Lanz tractor

Hi all l seem to be going round an round over what gear cutter size to use for making the gears for the model lanz tractor by jam de waal to me the drawings are not clear what gear set to use ie module 1 or ?,and l do not want to buy a set of cutters that will not do the job ,or do l do as a model maker said just use a single point fly cutter to make them ,so is there a member out there that has made them and could help out here please.

Email the originator? E-MAIL: [email protected].

Actually doesn’t look too important. Multiple gear reductions use larger teeth on slower moving shafts (need to transmit more torque), but that does not look like an issue with this?

Diameter and tooth count are the usual requirements to calculate the MOD. Are these not supplied on the drawings?

Thanks for that , its a bit clearer now ,l think most of the gears can be cut with module 1 cutter and the odd size gears think l will have to fly cut example gear being dia 78.5 x 57 that l work out to be 1.6 module ? or do l get a cheap 1.5 cutter for that.

You may want to have a look at another JDW Lanz tractor build, this one over on HMEM and maybe compare notes.
https://www.homemodelenginemachinist.com/threads/lanz-tractor.31327/#post-325989

Dave
The Emerald Isle

Outside diameter divided by (tooth count + two). = MOD

So, 78.5/(57+2) = 1.33

Centre-to-centre of the gears must be correct, too - and every different tooth-count gear of any particular MOD will have a different diameter....

Phwwwwwwwww gears well a member on the HMEM mailed me ,he used a mix of module 1 an module 1.25 cutters ,as he said 78.5 / 57+2 = 1.33 like not done it yet said ,but theres not a module of that ,so just went to the 1.25 and it worked out ok , so l think will get some cheaper import cutters to keep the cost down and go for it,and hope it works out

Looking at the PDF I have, the gears are 1 MOD. However I have noticed one gear has the wrong outside diameter.

Regards

Gray,

Gray the pdf is what l am working from,what gear size do you think is wrong,but if the gears are all indeed module1 then l will be very happy ,l am new to this so am glad of the help

john

Hi all many thanks for all your help you have been very kind,l will now place an order for a full set of module 1 gear cutters, will have to go for a cheaper set of imported ones but as long as they get this project done ,will be happy ,l am just waiting for gray to let me know what gear has the wrong diameter can then make the blanks.

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Logic would suggest that it must be the 57 tooth

If

D/(57+2) = 1

D should be 59 not 78.5

MichaelG.

The large 57T gear on the diff and the gerbox output are a different size to the other Mod1 gears, as said about 1.33MOD. Probably best to start with the PCD and see what you can get to fit.

If you think that is bad take a look at the ones for teh Robey cane crusher that are being published at the moment, all odd gear sizes

Thanks, Jason ... I haven't looked at the drawings

Was just applying simple deductive logic to Gray's statement

MichaelG.

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Edit: It looks like a diameter of around 74.5mm should be right 

Module 1.25 or 20 DP according to taste

Edited By Michael Gilligan on 12/07/2019 08:15:42

So PCD of the two gears is 101.90mm or 4.012"

If you went with 20DP and use 22:58T that would give you a PCD of 4.000". Add a bit of fiddling with depth of cut and you could get away with that if you don't fancy making a cutter to the tooth profile shown in the detail

Just applying simple practical experience

EDIT, as the Gearbox is mounted on slotted holes you don't have to be too worried about exact PCD so if you want to stick with cheap MOD cutters than 1.25MOD and a ratio of say 22:59 would give 101.25 so the 0.65mm difference is easily taken up by sliding the gearbox

PS do check my hurried maths as I'm meant to be off out working.

Edited By JasonB on 12/07/2019 08:17:00

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Having not seen the drawing, I wouldn't know the tooth count of the matching gear ...

Nice that we reached a similar conclusion though

MichaelG.

Ok trying to take all this in, will make bull gear blank 74.5 diameter and get a cheap 1.25 mod cutter that cuts 55 to 134 just for that gear and module 1 gear set for the rest ,and will play around with the bull gear till it fits alright, off to hide in a dark room now but thanks for the help.

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Whilst you are there, John ... have a play with this calculator: **LINK**

https://www.technobotsonline.com/gear-size-calculator.html

MichaelG.

Hi John,

The gear I looked at quickly yesterday morning which for 1 Mod is wrong is Pinion 4-24. Today I see the note "same profile as 3-18", (there is a lot of info on these drawings). These two gears are made using the profile shown in the small drawing on Gear 3-18. From the details given I do not think these gears are of an Involute form. I think they are intended to be a Cycloidal form, the same as the Clock Makers use. Making such cutters to use in a flycutter is simple. Using 1.25 MOD will not give the tooth thickness specified, ie 2.5 mm. From what I have worked out the tooth thickness will be 0.25 mm smaller, but still larger than gap cut by the 1.25 MOD cutter, which is 1.9635 mm.

The gears can be cut using 16 DP as the base but with 16 teeth on the pinion and 48 teeth on the gear. O/D of the pinion will be 28.57 and the gear 79.37 mm, not that far away from what is drawn.

Regards

Gray,

John, if you go down the 1.25MOD route you will need a second cutter for the 19T output gear from the gearbox part 4-24

If you have already ordered the MOD1 set then you may as well make use of that and cut something like 25:77T which would give a similar ration to the 19:57.

Drawings for Michael

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Thanks, Jason

Now at least I know that the 57 tooth gear is driven by a 19 tooth

Busy drawings aren't they

MichaelG.

Turns light off again

Hi all well owing to the chimney sweep being here this morning ,l have not placed the order for the cutters,so looking at the new info l have now ,l will say what l intend but but not place an order till you good people say l am right,to save money l will order a set of module 1 for most of the gears ,and fly cut the two gears that need say 16dp ,as they are somewhat more money, Please am l on the right road now ?

here is hoping john