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Little Giant clutch mandrel ?


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I am about to pour the clutch babbit for a 50lb old style little giant. I have read that I need a mandrel that is 1/2 inch smaller than the shaft it will ride on and then bore it on a lathe to correct size. 

My question about the mandrel is does it need to be tapered? I think the clutch is 6 to 8 inch tall. It seems like the mandrel would become lodged tight if I just pour right around it. I would assume I need to polish the mandrel. Will I need a hydraulic press to force out the mandrel? I have a gear puller that will grab the clutch that I can try.

 

Thank you for recommendations 

 

Mackenzie

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Coat your mandrel with a good layer of soot using you acetylene torch. This will act as a release agent to keep the babbitt from adhering to the mandrel. Remember that the babbitt will still shrink some and become mechanically tight to your mandrel.

 

As far as the taper? I'd give the required clearance on the smaller diameter and worry about the taper by machining it in when I turned the final dimension in the lathe.  

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You dont have to have any taper but I would not soot it if there is no taper in your mandrel.   (soot may or may not release on a straight shaft and if it doesnt it can be next to impossible to get the mandrel out)   I use a straight mandrel and coat it with anti-seize and have had real good results..

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my mandrel is made out of osage orange, hard maple will work well also mine has a 5 degree taper. I can bump it out with a hammer real easy. I like wood over metal as it does not wick the heat out of the babbit, it cheaper, and much lighter to handle.  sand it very smooth and wax it with paste wax then buff it good. I have poured 30 or 40 clutches with it.

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Mandrel smangerill. This will likely bring on the nay sayers but it's worked with excellent results for me on 3 hammers......

When I rebuilt this 25 lg last summer I used the shaft itself as the mandrel. With the shaft and cone removed and well prepped simply join them back together (tap the two together with a soft hammer to make sure they stay locked)after filling the grease hole (X) with damming material, remove the grease zerk, damm the space between the cone and clutch shaft with daming material through the holes, set the bull wheel face down supported by blocks (whatever) so the pin is not interfering with keeping it vertical and you're ready to pour. Yes it will come apart after the bearing is poured, simply put a block of lead on the floor, pick up the whole assembly by the bull wheel and drop it hard on the end of the shaft repeatedly till it gives up or you do (it's ok to take a break) but it will come off. Of course it's too tight so you've got to make a scraper which for the 25 lg was just a piece of MS flat stock 3/16 x 1'' bent at one end at about 80* with the radius of the bore ground to fit and sharpened so it shaves the babbit in nice little curls. Work the scraper 360* around the hole methodically from just past center pulling out material then flip the cone and do the same from the other end until the new bore can be coaxed onto the shaft, if it drops on you've blown it... :( so take care to go slowly and evenly removing the material.....Better a little tight than loose because babbit breaks in quickly..... ;) ..........Deflection?? Only slight if any, certianly not enough to inhibit the function of the hammers I've done.

 

Note: When I did the pour(s) the clutch material was removed, that is it was metal to metal.

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Another babbit pouring trck is to use oiled tissue paper, wrapped around the shaft to be poured around. Not TP, the best is the stuff that comes in new shoe boxes, it's a little tougher. 

Wrap around once with the tissue, oil it to keep it on the shaft, set it centered in the cups to be poured, dam the ends and pour carefully to avoid any voids. The shaft will tap out easily, and have the right clearance. I poured the babbets in my parks 30" bandsaw this way, and they turned out well.

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