[Public-List] Damn screws

[Michael Connolly]

George, 
You can perhaps make an adaptor to fit the bit to the impact driver. This would be helpful in the future. 

Also, what is more important to you the aluminum casting or the rubber diaphragm? If the diaphragm is easily and at reasonable cost replaced. Then definitely go with heat. I assume that to replace the casting means replacing the pump. Using heat, heat only the aluminum near the offending screw. Lots o'heat then let air cool. You can do this several times. I have also used a thread loosener along with the heat. Take your bit that fits and place in screw slot and tap it hard while heating. Repeat several times with heat and thread loosener. 

Failing this. What do you think the diameter of the screws is? #10 or 1/4"? Place aluminum casting on base of drill press and secure level as possible = perpendicular to the screw. File off the head, center punch and starting with new 1/16" bits, drill down thorough the screw. You might need a handful of new bits for each screw. Dull drill bits will just go sideways esp. in stainless, so use new bits. If you can, drill right through the screw into the cavity beyond the screw body. Increase the size of the bit until you reach the size of the original screw = valleys of the threads. Then use a needle pick and pick out the threads which remain. Sometimes you can get all the threads out. Otherwise just get the first couple of threads. Then start a new tap of the correct size and carefully remove the old threads being careful not to cut new threads. The idea to drill right through the screw into the cavity below is so one can use compressed air or thread loosener to blast out the debris as it accumulates. Removal of debris is critical to this operation. Accumulations of debris will jam the tap and cause the tap to rip out the original threads in the aluminum casting. Most of the time these screws go into a blind hole. Sometimes the hole is deep enough or can be deepened to allow you to cut new threads in the lower portion of the hole if the upper threads are messed up and your new screw won't tighten up. You will need to purchase a bottoming tap or make one by grinding off the end of a tapered tap. Always begin with the tapered tap and follow with the bottoming tap. Cleaning out debris as you go. 

Michael................hang in there. 

----- Original Message -----

From: "George Dinwiddie via Public-List" <public-list at lists.alberg30.org> 
To: public-list at lists.alberg30.org 
Cc: "George Dinwiddie" <gdinwiddie at alberg30.org> 
Sent: Monday, June 4, 2018 8:11:29 AM 
Subject: Re: [Public-List] Damn screws 

On 6/3/18 9:54 PM, americo silva via Public-List wrote: 
> screw bits are not that expensive must b a hardeware store around 

Oh, I've got screw bits that fit the screw, but they don't fit the 
impact driver. 

-- 
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When I remember bygone days George Dinwiddie 
I think how evening follows morn; gdinwiddie at alberg30.org 
So many I loved were not yet dead, http://www.Alberg30.org 
So many I love were not yet born. also see: 
'The Middle' by Ogden Nash http://idiacomputing.com 
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