Krawlin's Mill Review & Upgrades

[Krawlin]

For those of you who follow my MGT build thread you probably know I recently purchased a mini mill. For those of you who don't follow my build thread, I recently purchased a mini mill. Anyway, long story made short, I've gotten it all setup, and have been using it ALOT since then. I figured making a thread like this (review & upgrades) will help others when considering buying a mini mill. Here is a link to the mill I purchased - https://www.littlemachineshop.com/pr...ory=1387807683



So here are some of the key details about the mill I bought -

End Milling Capacity	0.6" (16 mm)
Face Milling Capacity	1.2" (30 mm)
Drilling Capacity	0.5" (13 mm)
Table Size	18.1" x 4.7" (460 mm x 120 mm)
T-slots	3 slots 0.47" (12.0 mm) wide
X-Axis Travel	11.8" (300 mm)
Y-Axis Travel	5.1" (130 mm)
Z-Axis Travel	9.3" (235 mm)
Throat	6.5" (165 mm)
X- and Y-Axis Feed Screws	0.062" (1.59 mm) per rotation
Head Tilt	45°- 0° - 45°
Positioning Accuracy	0.0004" (0.010 mm)
Spindle Taper	R8
Spindle Motor	0.67 hp (500 Watts)
Spindle Speed	100 - 2500 RPM
Power Requirements	120 V 60 Hz 8 Amps
Machine Weight	121 lbs (55 kg)
Overall Dimensions (W x D x H)	23.2" x 19.7" x 29.1" (590 mm x 500 mmx 740 mm)

Something also important to note. The following mills, including the one from LittleMachineShop.com, all come from the same factory. Sadly, made in China, but according to the comparison chart from LittleMachineShop.com, all have about the same general quality, but some have better features (and price points) than others. My personal opinion after comparing a Harbor Frieght mill (in person) to my LittleMachineShop.com mill, the LMS mill is of a higher quality. Take a look at this comparison chart, gives the stats on all of these similar mills -


(see next post for the chart, damn this 10,000 character limit!!!)

[Krawlin]

(first half of comparison chart due to character limit)

	LittleMachineShop.com	Grizzly Industrial, Inc.	Harbor Freight Tools	Micro-Mark	Micro-Mark	Homier Mobile Merchants	ToolsNow.com (Cummins Industrial Tools)
Brand	HiTorque	Grizzly	Central Machinery	MicroLux	MicroLux	Speedway	ToolsNow (Cummins)
Model	3900	G8689	44991	84630	82573	03947	7877
Price	Lookup	Lookup	Lookup	Lookup	Lookup	Lookup	Lookup
Table	4.1″ x 18.1″	3-5/8″ x 15-3/4″	3-11/16″ x 15-7/8″	3-3/4″ x 16″	3-3/4″ x 16″	3- 11/16″ x 15- 7/8″	3- 11/16″ x 15- 7/8″
T-slots	12mm (7/16″)	12mm (7/16″)	1/2″ (Probably incorrect)			1/2″ (Probably incorrect)
Spindle Taper	R8 Taper	#3 Morse Taper	R8 Taper	R8 Taper	#3 Morse Taper	R8 Taper	R8 Taper
Drilling Capacity	0.5″	1/2″	1/2″				1/2″
Face Milling Capacity	1.2″	1″	1″			1"	1"
End Milling Capacity	0.6″	1/2″	1/2″				1/2″
Swing	12″	12-3/4″	12″	12″	12″	12"
Spindle Clearance	11″	11-1/2″	12-1/4″ (10 1/2″ measured)	11″	11″

[Krawlin]

(second half of comparison chart due to character limit)

Head Tilt	45°	45°	45°	45°	45°		45°
Spindle Stroke	9.3″	5″	8.5″	7″	7″		8.5″
X-Axis Travel	11.8″	9-1/4″	9″	8″	8″		9"
Y-Axis Travel	5.1″	4″	4″	4″	4″		4"
Spindle Speed	0-2500 RPM	0-1100, 0-2500 RPM	0-1100, 0-2500 RPM	0-2500 RPM	0-1100, 0-2500 RPM	0-1100, 0-2500 RPM	0-1100, 0-2500 RPM
Motor Controller	Brushless DC	PWM	PWM	Brushless DC	PWM	PWM	PWM
Horsepower	0.67 HP (500W motor)	0.47 HP (350W motor)	0.47 HP (350W motor)	0.67 HP (500W motor)	0.47 HP (350W motor)	0.47 HP (350W motor)	0.47 HP (350W motor)
X & Y-Axis Dials	0.0625″ / Turn	0.0625″ / Turn	0.0625″ / Turn	0.050″ / Turn	0.050″ / Turn	0.0625″ / Turn	0.0625″ / Turn
Z-Axis Dial	0.060″ / Turn, 0.001 Graduations	0.060″ / Rev, 0.002 Graduations	0.060″ / Turn, 0.001 Graduations	0.060″ / Turn, 0.001 Graduations	0.060″ / Turn, 0.001 Graduations	0.060″ / Turn, 0.001 Graduations	0.060″ / Turn, 0.001 Graduations

[Krawlin]

"LittleMachineShop.com HiTorque Mini Mill is the best in its class. It has the most power, most torque, and a larger table than other mills in its size range.
The 500 Watt (0.67 hp) brushless spindle drive motor provides tremendous low end torque. And you can vary the speed from 50 RPM to 2500 RPM continuously. There are no gears to shift. And, with no gears, the HiTorque Mini Mill is the quietest in its class.
The large mill table provides 50% more table area than other mini mills. It also has 30% more travel in each direction. The resettable feed dials allow you to zero them at any point.
Grizzly Industrial, Inc. sells the Grizzly model G8689 mini mill. The Grizzly mini mill has a 3 Morse taper spindle. It comes with two 3 Morse taper collets; a 3/8 inch collet and a 1/2 inch collet.
Harbor Freight Tools distributes the Central Machinery model 44991 mini mill. The Harbor Freight mini mill has an R8 spindle.
Micro-Mark carries the MicroLux model 82573 mini mill. The Micro-Mark mini mill has a 3 Morse taper spindle. The MicroLux mini mill has one unique feature; the table feed dials both advance 0.050 inch per revolution. On all the other mini mills the dials advance 1/16 inch per revolution. The 0.050-inch per turn is easier to use than the 0.0625-inch per turn of the other mini mills. Micro-Mark will have you believe that the other mini mills have metric dials, but they do not.
Micro-Mark also carries the MicroLux model 84630 R8 mini mill. This mini mill is similar to their other mini mill except it features the 500 watt brushless DC drive system.
Homier Mobile Merchants sells the Speedway mini mill model 03947. The Homier mini mill has an R8 spindle.
ToolsNow.com (Cummins Industrial Tools) sells the mini mill model 7877. The ToolsNow mini mill has an R8 spindle."

Knowing everything above really helped influence my decision. Now if I had the garage space (and a good excuse ) to purchase a large Bridgeport mill, I would have gone that route in a heartbeat, but since I have neither, this small mill is perfect for me. Its very quiet, it doesn't take up much space, has plenty of power, and great capabilities to do what I need it to do. So far, I love it. Here is a list of some pro's and con's I have found thus far with this mini mill.


Pros---
- It's Brushless!!!
- Great specs on the table travel
- Powerful
- Quiet
- Doesn't arrive slathered in that nasty red assembly grease, just a light coating of oil and a mild grease to prevent rust during shipping
- Good price point at $650
- the X-Axis gib is easy to adjust, and the hand wheel has maybe a thousandth of play, if that, and turns very smoothly.
- Even when milling steel, it remains very quiet. The motor doesn't even break a sweat, and after a couple hours of a machining newbie (me) playing around with it, the motor was only warm to the touch.
- 12mm T-Slots, a common size for most mini mills, so clamping kits and accessories that bolt to the table are easy to find, nothing specialized needed other than a clamping kit meant for 12mm t-slots.
- R8 taper spindle is much more forgiving than #3 Morse taper, just unscrew the draw bar a bit, tap it lightly with a hammer, and your collet/endmill holder will drop enough just enough to easily remove the bit you are using.
- Comes with a small tool kit with everything you need to adjust the mill.



Cons---
- The Y-Axis gib is difficult to adjust, and easy to over-tighten it.
- The Y-Axis has a bit more play than I would like, as in, I can turn the handle wheel about 4 thousandths without the table moving.
- Each complete turn of the hand wheel moves the table 1/16th of an inch (.0625), would rather have it so each turn of the hand wheel moved the table .050, would be much easier to do alot of the math this way.
- No metric option?
- The fine feed for the Z-Axis has a good bit of play in it, maybe it just needs to be better lubricated though.
- Probably being OCD, but the axis locking levers, particularly on the Y axis, are in dumb places, where you can screw it in about 2/3 of a turn, then have to pull the knob back and twist the opposite way to reset it on the locking bolt so you can turn it the rest of the way to lock it.


Here are some pictures of it, as well as an old T-Maxx chassis that became a practice part for my first time using the mill -



















My set of endmills, 2 and 4 flute



Clamping kit






All cleaned up, small bottle of Pepsi for size reference










Stay tuned, will be posting about my first upgrade pretty soon, a solid mounted compressed air shavings removal system.

[brushlessboy16]

Very Nice setup! Can I put in orders now ;)?

[Krawlin]

Originally Posted by brushlessboy16

Very Nice setup! Can I put in orders now ;)?

Thanks Ben! Not sure if I can say yes or no to that on here, RCM-Mike might not like that. You have my AIM though.

[rawfuls]

Holy research batman!

Nice mill, I like.
Video!

[Krawlin]

Thanks!

I'll probably make a video tomorrow, going to put a cup type wire brush in it and see if I can get that circular brushed look on my spare MGT chassis.

[redshift]

Nice breakdown!

Backlash is an absolute fact of life, the only way to eliminate it would be to use an NC type ballscrew, and that would quadruple the price (at least).

.004" backlash is VERY respectable, I deal with machines with an average of .050" and some nearly .1", the older, the worse.

I agree with your gripe about the .062"/turn, that really should be .050, the standard for larger equipment is normally .1"/turn.

I would work around that by doing your layout & setup according to the .062", kind of a pain but you're stuck with that....

You'll have no lack of uses for it, congrats on the purchase.

[Finnster]

So how much did everything come to? Ie vice, tooling, etc?

Been looking at these a bit and was looking at the next size up (grizzly 704 equiv.) Had head good things about the mini mark, but also that getting a dro will solve any weird measuring due to the .065 on the other machines.

Like that size tho..looks easy to find home for it.

[Krawlin]

Originally Posted by redshift

Nice breakdown!

Backlash is an absolute fact of life, the only way to eliminate it would be to use an NC type ballscrew, and that would quadruple the price (at least).

.004" backlash is VERY respectable, I deal with machines with an average of .050" and some nearly .1", the older, the worse.

I agree with your gripe about the .062"/turn, that really should be .050, the standard for larger equipment is normally .1"/turn.

I would work around that by doing your layout & setup according to the .062", kind of a pain but you're stuck with that....

You'll have no lack of uses for it, congrats on the purchase.

Wow, actually I had no idea that .004'' was considered acceptable. The X-axis on my machine only has about .001'' right now, I guess this is higher quality than I thought!

And actually after doing a quick search, I discovered there is a kit to convert my machine over to .050'' per turn, https://www.littlemachineshop.com/pr...ory=1687114045 , so I'll definitely be purchasing that pretty soon.

Originally Posted by Finnster

So how much did everything come to? Ie vice, tooling, etc?

Been looking at these a bit and was looking at the next size up (grizzly 704 equiv.) Had head good things about the mini mark, but also that getting a dro will solve any weird measuring due to the .065 on the other machines.

Like that size tho..looks easy to find home for it.

Price for the mill was $763 shipped, Mill without shipping is $649.95
Tooling ended up being $316 shipped.
Total with mill and tooling is $1079 shipped.

Still need more tooling though. Seems like its one of those never ending things, where you can never have enough tooling for a mill, because one day you will need to use that one special bit, and then it will sit for another year before it gets used, but if you don't have it you're screwed.

Here is a price list of the tooling I bought -

Part #	Product	Price
1213	Drill Chuck, 3/8"	8.50
1236	Dial Indicator, 1" x 0.001"	10.95
1242	End Mill Set, 6 Piece 2 Flute	17.95
1243	End Mill Set, 6 Piece 4 Flute	18.95
1251	Test Indicator Holder	9.95
1254	End Mill Holder, 3/8" R8	15.95
1262	Starter Kit, Mini Mill	79.95
1638	Drawbar, R8 1-Piece, Mini Mill	9.95
1647	Vise, 3" Milling	54.95
2605	Collets, R8 Set of 7	29.95
3094	Fly Cutter Set with Tool Bits	12.95
3125	Vise Mounting Kit	9.95
3999	Arbor, Drill Chuck R8 to 2JT	11.95

And that starter kit included a clamping kit, edge and center finder, t-slot cleaner, parallels, and 1-2-3 blocks. Also, I wouldn't recommend the vise that I bought, seems kind of low quality, and the degree markings and alignment mark seem poorly cut/laid out. Lots of better vise options out there.

I will edit the first post and put a link to the mill in there, I forgot to add it when I made the post. https://www.littlemachineshop.com/pr...ory=1387807683


I looked up that Grizzly 704, that thing looks awesome, now I'm getting buyers remorse and wish I had gone with that.