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How to mill a slot without a mill?
- Thread starter dml66
- Start date
- Joined
- Oct 13, 2014
- Messages
- 10,713
I've been hearing this argument for years, I respectfully disagree. At least in the sense that I doubt the bearings in a drill press spindle, are going to suffer some sort of damage if side load is applied. Especially not form normal milling operations, as I don't even think there is a lot of side load involved. The rotation of the tool is doing most of the cutting, not the advance. When I mill at a normal feed, I don't feel that much resistance.
Also drill presses usually have ball bearings that can easily take a reasonable amount of radial, side load.
I think the biggest issue with milling on a drill press is the usual lack of a drawbar and if the chuck is only held with a taper fit, that might make it prone to popping off, under side load.
Yes mills are designed to have much greater capacity for such forces but occasional milling on a drill press isn't going to kill it, IMHO...
My old Delta drill press uses a chuck with a locking collar, so it doesn’t depend on the taper to resist lateral loads. And I agree that the bearings can take some side loading for very light milling.
Where I think they impose serious limitation is in the length between bearings and the (small) diameter of the spindle. It’s just quite flexible and cutting forces will make the end mill dance around and chatter. The general lack of stiffness of the whole assembly might be less of an issue for milling light enough for that noodly spindle.
I have done a bit of milling with the Delta—aluminum only—and with light cuts it will do conventional milling. It got the job done. But it chatters and doesn’t produce a pretty finish.
If the 80-pound milling attachment on my 14-1/2” lathe with its 2+ inch spindle is barely adequate to trim T-nuts, then I’m pretty sure milling anything steel in a drill press is going to require a LOT of patience.
Rick “who’ll have to read the rest of the thread to figure out how to bore a hole in a typical DP spindle and have any meat left” Denney
Where I think they impose serious limitation is in the length between bearings and the (small) diameter of the spindle. It’s just quite flexible and cutting forces will make the end mill dance around and chatter. The general lack of stiffness of the whole assembly might be less of an issue for milling light enough for that noodly spindle.
I have done a bit of milling with the Delta—aluminum only—and with light cuts it will do conventional milling. It got the job done. But it chatters and doesn’t produce a pretty finish.
If the 80-pound milling attachment on my 14-1/2” lathe with its 2+ inch spindle is barely adequate to trim T-nuts, then I’m pretty sure milling anything steel in a drill press is going to require a LOT of patience.
Rick “who’ll have to read the rest of the thread to figure out how to bore a hole in a typical DP spindle and have any meat left” Denney
The acme screw is permanently mounted to the top, it cannot be repositioned.
Of the competitive shooters I polled, it's 50/50. I'm just a weekend warrior shooter.
Went ahead and milled the slot this afternoon on the drill press with a 2-flute end mill.
Here's what it looked like while still in the vise:
I took the advise about using V-blocks, my metal working ones wouldn't fit in the vise, I used the router and a V-bit to make a pair out of oak:
It took 6 passes to get the depth down to 0.13", same as the OEM one, used Tap Magic for lube. All things considered, this was way easier than I thought it'd be, it's not mill-perfect but it's plenty good enough. Thanks for all the help, you all rock!
Here's what it looked like while still in the vise:
I took the advise about using V-blocks, my metal working ones wouldn't fit in the vise, I used the router and a V-bit to make a pair out of oak:
It took 6 passes to get the depth down to 0.13", same as the OEM one, used Tap Magic for lube. All things considered, this was way easier than I thought it'd be, it's not mill-perfect but it's plenty good enough. Thanks for all the help, you all rock!
- Joined
- May 7, 2023
- Messages
- 2,509
This guy hits the nail on the head. Its the distance from the tip of the cutter to the bearing that is the issue. On a lot of drill presses you're 5-6" out if not more, with a mill its 2" or so. The noodly spindle only adds more issues to this.
Will it wreck the bearings in short order? Probably not, but it will degrade them in practical use due to the excess forces.
For this effort I ran the drill press at maximum speed, 3200 rpm. What I found interesting is the most chatter occurred when plunging in for a new pass, there was very little chatter when moving the cross slide laterally. I also found that pre-plunging holes along the length, then trying to connect them resulted in terrible chatter. I let the machine tell me how it wanted to run even though it seemed counter-intuitive at the time.
I'm still going to make a pitch to the finance chairwoman for a mini mill
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I'm still going to make a pitch to the finance chairwoman for a mini mill
.