I know, I know! I have told customers on occasion that brushes AREN'T the solution...I just couldn't solve their problem and make a sale. You have a LOT more options. Post what you finally work out, I'm intrigued.
Would it be possible to cut closed cell foam with the hole saw and fill the inner volume to overflowing? It will compress while cutting, but expand and press out the slug when the pressure is gone.
Just a thought.... Paul
****************************I see you have one of those working brains...a rarity.
How about just mounting a spring inside the hole saw to eject the plug after it's done cutting?
How about a 1-1/16" center cutting end mill? No plug at all to eject, just chips, and not too inefficient on thin material.
I think it's a great idea. Couldn't one solder a long carbide cutter along the full depth of the hole saw? That way you wouldn't have to cut all the rest of the inside teeth back.
SW
The spinning foam will be rubbing against the stationary part during each cut. I would expect this to fail pretty quickly.
Maybe a layer of foam then a large "washer" glued to the foam (or better yet, a roller bearing, but it would have to be sealed well enough to not collect chips).
Ideally, maybe a 7/8" coil spring welded inside the hole saw and bearing welded to that (not exactly off the shelf either).
As for the stepped bit (or Fistner bit for that matter) that would be an awful lot more cutting for the same size hole it that matters...
Definitely an off the shelf item. McMaster lists several with different coatings for $50-$60.
More accurately: a small spring could be attached to the top part of the pilot drill and compressed along its length..
There used to be a product called a "Roto-Bore" (or was it "Roto-Bor"? I've got two wood cased sets covering (I think) from 1/4" to 1-1/2". The smaller ones have two teeth, the larger ones four. Each has a strongly spring-loaded 60 degree center. The teeth are ground to taper shallower inward (perhaps about 30 or 45 degrees) so the cut-through is always at the outer edge of the hole.
All have shanks of 1/2".
If used on the wood/plastic with a good backing, it should make a nice hole -- and the slug should eject when the tool withdraws.
If the slug breaks too often -- replace the spring loaded center with a flat-nosed one out to perhaps 3/4" or so.
Unfortunately, they no longer seem to be around -- though other things (for drilling in soil) appear under that name. Too many hits on Google to give anything meaningful in the first page or two. :-(
Hmm ... what about:
Good Luck, DoN.
Have they tried punching the hole? You don't have to use wood working tools to get the job done.
...Which I do often. they are sold on drilling as the part shape will allow punching but would need a complex set-up for each different part they perform the identical hole process in...
...My favorite lines are:
"I want to visit your home town on vacation, not to fix my drills. If I sell it, it will work." (12 years of business, 3-4 trouble calls total support this philosophy and all but one of those were user set-up issues.)
and...
"If there is a better product out there for your job, I'd rather see you use that. Neither of us want to get in trouble over this job or process, right?"
I often send my potential customers to my largest dealer who sells three or more competitor's brands. I'd say 60% of the time, they wind up buying mine anyhow.
I mostly agree her by the way... It's just that a single melted or stuck slug stops a multi-thousand dollar product production line. If I can find something with more of a guarantee, then I'll suggest that. But your concept is a top runner.
As someone else said, the foam is a great idea, but disintegrates. It even looses it's "pffiness" after multiple compressions.
Not off the shelf being the main reason for not going this route.
We have a plug ejection system that works 100% of the time. It uses the reverse thrust of my drill to push a plunger and I *could* make the plunger a washer-shaped device... But it is not off the shelf either and too expensive for this customer's set-up.
See my video links below for some examples of doing this with steel (round) pipe and even a 2" hole through thick material (the birds nest of chips issue recently discussed)...
No worries there. We may just go with a twist drill for simplicity if all else fails anyhow. Hogging out more material rather than just the OD with a hole saw, etc. is not a problem at all.
To be honest, I may never know what they finally choose. I generally don't even get into tooling, but if it helps make the sale... :)
My best guess is they will try a forstner (wood) bit, a twist drill or even an end mill bit... But exploring the ideas out there also fuels my future "I can solve that problem for you" activities. Thus I ask.
Most excellent idea. Probably the "top of the line" answer for them at that cost, but I'd guess the thing will last virtually forever in this material.
Yes, I'd expect a very long life in that application. I cut woods and plastics frequently on my mill and they certainly cut very easily with standard end mills. The cost is probably really low actually, I bet they'd get many months of service from the end mill.
Forstner bit? Sadly, it's an unusual size.
My Dad had a circle cutter, which had 1/4 inch drill bit in the center, and adjustable arm wtih a cutter that went around the outside.
Hey, guys. This thread has gone too long without a flame. I'm calling a penalty, until you guys can flame like you're supposed to. Everyone in the box until we get this resolved.
So buy a punch wholesale, and tell em that you're going in a new product line.
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