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Best way to hold 3/4" straight shank in Morse taper?

andyinabox

Plastic
Joined
Oct 6, 2021
Hello there -- I'm new to this forum (and machining in general), but I thought I'd throw this out there and see what people have to say.

I'm trying to get tooled up for cutting miters on bicycle tubing without breaking the bank. Also, I'm working out of a maker space so working with what's available there.

From what I've been able to learn from more bicycle-specific sources, regular hole saws should work fine as long as the setup is rigid enough to withstand side loads when the saw tries to wander off. The shop I'm in has a pretty heavy duty Grizzly G0793 that comes with an MT#4 spindle and MT#2 and MT#3 adapters, as well and drift pin for tool removal

The more rigid hole saw arbors I've seen have a 3/4" straight shank. I see that there are collets that will directly insert into a morse taper, which would probably be ideal for me because I could just buy a 3/4" one and be good to go (I think). But it seems like these tend to be used on a lathe with a draw bar. Is there a good way to use this style of collet in a drill press / milling machine situation?

If not, any suggestions for a relatively inexpensive collet chuck or something else? Again, all I really need is to be able to hold a 3/4" straight shank in a MT2, MT3, or MT4 spindle.

Thank you!
 
Joined
Jan 15, 2005
Location
The Netherlands
Thats a drill press not a milling machine Not gonna work if you cannot push or pull the morsetaper in its cone
You cannot tighten the collet and with a ER colletsystem the sideloads will get it loose
Also bearings of a drill press are not designed for a sideload
But beside the bearing issue you could take the spindle out and OD thread the spindlenose
Then make a fitting nut to push the collet in
Make sure to lengten the collet with a bolt to be able to remove it with the drift pin

Peter
 

kb0thn

Stainless
Joined
May 15, 2008
Location
Winona, MN, USA
I haven't seen a small hole saw arbor with a 3/4" shank. That seems a bit excessive for a hole saw that is what, 1 or 1-1/2" in diameter?

Pretty much every shade tree race car fabricator uses a junk drill press with junky tube notcher and gets away with it. In college we built our Formula SAE car and Mini Baja cars with a Chinese floor drill press and normal 7/16" shank hole saw arbors. I don't recall the chuck ever coming out of the drill press doing that.

I think I would make or buy 1/2" straight shank arbors and just use them in a 1/2" chuck. I suspect that will be comparable with your 3/4" shank arbor but not need any change in machine configuration.

Something like:
Hole Saw Arbors - Tools
but with shank turned down to 1/2"
 

David_M

Hot Rolled
Joined
Sep 30, 2014
Location
Midway, GA, USA
I would want the hole saw's teeth as close to the spindle bearings as possible. What I would use is a 3MTA arbor, threaded with 1/2-20 threads:

All Industrial 49707 | 3MT Shank to 1/2"-20 Threaded Drill Chuck Arbor Hardened Morse Taper MT3 Adapter - All Industrial Tool Supply

Screw the hole saws directly to the 1/2-20 threads.

You may need an adaptor (1/2-20 to 5/8-18) for the larger hole saw for the bottom bracket tube such as:

Allstar Performance ALL10402 Tubing Notcher Adapter for Allstar Arbor | eBay
 

andyinabox

Plastic
Joined
Oct 6, 2021
I'm just going by what I've seen from bicycle framebuilders. The tube walls are very thin, like .6-.8mm in standard tubing and even less for nicer ones. I think that changes the game a bit as the miters need to be more precise with so little material, and it's more likely to tear with chatter.
 

andyinabox

Plastic
Joined
Oct 6, 2021
Ah yes thank you David_M!! I think this is what I'm looking for, at least for this particular machine. I had seen the 1/2-20 arbors but hadn't even thought about just getting an adapter *facepalm*. I know it's still just a drill press, but it's pretty beefy so seems worth a try for < $30.
 

Tony Quiring

Titanium
Joined
Nov 5, 2008
Location
Madera county california usa
Thin wall tubing will require controll cut or fine teeth in the cutter.

Slow speed will allow longer life.

If using drill press use a fixture

Simple enough to make from dimensional lumber.

Drill hole on way to hold stock and another where the cutter will go.

Clamp well and secure stick then proceed.

The lumber will support the side loading of the cutter much better.

Sent from my SM-G781V using Tapatalk
 

andyinabox

Plastic
Joined
Oct 6, 2021
Just wanted to post an update, I took David_M's advice and got the threaded arbor + adapter he suggested, and it worked like a charm! Only cost me about $30 or so and I was able to just attach my hole saws directly to the arbor. Works great even with some of my older beat up hole saws!

IMG_20211012_194514570.jpgIMG_20211012_194514570.jpg
 








 
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