Cutting wooden disks

[Timberwolf]

(04-02-2021, 07:10 PM)Zack Butler Wrote: My hole saw the bit is what attaches to the drill.

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Make a stack by hot gluing them together..Just a small spot of it should do the job..Cut the corners off the stack {octagon}..Chuck in lathe and turn to the needed diameter..Remove and separate with a chisel...First and last discs in the stack are sacrificial....Sand the discs to smooth and remove glue..Can probably make 15 or so at one time.

[MstrCarpenter]

How many are in a "bunch"? What's the thickness? What equipment is available? These answers would affect how I would approach the task.

[Zack Butler]

I need 42 of them. Quarter inch MDF is preferred. I don't have a lathe or CnC. I do have bandsaw, drill press, routers , table saw.

[museumguy]

This type of mandrel is what is being suggested. Amazon.com: 7/16” Hex Shank Hole Saw Arbor, Fits 1-1/4” to 6” Hole Saw Quick Change Heavy Duty Alloy-Steel Mandrel with 3 BONUS 1/4” Precision Drill Bits Replacement: Home Improvement
This one has the mandrel and hole saw together. Just remove the pilot bit. You need a hole saw around 3 1/8" OD to get 3" ID.
Amazon.com: LICTOP 80mm/3.15'' BI -Metal Wood Hole Saws Bit Tooth Cutting for Cornhole Board Metal Plastic Fiberboard: Home Improvement
If you attach a fence to your drillpress, using a 3 1/2" to 4" blank. Remove the pilot bit and you should be able to drill your disks easily. Oh, clamp the material in place while drilling.

Keep in mind, this is just one way that you can accomplish your task.

[Aram]

(04-02-2021, 07:03 AM)Zack Butler Wrote: I thought of a template and router, but the disks are only 3" in diameter and I don't like my fingers that close to the bit.

Thoughts?

How about the inverse of your template idea, routing inside a template hole? You could double-sticky tape a router template to the workpiece, and double-sticky that to a backer board. Template with oversized holes, router guide follows the inside. Of course that takes a steady hand and constant pressure against the hole in the template.

[iclark]

(04-03-2021, 06:59 AM)Zack Butler Wrote: I need 42 of them. Quarter inch MDF is preferred. I don't have a lathe or CnC. I do have bandsaw, drill press, routers , table saw.

For that many, it is worth putting a little more effort into the jig.

Start with a 1x4 that is a convenient length to clamp to your DP table.

Cut a couple strips of your 1/4" MDF ~6" long and ~3/4" - 1" wide.

Glue the strips to what will be the bottom of the jig ~1" apart parallel to the board and about equal-spaced from the centerline.

Use your 3-1/4" hole saw with center drill to cut the 3-1/4" hole that will guide the next 42 cuts. (or whatever the right hole saw size is to cut a 3" or slightly larger plug)

Remove the center drill, put a sacrificial board on the DP table, install the hole saw in the DP and set the depth stop so that it barely cuts into the sacrificial board.

Now, put your MDF stock on the sacrificial board, align the jig that you made with the hole saw and use it to clamp your MDF to the table.

Cut your disk. Probably need 2 or 3 lifts to clear the saw dust. Clearing the sawdust during the cuts is what those strips are there for.

Small screwdrivers have worked well for me to get the disks out of the hole saw. Work your way around the different holes to push the disk out rather than trying to force it all of the way out from just the first hole.

[John Mihich]

(04-02-2021, 08:25 AM)joe1086 Wrote: Not sure how clean your disk edges need to be but here is one idea...

Get 3" hole saw that has a mandrel that can be used without a drill bit. Cut a hole in scrap and use the scrap as a guide for the hole saw.

That's the way I have one it.  Works fine.

[brianwelch]

I made over 200 3.5"" diameter butcher block style coasters for wedding takeaways...used a table saw to shape into an octagon, then turned it down to a cylinder on my lathe. Then used my chop saw to cut "cookies". Wish I had a reliable bandsaw so as not to waste as much material, but it all worked out well...
Just my $0.02

[FireWood]

(04-02-2021, 08:24 PM)Timberwolf Wrote: .........................
Make a stack by hot gluing them together..Just a small spot of it should do the job..Cut the corners off the stack {octagon}..Chuck in lathe and turn to the needed diameter..Remove and separate with a chisel...First and last discs in the stack are sacrificial....Sand the discs to smooth and remove glue..Can probably make 15 or so at one time.

I'd do this, but use a circle cutting jig on bandsaw instead of the lathe.

with 1/4 MDF you could have your 42 in 3 sets easily enough, scrapping the bottom one that had a pilot hole in it.

[Bob10]

(04-02-2021, 08:25 AM)joe1086 Wrote: Not sure how clean your disk edges need to be but here is one idea...

Get 3" hole saw that has a mandrel that can be used without a drill bit. Cut a hole in scrap and use the scrap as a guide for the hole saw.

That's what I have done many times for an old lockset to a larger size and just last week when I learned a pressure relief hole I drilled was way to small for what was needed yet I had removed the meat of where a pilot bit would be