Partner 65 / Vintage chain brake mechanisms

[Al_Smith]

Here it comes .I'll apologize ahead of time with the amount of pics but I don't how else to do with it .This first shows the handle with the sleeve with a slot that the small roll pin goes through . That movable sleeve gizmo is what sets or latches the brake in conjuction with another piece in another post I'll do one pic at a time and try to explain how it works the best I can .

[Al_Smith]

Moving right along .This shows the release which by rotating forward by contacting a pin on the bottom portion of the handle releases the tension on the spring which clamps down on the drum .Now at the same time mentioned in the previous post it rocks the lock from the small roll pin .

 

[Al_Smith]

Now another showing the cam or whatever you want to call it .

 

 

[Al_Smith]

Last one .This shows the Belleville washer and the roll pin every thing rotates on .Now if I can get it all back together that might be a real feat of patience .

[Al_Smith]

Just as a follow up it took me about two hours to reassemble this @#*%&& thing back together .As I've said before chain brakes are not my friends . >:(

[flagoworld]

What a legend. Thanks so much! It all makes perfect sense now. I will post again in a few days when I have some drawings and prototypes done to show the progress.

[Al_Smith]

If your going to duplicate it  you need that Belleville washer or it won't latch .Voice of experience here because I missed aligning it  two times on reassembly .This one I had to walk away from three times before I got it .
Funny thing about these brakes because they were an option in the day .For example the P-100 did not even list them nor the Mac PM 1000 but the P100 super ,a later adaptation  did .--The S-65 did though as well as a non brake cover .
Now the odd thing about that is the cover I used came on a Mac 1000 and the P-100 super I have is no brake . However on saws that are in the neighborhood of 40 years old you have no idea of the history .Except they will run like a scalded ape 8)

[flagoworld]

Makes perfect sense about the washer. That keeps the lever detainer plate affixed to the sidewall and shtiff so it doesn't flap in the breeze when the lever passes by it, yes?

Based on your pics and the pics of parts that have been for sale on the past for this saw on chainsawr, I was able to come up with this mechanism in CAD. It looks like it should work! I modeled the housing, too, and it fits inside that tiny housing! (hidden so you can see the mechanism).

I'll be attempting to build it soon. Will keep you posted.

Also, yeah, this thing really runs. That is why I want to save it. Starts with 1 pull. I disassembled and reassembled much of it and it is all very clean. Someone loved it before me.




 

[Al_Smith]

On the subject of the brand itself these two P-100's I restored are the only two I've ever owned or worked on .It's been a learning experience .
Why as a brand they never captured more of the market I'll never know .The way they are built they are almost bullet proof .I think one of mine died because of a faulty ignition but looked like it had spent some time on the bottom of the Pacific ocean .
I broke it loose with a grease gun and the insides were clean as a pin except the rings were frozen .At the moment I have a 20" bar on it .Do the math 99 cc and short bar .Plus it also fires on one warm but wears a D-handle because it does have some compression and the after market 272 Husky coil is a hot one .It blows a nice hot blue spark at relatively low speed which can be a kick back hazard .----well good luck,hope it works out 

[Al_Smith]

On the subject of CAD I never got into it but  it is fascinating .I spent the last 15 or so years of my working life working with  CNC programs and robotics but stopped short of CAD because it was not part of my job .
On something like this I can see writing a program and dumping it into a CNC controlled milling machine it could just spit out the parts .On my old 1938 Bridgeport mill it would take me a month of Sundays and many attempts .
A thought however occurred to me .Since the almost same things were used on the s-65 and the P-100 if they are not the same parts .I never crossed referenced them myself .If so I would think possibly the design might be in use on other things perhaps by different manufacturers .Like for instance who knew a Husky 272 coil  might work in place of that two piece electronic ignition system  ? I guessed and got lucky . ;)

[Al_Smith]

I had some time on my hands so I took the liberty of researching those parts numbers --From the P100 Super brake band # 303829 ,Cam # 269270 sleeve# 269275 .
On both the P-70 and the S-65 these same numbers are used except they had a 505 before them .So it would appear they are all the same .There may be other models  included in that .

[flagoworld]

"They don't make em like they used to"... The way I see it, material science and manufacturing is so much farther developed that they are able to understand the limits of materials much better and manufacture precisely to expected limits, optimizing material use and manufacturing complexity. But as a side effect, especially with consumer products, using them beyond their intended limit or even close to it for extended periods seems to more often than not cause very premature failure. It does seem like a lot of older things are "built to last" in the sense that they inherently have a little more tolerance for abuse. I am amazed at how well a lot of these really old small engines run.

I wish I had a milling machine. I am planning on making a smaller one at some point. The tech is so readily available and cheap now, it's like lego parts. I have been more in the computer scene my whole life, but absolutely love bringing those creations to reality. 3D printing has been an amazing outlet to that end. Still hand-fabbing metal like a peasant 🤪... Soon... soon...

[Al_Smith]

In some applications high impact plastics are more robust than die cast aluminum  alloy and some it's not good ..I've seen in it automobile engines and what used to leak oil doesn't any more .Plus engine noise is greatly muffled .
However one popular make of saws has problems on it's greatly popular climbing saw .The chain brake handle, which is plastic, breaks which is not a good thing . 

[flagoworld]

Is it against the rules to post a youtube vid?

I made a rough prototype the mechanism in metal after confirming it worked in plastic. It appears to work!!! I still need to clean it up and add the detent on the lever so it catches on the plate properly and with the right amount of force. Then I will 3d print a nice big handle and screw it to that metal lever.

https://youtu.be/F7qhKvjZpdk

[Al_Smith]

As per the design which quite honestly fools with my pea sized brain the "sleeve " has to engage the handle to reset .

[flagoworld]

Yeah I still need to add that part. Hoping to have it dialed in over the next couple days. Even without that detent retainer it seems to somewhat retain itself. Though it would probably trip itself in the current state heh heh.

[Al_Smith]

In looking at that cover I think perhaps it was designed for a non brake application .What's missing are the little nubs of the casting around the outside of the band present on the one designed for a brake .I'm not sure of that would be a problem or not .I'll take the cover from the P-100 super today which has no brake and take a pic .

[Al_Smith]

In taking a second look now I think I see those tabs that hold the band .Belay my last .