Mini Mill vs Round Column Mills

Pontiac, I see a Shars?? tool grinder. How do you like it? What do you mostly use it for?
I've got one and found it easy to grind lathe tooling or sharpen the end of a drill bit. But end sharpening a 4 flute end mill and getting it to center cut has been a challenge. The Tool & Die Guy has some helpful videos, so does Stefan G.
 
mikey said:
Wow, Pontiac, that room is so clean its abnormal!
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It sure is! I've just moved my machine tools into my semi-finished shop, still have two storage units full of general mechanic's and fabricator's tools, welding suff, etc. So the only chips in there are the ones that hitchhiked their way in.

@Larry$, yes, it is a Shars. I like it very much! With a small selection of wheels, I can do lathe bits, drill bits, spot drills, countersinks of multiple types, and a few other odds and ends. I do sharpen 2-4 flute end mills (faces and flutes) but this type of grinding setup sacrifices the center cutting ability of some mills. This is often the case, where the center cutting edges are obliterated with a gash cut or a centered face cut on the end mill. Center cutting is overrated anyway. The dressed quality of the wheel will determine how small of an EM you can cut and how close you can get to the center. Cheap wheels don't retain enough fine edge material to get close. A 1/2" end mill with only the outer half of the face cutting edges intact will still perform very well, you just can't shouldn't plunge with it.

Edit: D-bits are easy to make with this grinder. You can custom grind any slot cutting profile you can imagine with a D-bit. I've been cutting little pieces of 1/2" O1 rod and making cool D-bits and countersinks as needed. Anything that saves ordering tools on a day off that I won't be able to use for a week.
 
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pontiac428 said:
It sure is! I've just moved my machine tools into my semi-finished shop, still have two storage units full of general mechanic's and fabricator's tools, welding suff, etc. So the only chips in there are the ones that hitchhiked their way in.

@Larry$, yes, it is a Shars. I like it very much! With a small selection of wheels, I can do lathe bits, drill bits, spot drills, countersinks of multiple types, and a few other odds and ends. I do sharpen 2-4 flute end mills (faces and flutes) but this type of grinding setup sacrifices the center cutting ability of some mills. This is often the case, where the center cutting edges are obliterated with a gash cut or a centered face cut on the end mill. Center cutting is overrated anyway. The dressed quality of the wheel will determine how small of an EM you can cut and how close you can get to the center. Cheap wheels don't retain enough fine edge material to get close. A 1/2" end mill with only the outer half of the face cutting edges intact will still perform very well, you just can't shouldn't plunge with it.

Edit: D-bits are easy to make with this grinder. You can custom grind any slot cutting profile you can imagine with a D-bit. I've been cutting little pieces of 1/2" O1 rod and making cool D-bits and countersinks as needed. Anything that saves ordering tools on a day off that I won't be able to use for a week.
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The ToolAndDie guy has a good video on making D-bits. I've tried it and actually got it to work. Robin has a great video on improving the Shars grinder. As per typical of him way beyond what I could do. I need to disassemble the lower shaft and see what i can do to make the fit better to the casting that holds the work. It takes excessive force to get it to hold. I might try boring it out and putting a sleeve in it.
 
ChandlerJPerry said:
Exactly as the title states, I would love to hear from anyone who has used both to hear what they prefer. I see the round columns for sale occasionally in my area, but having come from mostly using a Bridgeport at work, something about the round column just feels wrong! Unfortunately no room in my garage for a full sized BP so I'm limited to small-scale machines like the infamous Chinese mini mill or combo mill/drill round columns.
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I had the Grizzly G8659 mill when I started machining. I got another large mill-drill G0705 I use almost exclusively for milling. After a year or so with the larger mill i sold the small mill. Small mill was fine to learn on and for smaller work. The mill-drill is a round column heavy duty machine. Very satisfied with the mill-drill, round column has not bothered me at all. If I have to move the head up or down i can find an edge, center or whatever easily. I made layout points for several size R-8 holders. 3/8/1/2/5/8 and 3/4". After moving the head I install a point in the holder and move the X Y axis to suit under the point. Takes a couple of minutes at most. Just having a power feed on the X axis makes machining a pleasure.
The only problem with the smaller mill was head drop. I could not get around this problem except to come up to height ,not down. Similar to a table saw blade drop when using dado blades. Raising the blade to height will solve this on table saws and helped some on the small mill.
mike
 
@Larry$, I replaced all of my hand levers with Kipp stainless levers. Really feels positive on lockup now. I know Robin shared your opinion that the shaft is loose. His fix looked great, but I just don't think I'll need to go to that extreme (you saw the look on his face when the Moglice popped free of the shaft and he had to check if it was the casting that popped or the Moglice did). I get a 1/4 turn lockup on the main shaft on mine, so there's no cause for further modification.

C-Bag said:
as a noob I’m curious. So you don’t use the quill on Bridgeport if you‘re milling?
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Think about what is more rigid and what locks up tighter, the big dovetails on the knee, or a cam lock on a 3" diameter quill?
 
Luckily my Deckel clone didn’t have that problem with the shaft. Everything locks up fine. Where I ran into slop was in cast iron housing for grinding mill flutes. I ended up putting a brass sleeve in it. But unfortunately not needed to do any flutes yet. :(
 
C-Bag said:
Luckily my Deckel clone didn’t have that problem with the shaft. Everything locks up fine. Where I ran into slop was in cast iron housing for grinding mill flutes. I ended up putting a brass sleeve in it. But unfortunately not needed to do any flutes yet. :(
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Oh, I see, it was the free rotary/linear slide attachment that was out of spec. That would be a much easier fix, definitely on the lathe, but the tolerance must have been close! Flutes are easy, but I don't try to hit any specific diameter when doing flutes. The end mill diameter measures whatever it measures afterwards, as long as it's sharp! Pro tip: When sharpening end mill flutes, keep your band-aids close at hand.
 
These things are little snow flakes, they all have some different place where they missed the quality mark. The hardest thing was finding something square to reference from. And then when I tried to shape it square it just munched a HSS bit. Never had that before. Had to buy a carbide face mill and once I got all the sides square I used a brazed carbide boring bar on the RF to bore it to interference fit. For whatever reason that went fine.
 
I have both a mini-mill (Harbor Freight 44991, bought new) and a round column (Grizzly G1007, RF-30 clone, bought used). Used both extensively for a number of years. Being a lightweight, the mini is indeed limited in capacity. I usually use it for aluminum, but have done some light cutting on steel. It does nice work. The Grizzly is for heavier duty work on steel or on for larger workpieces. The biggest headache on the round column is that you lose XY when you have to change the head height. This is especially troublesome if you have to go from an end mill (collet) to the drill chuck. The chuck eats up a lot of the ~5" available spindle travel. There's lots of schemes out there on the interweb for holding the head true when moving it, but I don't think any of them are really worth the effort. I just get out the edge finder.

That said, my Grizzly is starting to show its age. So I've just ordered a Precision Matthews PM-835S "mini Bridgeport" knee mill. Too bad you're so far away. I'll be selling the Grizzly fter I have the PM up and running. You might want to give PM a look. https://www.precisionmatthews.com/shop/pm-835smill/

Back to your original topic - if you have any specific questions about either of my mills, either post them or send me a PM (personal message, not Precision Matthews :)

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