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Re: Mini-mill vs. Mill-drill?

 

Oops, missing words in my last post.

One sentence should be:

The primary compromise I suspect most people think about with the "mill-drill" machines is that they are giving up THE KNEE.? And therefore, giving up a much larger work envelope

Charles E. "Chuck" Kinzer
On Tuesday, April 9, 2024 at 08:59:35 AM PDT, Charles Kinzer <ckinzer@...> wrote:


Technically, this type of mill is called a "bed mill" versus a "knee mill" (like the oft mentioned Bridgeports but also larger and smaller knee mills).

If it is in good condition, and even if perhaps not so good, I would expect one of these to produce better results on their worst day than a mini-mill does on its best day.

The primary compromise I suspect most people think about with the "mill-drill" machines is that they are giving up.? And therefore, giving up a much larger work envelope.

I view the mini-mills as just small, weak, low power, low quality, versions of this style.? It is likely that once you have a decent one of these larger versions, you might want to usher your mini-mill out the door.

I think that is probably a long discontinued model, but that probably doesn't matter.? It is very likely that the spindle is R-8 which would be good.? Hopefully some tooling comes with it.

You can go to??to see their current array (which includes mini-mills) and find the closest match to see what a new one might cost retail today.

My bona fides with mills is that I actually DO have a mini-mill that, inexplicably, I find myself using a lot even though I swear at it some.? (Most recently from the locking levers stripping inside as the pot metal crystallized or something.? Little Machine Shop replacement handles to the rescue.)? I also have a Kao Fong knee mill of a medium size of the rotating head style such as the current Grizzly G0731.? At workplaces I have used Bridgeports, a similar Lagun, and a small Clausing 8520 (which makes for a REAL nice milling machine for a home shop.)? For MY home shop, I certainly looked at mill/drills pretty seriously back in the day but got a good deal on the knee mill as I bundled it with a purchase of a Shen-Wai 12x36 lathe.? (Mill and lathe from Taiwan.)? Otherwise, I would probably have bought a mill/drill as being "good enough."

Unless you really need a lot of vertical workpiece space, I think you would be happy with a decent mill/drill.

I know you have a larger lathe, so you know what it is like to use a truly decent machine.? I think many on this group don't know what that's like as mini-whatever's may be their only experience which can, for many, be discouraging at times.? A decent condition mill/drill (so long as NOT the mini-mill version) will give you that same experience of being able to focus on the workpiece and not frustrate with the foibles of a marginal machine.

Charles E. "Chuck" Kinzer??

? ??

On Tuesday, April 9, 2024 at 03:29:36 AM PDT, Miket_NYC <mctaglieri@...> wrote:


Monday night I was looking at the latest Home Shop Machinist and saw a cover story about someone making new dials for his Jet mill-drill so theyd look more like Bridgeport dials. (This involved designing a machine to engrave the new dials, designing another machine to resharpen carbide engraving tools to needle sharp points, etc. People in HSM often go overboard in cover articles, perhaps to get to be cover articles).

I paid little attention to the modification story, but I was intrigued by the mill-drill itself. I have a Harbor Freight mini-mill (the one with the tiltable column) that I bought in 2017. It's given me good service and I love using it for drilling, but its low power and small capacity have sometimes been a trial.

For example, when I was restoring my South Bend shaper, I had to make a new gib for the shaper ram out of phosphor bronze. The SB gib is a foot long, and that's the exact length of the table on the mini-mill. So milling the edges of the gib was a mess and cutting oil grooves in it was even worse. I had to keep unclamping the work and moving it on the table, because a one-foot table gives you much less then a foot of table TRAVEL, and a table as long as the work means you can't clamp it on both ends at the same time.?

The thing that saved me on that shaper gib job was that it works fine and will never be seen by human eyes until after I'm dead. But if that had been practically anything else, I would've has to scrap the part (probably several? times), in metal that cost $100/square foot.? Also, even on the lower speed setting, this mini-mill doesn’t have much power.

But the mill-drill in that story had twice as long a table and more capacity in every area,? plus a 2 HP motor. (With real American horses, not Chinese horses). So I looked on ebay to see what they sell for and discovered that the Grizzly equivalent is for sale right across the river in Brooklyn right now, for a used price similar to what I paid for my mini-mill in 2017.


What do people think of this? I know there's criticism of round-columned mill-drills because the head can move from side to side when changing height but I could figure out ways around that, and I'd much rather have that problem than to try to make something more rigid or more powerful then it was designed to be.

?I was originally hesitant about the weight of the thing since I lived by myself and drive a VW GTI. But it looks like it can break down into pieces, and I could make several trips.

I'm sick with a cold, so I'm not visiting the seller immediately, but probably will later this week.

Mike Taglieri?
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