Yet another PM-1236

[tmarks11]

scotchbrite and WD40.

++1
Remember, this is a working machine, not a car. Doesn't need a beautiful coat of wax and polish. You will get other stains on the ways as time goes on.

If you do want to use a chemical rust remover, than you can try Boeshield Rustfree. It works great, but will leave darkened spots where the rust use to be. I have used it on the cast iron top of a table saw.

http://boeshield.com/catalog/

 

[gregg]

http://www.frontiermetalcleaner.com/

You can find this at gun stores. works very well . Pulls rust right out pores of little pits. I should say cuts it out. Use it and cannot live with out it.
Gregg

 

[coolidge]

You want to remove rust...EVAPORUST!!! Will not harm paint, plastic, other metals, non-toxic, no petroleum's, no acids, you can re-use multiple times and pour the stuff down the drain when finished its that mild but it will flat out remove every spec of rust.

 

[tino_ale]

Hey guys,

I have a question about the gear change.
There is the 24T, 48T gears, then the two sided 120/127T gear. Then for imperial threading, some more Z gears.

The manual doesn't say how you change the gears, that may be obvious, but it isn't to me.

I've removed the screws and found that :
- both my tiny gear at the top position (spindle gearbox out shaft) and bottom position (threading gearbox input shaft) are stuck. How am I supposed to pull them out ?
- the double sided large gear is easy to remove, but the collar on which the bearings sit, how am I supposed to reverse it ? The bearings seem press fit onto it, as far as I can tell

Do I need to invest in some sort of gear extractor for this ? Even if I do, using it every time I need to change gears doesn't sound too convenient, or I am missing something ?

Thanks for your time

 

[darkzero]

Just my 24T gear was tight. Used a puller to get it off, threw it in the lathe & skimmed the bore. The double middle gear set does not need to be flipped, the gear under it is what gets moved, either meshes with the inner or outer gear by changing the placement of the spacer.

 

[tino_ale]

Just my 24T gear was tight. Used a puller to get it off, threw it in the lathe & skimmed the bore. The double middle gear set does not need to be flipped, the gear under it is what gets moved, either meshes with the inner or outer gear by changing the placement of the spacer.

Thanks for the feedback. I need to get my hands on a puller then...

About the double middle gear : I have a metric machine and things might be different for my gears setting.

For example (telling you this from memory) :
setting one :
top gear : 24T
middle gear : 120T
lower gear : 48T

setting two :
top gear : 48T
middle gear : 127T
lower gear : 24T

In both cas the top and bottom gears mesh to the same large gear (either 120T or 127T).

I can see how you get the lower gear to mesh with either the 120 or 127T by just flipping the spacer on either side of the lower gear.

What I fail to see is how you get the top gear to mesh with either 120 or 127T without flipping that large double gear. There is no room for a spacer at the top output shaft. If that top gear position is fixed, then, the big double gear has to be flipped, or am I missing something

 

[Rbeckett]

I too would use some scotch brite and wd-40, then coat it with way oil to keep it from rusting again.

Bob

 

[GA Gyro]

Thanks for the feedback. I need to get my hands on a puller then...

About the double middle gear : I have a metric machine and things might be different for my gears setting.

For example (telling you this from memory) :
setting one :
top gear : 24T
middle gear : 120T
lower gear : 48T

setting two :
top gear : 48T
middle gear : 127T
lower gear : 24T

In both cas the top and bottom gears mesh to the same large gear (either 120T or 127T).

I can see how you get the lower gear to mesh with either the 120 or 127T by just flipping the spacer on either side of the lower gear.

What I fail to see is how you get the top gear to mesh with either 120 or 127T without flipping that large double gear. There is no room for a spacer at the top output shaft. If that top gear position is fixed, then, the big double gear has to be flipped, or am I missing something

Not sure if this helps...

Some information in the latter posts of this thread may help:

http://www.hobby-machinist.com/showthread.php/26119-Recieved-the-PM1236-metric-to-imperial-kit-today

Seems there were some 1236's shipped with some parts metric and some imperial/SAE. I have not studied the whole issue... however the thread noted may be of some help to understand the theory behind the gear drives.

Hope this helps.

BTW: When you figure it out... please post the answers! Be interesting to understand this from both sides... that is: metric and imperial/SAE.

GA

 

[tino_ale]

Thanks for the pointer.

So it seems to confirm that flipping the large double gear involves a flip of the spacer and bearing assembly.

The ones that have retrofitted their PM1236 back to imperial had to do it only once, that is one thing, but on the 2 metric configurations I noted in my previous post, the small upper and lower gear have to engage the same side of the double sided gear at the same time.

I can't possibly reverse the large gear spacer each and everytime I need to change my range of feeds/threads.

We are missing something. I wonder if I could reverse the large double gear without swaping the press-fit spacer around. But then the gear will rub against the mesh adjustment assy. Maybe that is what the copper washer that I found in the toolbox is for ???

 

[darkzero]

I can see how you get the lower gear to mesh with either the 120 or 127T by just flipping the spacer on either side of the lower gear.

What I fail to see is how you get the top gear to mesh with either 120 or 127T without flipping that large double gear. There is no room for a spacer at the top output shaft. If that top gear position is fixed, then, the big double gear has to be flipped, or am I missing something

Look at your chart closely & you will see. In your case you will see that for metric the chart is only showing 1 middle gear & for imperial it shows the double middle gear. Same for us with imperial machines except that we need to use the double gear for metric & is why your double gear set is flipped from ours. It does not ever need to be flipped (except for those who are converting from metric to imperial)

The top gear always meshes with the inner 120T gear (in your case having a metric machine) & the bottom gear would mesh with the the 120T for metric threads. For imperial the top gear meshes with the 120T & the bottom gear to the 127T.