox82602]

Evening all,

i have a warco gh1440 lathe Same as Chester challenger that only came with certain change gears, does anyone know what should of came with the machine to cover metric and tpi threads and whether the gears are mod or dp,

Rich

[JasonBModerator @jasonb]

You should be able to measure the gear's OD and count the teeth then work out if they are MOD or DP, My money is on MOD probably 1.5

Look at the gear chart printed on the lathe or in the manual and note all the teeth and that will give you what was likely to be included, if same tooth number appears twice on one gear train they you would have got two of those.

[Richard CoxParticipant @richardcox82602]

Posted by JasonB on 14/12/2021 20:33:32:

You should be able to measure the gear's OD and count the teeth then work out if they are MOD or DP, My money is on MOD probably 1.5

Look at the gear chart printed on the lathe or in the manual and note all the teeth and that will give you what was likely to be included, if same tooth number appears twice on one gear train they you would have got two of those.

Thanks for response Jason,

i suspected in the past it was a mod 1.25 as I used a Myford 30 tooth gear to get out of trouble in the past which is very close to the 1.25 mod 20dp I think,

i have just measured the 24 tooth gear across and it came out at 32.50 using a calculator comes out at 1.25 but is close to the dp everything else is metric on the lathe so you would like to think the change gears were also

Rich

[John HaineParticipant @johnhaine32865]

The other important parameter is pressure angle. Myford gears are 14.5 degrees but 20 degrees is more common today I think.

[Howard LewisParticipant @howardlewis46836]

The 1440 will almost certainly use Module gears with a 20 degree pressure angle.

My BL12-24 (Warco BH600 / Chester Crafdtsman lookalike) does, 1.25 Module.! Having a Norton box, it only has two changewheels (40T and 32T ) to cover a wide range of Metric pitches, For Imperial mthreads, it only uses the 40T on the input tom the Norton box.

You can find the Module number for the gears by counting the number of teeth on a gear and measuring the OD in mm.

Module = (Tooth count +2 ) / OD

So a 1.25 Mod gear with 60 teeth would have an OD of 77.5 mm

The GH1440 is a current lathe so Warco or Chester should be able to tell you what changewheels should be with the lathe.

Although, being a geared head machine,according to what you see on Google there may not be any need for them, or if there are, they will be few.. There was a comment saying "No need to faff about with changewheels"

Take a look at Hobby Machinist.

There is information to be found if you look in the right place.

Howard

[JasonBModerator @jasonb]

A quick look on the net produced a good photo (Click it and it enlarges) of the front of the Challenger and it looks like you just need the 120/127 combo plus 60T, 30T and 24T with the gearbox doing the rest for metric. Imperial needs a few more as shown along the top of the left hand chart.

Chances of it being 20DP are slim, go with the MOD1.25. You should be able to get quite reasonably priced ones of these from the like sof Beltingonline

Edited By JasonB on 15/12/2021 07:05:59

[Richard CoxParticipant @richardcox82602]

Thanks for the replies

Rich

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