Anyone with a Harrison M300 or a Boley & Leinen LZ4P?

[Dr.Al]

A while ago, a user of my website asked me to make a change gear calculator for the Harrison M300. I duly did so and sent them the link saying "please can you check it looks okay so I can publish it properly?" I never heard from them again . Ungrateful so-and-so. Took me flipping ages to figure out all the gearbox ratios as well.

A little while later, exactly the same thing happened with someone who had a Boley & Leinen LZ4P.

These change gear calculators have been sitting there waiting to be checked ever since. It would be nice to publish them as part of the revamp of my website but without anyone having checked that they give sensible results, I'm loathe to do so.

Does anyone who have one of those lathes mind having a play with the relevant calculator and seeing whether you agree with what it tells you?

M300 one is here: https://webdev.cgtk.co.uk/metalwork/calculators/changegears/m300

LZ4P one is here: https://webdev.cgtk.co.uk/metalwork/calculators/changegears/lz4p/

 

[Seadog]

Ride The Gear Train free software by Evan Lewis

 

[daedalusminos]

Not sure it's much more useful than the threading plates....

 

[Dr.Al]

Not sure it's much more useful than the threading plates....

View attachment 474058

You might well be right; I'm not sure why I was asked for it (as I said, the requester went quiet on me).

I guess it could be handy if your lathe doesn't have that chart or you want to cut some **really** obscure thread, but perhaps there isn't much point to it.

 

[Agroshield]

On the M300 one, the metric pitches only increment or decrement by 1.0 using the up and down arrows (it defaults to 1.5mm pitch). The arrows also allow a zero and negative pitch.

The imperial tpi also only increments or decrements by 1 using the arrows (11.5 tpi is used on NPT threads), similarly allowing zero and negative numbers.

Maybe it needs a note saying 'type in any pitch/tpi that the arrows cannot reach'.

It cannot find 19tpi, used on BSP. Note, in the chart above, 19tpi is the only imperial one that starts with B.

 

[daedalusminos]

Actually it's probably most useful for indicating the error on an imperial thread

 

[Dr.Al]

On the M300 one, the metric pitches only increment or decrement by 1.0 using the up and down arrows (it defaults to 1.5mm pitch). The arrows also allow a zero and negative pitch.

The imperial tpi also only increments or decrements by 1 using the arrows (11.5 tpi is used on NPT threads), similarly allowing zero and negative numbers.

Maybe it needs a note saying 'type in any pitch/tpi that the arrows cannot reach'.

It cannot find 19tpi, used on BSP. Note, in the chart above, 19tpi is the only imperial one that starts with B.

Thanks, that's really useful. I'll make the changes & report back when I've done so.

 

[Dr.Al]

On the M300 one, the metric pitches only increment or decrement by 1.0 using the up and down arrows (it defaults to 1.5mm pitch). The arrows also allow a zero and negative pitch.

I've changed them to increment by 0.05 mm now (with a minimum of 0.1, although 0.2 is the finest it can find a gear combination for with the standard gears).

The imperial tpi also only increments or decrements by 1 using the arrows (11.5 tpi is used on NPT threads), similarly allowing zero and negative numbers.

Now increments by 0.5, with a minimum of 0.5 (although 1 TPI is the coarsest pitch that it can actually find a gear combination for with the standard gears).

Maybe it needs a note saying 'type in any pitch/tpi that the arrows cannot reach'.

I think I'll leave that now that the spinners allow access with the arrows. If a user really wants something obscure, then hopefully they'll figure out they can type.

It cannot find 19tpi, used on BSP. Note, in the chart above, 19tpi is the only imperial one that starts with B.

That's a completely different route through the gearbox than the two I'd considered. Interesting. It now handles it. I've hard-coded it to show 2S as the middle gears to match the chart on the machine, but strictly speaking those gears could be anything as they're not actually used: the gear combination could be described as "BY" instead of "B2SY".

Thanks for the feedback.

 

[Dr.Al]

Anyone with a Boley & Leinen LZ4P?

 

[daedalusminos]

Most M300 owners will have the 56 tooth DP gear - it's fun throwing that in the equation.