Mini Milling Machine DIY - Super Robust and Precise

by alvareztelecom7

41K32533

Intro: Mini Milling Machine DIY - Super Robust and Precise

I would like to be able to machine small mild steel and aluminum parts at home for my projects. A commercial milling machine costs at least about 1000 usd / eur and even the smallest models are too big for my small home workshop. This router is slightly larger than a proxxon, smaller than a commercial type bf16 router, and costs about half (maybe a little less if you can recycle or reuse materials).


STEP 1: PREPARATION OF CONCRETE BASE

Using a white melamine chipboard mold, easy to find in any DIY or board store, we fabricate a 260 x 300 x 30mm (W x D x H) cavity. Optionally and just for aesthetics we can add some squares in the mold to obtain the final piece with a chamfer as shown in the piece that I have made.

The mold is vertically inverted, so that the lower zone of the mold will contain the upper zone of the final piece. To have 4 anchor points in the final piece, we must fasten 4 metric 6 threads at the bottom of the mold, so that they will be covered with cement. We will see these threads appear in the upper area of ​​the final piece. See position of the threads in Plane 4 of the drawings .pdf.

We mix 80% gray cement, 20% coated sand and a few grams of fiberglass in strips to reinforce the piece. Later we are pouring water to the mixture at the same time that we stir until we have a homogeneous paste.

Theoretically, the volume of the piece is 2.34 liters, but from my experience with concrete molds and because of how cheap the material is, I recommend doing more than twice the mix of cement and sand.


We pour the mixture on the mold and we are hitting from the lower area to try to remove all the air bubbles and settle the mixture. It is important that the mixture reaches the upper area and try to make a single pour. If we make two mixes or different pours, we will have a better chance of obtaining a piece with cracks or fragile.

We wait at least 7 days before unmolding. It's really tempting to do it before, I know. Once removed from the mold, we sand the edges and small imperfections. The part can be sealed to avoid grease or paint stains. In my case I have used Barpimo's stone and concrete sealer.


STEP 2: CUTTING AND MACHINING OF ALUMINUM PROFILING

We are only going to use one type of aluminum profile, in my case it has been a 30 × 30 mm Bosch Rexroth brand profile, but you can use a similar profile from any manufacturer.

In total we will need 1540 linear mm (a little more than a meter and a half) divided into the following pieces:

• 350 mm (2 units)

• 300 mm (2 units)

• 80 mm (3 units)

350 mm pieces: We will need to make 1 8 mm hole in each piece (see Drawing 3 of the downloadable PDF). On the other side and starting from the hole closest to the end, we will mount the 250 mm linear guide with a 2.5 mm hole and M3 thread.

300 mm pieces: We will need to make 2 8 mm holes in each piece (see Drawing 3 of the downloadable PDF). On the other side and starting from the hole closest to the end, we will mount the 200 mm linear guide with a 2.5 mm hole and M3 thread.

80 mm pieces: In the three pieces we will make an M8 thread on the tips, depending on the profile model, this thread could be a couple of mm lower. In addition, in two of the pieces we will make a 10 mm hole in one of the faces (see Drawing 3 of the downloadable PDF).

STEP 3: CUTTING AND MACHINING STEEL SHEET

An important part of the machine is based on pieces of 6 mm thick steel sheet (see drawings from 6 to 17 of the downloadable PDF with all the measurements of the pieces), we have two options to obtain these pieces:

• ECO option: Print template (file attached for this purpose), stick them to a 6 mm steel flat. Drill all the holes and cut all the parts with a radial grinder.

• PRO option: Make use of the .dxf files (I attach files in separate pieces and in a single set) to send them to a laser cutting company, receive the perfectly cut and drilled pieces.

The .dxf files to send to laser cutting have the holes where you have to make smaller threads than usual to avoid loose threads, so you simply have to go over with the drill prior to threading and then make the tapping with the taps.

In my case I have used normal carbon steel (without special properties) but stainless steel can be used.

STEP 4: ASSEMBLY AND ADJUSTMENT

Download PLANS HERE !Structure

* We screw the linear guides onto the 300 and 350 mm long aluminum profiles, without tightening.

* We assemble the structure of aluminum profiles as shown in Fig. X, Some joints are made with an Allen screw M8x50 and other joints are made, we have not tightened the joints yet.

* We mount the square-shaped sheet on the aluminum profiles.

* We assemble the profile structure on the concrete base with metal brackets.

* We mount bearings with support, two for the Y axis and another two for the Z axis.


XY axis

* We mount the brass nut for a 2 mm pitch on one of the «YZ nut bracket».

* We mount the 2 mm pitch brass nut on «Nut support X», it is possible that this piece will have to be filed through 2 of the 4 non-consecutive holes, due to the lack of space where it will be housed.

* On the piece «XY Axis Plate» we mount «Nut support YZ» and «Nut support X».

* We pass 4 skids through the 200 mm guides (Y axis), previously assembled in the «Structure» section.

* We assemble the previous assembly on the Y axis skates. * We mount the two 300 mm guides on «Top plate».

* We pass 4 skates through the 300 mm guides.

* We mount the two plates "X Axis Spindle Support" at the ends «Upper plate».

* We mount a bearing with support at each end of the previous set.

* On the piece «Elevador Skates», we leave two M5 x 15 mm hexagonal head screws in one direction, and in the opposite direction (that of the countersunk) we screw the plates to the runners in the 300 mm guides.

* We join the two sets «XY Axis Plate» and «Upper Plate» by means of the hexagonal head screws that we have just passed. Important to keep square before tightening.


Z axis

* We pass the 4 remaining skates through the Z axis guides.

* We mount the 1 mm pitch brass nut on the remaining set «Nut support YZ».

* We assemble the «Z Axis Support» structure of 4 welded plates on the skids.

* We mount «YZ nut support» on the previous structure.

* We mount the 65 mm diameter milling machine support on the previous structure.

* We mount the milling machine on the support and tighten.


Last settings

* We pass the 2 mm pitch spindles on the X and Y axes. We tighten the studs of the bearings.

* We pass the 1 mm pitch spindle on the Z axis. We tighten the studs of the bearings.

* We mount a crank on each of the axles, ideally they should protrude approximately 27 mm from the bearing.

* With precision squares and preferably with a dial gauge, we correct the squares and tighten all the hardware of the structure to have a perfectly adjusted machine.


Download PLANS HERE !


And finished!

I hope I have made the instructions as clear as possible. If there is any doubt or you detect an error, please comment it and I will try to solve it as quickly as possible. Thanks for getting to this point!

STEP 5: Dowload Plans and Start to Build

Download PLANS HERE !

STEP 6: Test

(Update 2-Feb-2022)

Final test of the mini milling machine for metal. With a small billet of aluminum, we tested 4 milling cutters for metal. I have numbered the 4 sides of a small aluminum billet to see the result with each of the milling cutters, the aluminum billet is 10mm thick. The strawberries tested are the following:

1. - 8mm Chinese roughing cutter (new).

2. - 8mm Chinese finishing milling cutter (new).

3. - Chinese chamfer milling cutter 8 mm and 90º (new).

4. - Izar 1-flute endmill for aluminum (very used)




After testing I have come to these conclusions:

- First of all, I need a good vise for the milling machine. This cheap drill vise will not fit the router. When holding the pieces on one side, the mobile claw tilts and the grip is poor.

- Both the roughing milling cutter and the aluminum milling cutter (1 and 4), eat material very easily, especially the roughing milling cutter. It is noted that as soon as they touch the aluminum, they pulverize it.

- The end mills and chamfer milling cutters (2 and 3) require less thick passes, it is noted that it is more difficult for them to eat metal.

- I made the mistake of making the last pass with the end mill in "Climb Milling" mode instead of "Conventional Milling", this has left the final surface worse than if I had done it the other way.

- Izar's cutter is a real wonder, you can see when I show it that it has a lot of wear and some bite, despite everything it continues to cut great and leaves a very good finish.

22 Comments

rdpoor 2 years ago

The stated goal of the project is "able to machine small mild steel and aluminum parts". The Makita router spindle speed can be varied from 10,000 - 30,000 RPM. I'm not a machinist, but isn't 10,000 RPM still way too high for this application?

alvareztelecom7 2 years ago

Yes, I thing it is too high. In any case, I have tried machining aluminum and I must say that I am very happy with the result. I'll upload video shortly.

JAKIII 1 year ago

Excellent. Do you use the high RPMs or do you use a PWM to be able to use the whole spectrum from 1 to 10,000 RPMs?

JAKIII 1 year ago

Fantastic!! I need to mill aluminum chunks that I cast into pulleys and other useful items. I will eventually buy a large mill but for right now I am in a limited space with even less limited resources. This is great. I thank you for posting your instructions. I have to find an industrial scrapyard near me to obtain the extruded aluminum and such. Thank you again

esimonee 1 year ago

Hello,
i am very interested to see the full details of the project, but unfortunately I cant fins any working mediafire link for downloading the plans. Is there anybody who has them?
Thanks in advance.

richg92051 2 years ago

Did you use some kind of speed reducer on that router head? The one I saw on Amazon had a range starting at 10,000 RPM. Way to fast for me.

alvareztelecom7 2 years ago

I only use the own regulator (potentiometer) of the Makita router. I have not controlled the minimum speed of this router, I think there is a video of a user who measured the speed in each position of the potentiometer.
The reality is that this router is designed for wood, it is true that due to its price and performance it is very commonly used in homemade machines and CNCs for machining aluminum.

vph 2 years ago

Hi, trying to download the project files I receive:

This site can’t be reachedwww.henryfab.com took too long to respond.

Regards,

vph 2 years ago

Hi again,
laser files pz_1.dwg up to pz_6.dwg are not readable. Some file error prevents them from opening. 7 to 12 are OK.

vph 2 years ago

Thanks a lot!

JetMechanic 2 years ago

Has anyone priced out proper ballcrews and recirculating ballnuts for this application? At least, for the X and Y axis? Another $100 might be worth the gain in accuracy.

bgreen3 2 years ago

If it's under manual control (no steppers or servos to hold position), then you really don't want ballnuts. They are *too* efficient and can be easily back-driven by the cutter. The increase in precision is less than the rigidity of the frame and would be harder to control manually.

alvareztelecom7 2 years ago

Hi JetMechanic. I'm seeing what you say. For example, a 300mm ballscrew with all accesories it needs, its about 56 usd in Bangood/Aliexpress. Yes, this small additional investment would be a great improvement for the machine. Thank you very much for your comment.

ItsGraGra 2 years ago

Have you looked at feeds and speeds for steel and aluminium cutting? I think you'll find a router running at 20000 rpm will quickly burn out the mill bits. You need something slower, speed adjustable and with bearings designed for the job.

Nikolaos Babetas 2 years ago

Amazing work, do you have any pictures of stuff you've machined! Are you thinking of ever converting it into a CNC? I don't think it would be really expensive to do

alvareztelecom7 2 years ago

For this model I do not plan to turn it into a CNC, it is simply a small and simple milling machine to have at home. I am preparing a video machining a part, I will upload it here as soon as I have it.
Thanks for your comment.

JetMechanic 2 years ago

This design utilizes multiple metal pieces (and necessary welding) to space the router out from the Y axis track. I suggest simply using a solid block of low alloy aluminum (or even plastic) for this purpose.

alvareztelecom7 2 years ago

I have tried to make the machine entirely with metal plates.At the point that you mention between the router and the column, the space was too big and it seemed too heavy to fit a solid material.
Perhaps another option would have been to avoid welding and make a fully bolted design.
Following your proposal, we could also have printed a part with the 3D printer (avoiding PLA please), with some durable material such as ABS.
Thanks for your comment.
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