Modifying a hole saw arbor to make a double hole saw

TO do this make take making several special tools
I started off by grinding a holding flat on an extended length 1/4" drill bit. So I could mount the arbor on it upside down, the reason why will become apparent after a few more tools are made
Attachment 42485
Next I reamed a 3/8 flat washer to fir over the 7/16" 20 thread
Attachment 42486
Next I put the large diameter hole saw on the arbor and used 2 5/8" hardened washers as shims. The only reason I used hardened washers were they are consistent in thickness and had just the correct stack up thickness, then I placed the reamed 3/8 washer over these. This would allow the small diameter hole saw to serve as the locking nut to hold the large hole saw
Attachment 42487
Next I had to make a thread insert because the 3/4" Dewalt hole saw has 1/2-20 thread and the arbor has 7/16- 20 thread
to make the thread insert I used .032" soft mechanics safety wire.
I chucked a 3/8 bolt and the wire in one of my lathes then with the back gear engaged I ran the lathe in reverse to make a spring out of the wire
Attachment 42488
Attachment 42489
I then installed the wire spring in the small hole saw
Attachment 42490
Then tightened the hole saw on the arbor making a double hole saw for making washers out of brass shim stock
Attachment 42491
This shows the assembly from the rear
Attachment 42492

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Thanks Frank S! We've added your Double Hole Saw to our Metalworking category,
as well as to your builder page: Frank S's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/homemade-double-hole-saw"> <img src="/uploads/254489/homemade-double-hole-saw.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/homemade-double-hole-saw">Double Hole Saw</a> <span> by <a href="https://www.homemadetools.net/builder/Frank+S">Frank S</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/arbor'>arbor</a>, <a href='https://www.homemadetools.net/tag/hole-saw'>hole saw</a>, <a href='https://www.homemadetools.net/tag/modification'>modification</a> </div> </div> </div> </div>
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