O.S. MAX .21 flex shaft liner.

[riggerman]

Hi all on my O.S. lower unit it has a teflon liner for the flex shaft. Do's any one use stainless or brass liner on these lower units ? If so who sells them ? I remember years ago there was one available for the K&B 3.5 lowers. Regards Andris Golts.

 

[Mike Starrett]

You can make them from 7/32" brass tubing. Heat the tubing till it's cherry red. After it cools cut a little longer than needed..

Slide a piece of 3/16 flex shaft inside and just use your hands to slowly bend to shape. Cut to length.

 

[riggerman]

Thanks Mike i will make one up. Regards Andris Golts.

 

[brad nichols]

Reharden the brass tube when you have it bent to shape.

Brad

 

[BobHorowitz]

Brad,

To reharden, do you bring it up to red hot and quench in water?

Bob

 

[brad nichols]

Yes that is what I do.

Brad

 

[John Beardslee]

You can make them from 7/32" brass tubing. Heat the tubing till it's cherry red. After it cools cut a little longer than needed..

Slide a piece of 3/16 flex shaft inside and just use your hands to slowly bend to shape. Cut to length.

I've done many of these over the years, if you leave the liner long enough to fit both hands on it you can easily bend K&S tubing with out heating it. To clarify the heat treating to anneal or harden the K&S tubing is the process used for non-ferrous material (non-steel). If you heat it cherry red and quench in water it will anneal or make the material as soft as possible, cooling in air will make it partially soften and that may work for some applications. To harden non-ferrous material a precipitation process is used, the material is first annealed to as soft as possible and then the material is heated to relatively low temps like 600 degrees and soaked at that temp for a period of time usually dependent on the size of the part. Varying the soaking temp and time will delivery a range of hardness that in laymen's terms are 1/4 hard, 1/2 hard, 3/4 hard and full hard.

Thanks, John

 

[Jim Allen]

The precipitation hardening processes will only work for copper alloys that contain beryllium. It will not work for hard drawn copper alloys that do not contain beryllium. Annealing hard drawn copper alloys will leave them in a soft state that connot be reversed. However, any hard drawn copper alloy tubing can be easily bent with Cerro Bend low melt metal without annealing the tubing. The Cerro Bend metal will prevent any deforming to the inside radius even when very tight inside radaii are used.

Jim Allen

 

[John Beardslee]

Thanks Jim, trying to keep it simple here. Do you remember/know what the K&S alloy is? Is it just work hardened from the extrusion process? As always thanks, I've been out of the business along time now (72 yrs old) I hope all these people on here appreciate what a great resource you are! Keep passing on the info-great legacy!

Thanks John

 

[Jim Allen]

No Problem John,

There are at least 11 different brass tube alloys (C220, C230, C260, C270, etc.) that could be used for seamless brass tubing. All of these alloys contain Copper (Cu) amounts of between 60% to 90% with various amounts of Zinc (Zn), Lead (Pb) & Tin (Sn), but no Beryllium (Be). Tubes could be made with different tempers from H58 (drawn general purpose) to H80 (hard drawn). In the past I was unable to get information from K&S as to what alloy & what temper is used for their tubing. All of the possible brass tubing alloys are work hardened from the extrusion process. None can be heat treated. C220 drawn general purpose tubing would have approximately a 40,000 psi tensile & a 38 Rockwell C hardness.

JA

Note: I'm 76 years old. Keeping the numbers & facts in my brain keeps my memory sharp.

 

[Jim Allen]

John,

I"m still running the original hardened brass tube stuffing box tubing in my K&B lower unit. I have a grease fitting in the middle but the tubing shows no signs of wear.

JA

 

[riggerman]

Hi all finally had the time to bend a flex shaft liner out of 7/32'' brass for the O.S .21 lower unit . I noticed the side plate would not sit flush i measured the o.d. of the 7/32'' brass tubing and noticed it was 1mm larger then the teflon liner i took a 1/4'' round Dremel bit and had to open the 1/2 round liner guide for the side plate to sit flush the flex shaft turns real smooth can't wait for the ice to go off the lake to try it out. Regards Andris Golts.