Sunday, May 17, 2020

Weekend Shop Update

Seriously, I sometimes wonder why do I do these on the weekend?  The days when I could only work in the shop on the weekend are long gone, and I'm out there some amount of time every day.  I guess the reasons are twofold: first, not to overwhelm with every little thing I'm up to all the time, and second, it's the weekend and everybody's pace of posts is down, be it Sunday Music or just lower activity.

First item, the problem I mentioned about my Fogbuster not spraying seems to be resolved. I only ran it for a few minutes, but it behaved more normally in that test than any other time last week.  The problem, as a comment from reader Leigh suggested
Yeah, it sounds like the issue is between the needle and the outlet orifice of the spray head.
and it was.  I had noticed what looked like a line around the tip of the needle valve but assumed that would cause a leak - too much coolant not none.  I chucked the needle valve in the lathe and held a file against the taper briefly, then finished it with 240 grit paper, followed by 320, 500, then finally with Simichrome polish.

Next, I finished the counterweight that I included a drawing of last week.


Those are 1/4 and 5/16" dowel pins in the two holes. They're not a press fit; you can lift the counterweight off them without moving them, if you're careful. 

After that I spent time working on the approach to machine the rocker arm that gets controlled by a cam on that crankshaft.   The drawing looks like this, top view on top, face view on the bottom:


This is to be made from steel, 1018 cold rolled.  I've cut a piece of bar to be the rough it will be machined from.  The top view is a little tricky; it looks like it's 1/4" across and it is - until you get to that 1/4" square tab on the right that adds 1/16" to the width, making it 0.313".  There's not much metal in this whole piece to hold onto while you're milling it. 

The other things I'm working on are some Tee nuts for the small (Sherline) mill, my version of a product made by a company that went out of business,  and a way to make an enclosure for a little ham radio project that doesn't involve hollowing out an aluminum bar and splitting 80% of it between the recycling bin and the vacuum cleaner.




6 comments:

  1. Setting up a job for metalworking and sequencing the steps correctly has always been a bit of a puzzle to me.
    On this one, maybe mill the rectangular bar, drill all the holes while there are parallel surfaces for the vise to grab, , then mill the .062 step and the .125 step on one side, flip it and mill the .125 step on the other?

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  2. I've made sturdy, RF tight enclosures from double-sided PCB material.

    What size box do you need? Hammond has a large selection of decent quality die cast aluminum boxes.

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  3. raven:
    That's pretty much it. I'm thinking of which areas are milled by cutting across the metal (perpendicular to the long dimension) and which areas get cut along the that long dimension.

    drjim:
    What size box do you need?

    Too late. I've already committed by buying some aluminum channel stock.

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  4. Do your T-nuts have to be 10-32? McMaster sells them as small as 1/4-20. The 10-32 would be easy enough to make in a long strip and cut them to length.

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    Replies
    1. The T slots in the table are smaller than a 1/4-20 screw. I don’t really want to try to remake everything.

      I have a few of the original Tuff-Nuts from A2ZCNC and they’re better than the OEM Tee nuts. I thought I’d try to make some more.

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