Introduction: Machining Mini Anvils
In this project, I machined mini anvils from aluminum. For this project you start with an aluminum rod stock and depending on the diameter and the length, your anvil can size accordingly. The video is pretty self explanatory and I used all the intermediate steps there. I started with forming the hone. Here you can first set the compound slide to a certain angle (10-15 degrees) and start cutting the horn. I eye-balled everything. I tried to make the base of the horn to be around the same measurement as the face of the anvil.
Once you are satisfied with the cut, you are done with the lathe. The next step is to put it on the vise using parallels. I laid the bottom face of the horn to be parallel with the horizontal plane of the vise. Then I cut to top part. Then flipped and cut all the other sides until I had a rectangular shaped object. Cutting the opposite face of the anvil is tricky because I mounted the anvil so that the horn was perpendicular to the plane of vise. This way I had two parallel surfaces; horn face and the back face.
- Aluminum or brass or any other metal stock
- Milling machine
- Polishing equipment.
Step 1: Lathe
You can choose any cylindrical stock for this part. As seen in the video, first you need to set your lathe so that you can cut an angle. 10 to 15 degrees is fine. Since the angle will be doubled, this will be the apex of the cone. The base of the cone could be one thirds of the overall diameter of the stock. After a few polishing cuts and polishing the horn with fine grit sandpaper, it will be ready for the for the milling.
Step 2: Milling Machine Cuts: Top Surface
In this first step with the milling machine, the work piece needs to be placed parallel to the vise by one of the sides of the horn. It is important that the two sides to be parallel. If possible, gently use a soft mallet to tap the piece into the vise and tighten it securely. At this step, you do not need to worry about the scratches on the sides since they will be cut anyway. But be careful not to scratch the horn. You can use paper or tape if you really feel worried. The important part here is to securely hold the piece between the jaws of the vise. Cut the top part until the cut meets the plane of the horn. But you can always cut it more later if you want to reshape your anvil a bit smaller or larger. So try not to over cut at this step.
Step 3: Top and Bottom Cuts
Once you have your first cut, that means your parallel planes are determined. Then flip the work-piece and align it with respect to the first cut. Keep cutting until you almost reach the bottom of the horn's base.
Step 4: After Top-bottom Cuts
After both top and bottom cuts, your workpiece should look like in the picture. If you look carefully, the bottom cut is very close to the base of the horn. However, you do not need to do that. You can always leave more room here. In this case, I wanted the horn to look a bit big compared to the body of the anvil itself.
Step 5: Side Cuts
Now that you have top and bottom planes parallel, you can secure your piece on the vise very easily. As seen in the pictures, both side cuts have been done. Here if you have a digital readout, that would be useful. Whatever dial you have, make sure your cuts are equal and symmetrical. As always, you can always cut more. Here, I wanted to be closer to the bottom of the base of the horn so my cuts are close.
Step 6: Vertical Cut
Here, using parallels between the vise, align the workpiece so that the base plane of the horn is parallel. This step is a bit tricky because you do not have much left after cutting the sides. So if you want, you can make the vertical cut before the sides. This will leave you more surface area for the alignment. The other tricky part here is to use parallels so that the horn is not touching the bottom of the vise.
After this cut, you should have a workpiece looking like in the second picture above.
Step 7: After the Vertical Cut
In the step before, the corners close to the horn are not pointy. In this step you can cut such that both corners turn into a rectangular edge. Here the goal is to cut rectangular. After this cut, you should have the workpiece like in the picture.
Step 8: Cutting the Feet/waist
In this step, we are cutting the feet or the waist of the anvil. It is important to use an endmill with round cutting edge so that our cut is circular, rather than rectangular. For the biggest anvil in the pictures, I had used a helical round cutter. If you can use such a cutter, I believe it could give you the best results. I also used an edge finder, to determine, how far from the bottom of the anvil to cut. Here you can eyeball or calculate, how much and how deep to cut. But ball park figure, your diameter of the cutting tool, should be how deep you can go. I made a few rounds of cuts and in each cut I slowly went deeper. Then using the same plane of the vise, I flipped the anvil so that I made sure, I cut at the same distance with respect to the bottom/base of the anvil.
Step 9: Reamer
This step is not really necessary. However if you want the waist/feet cuts to be smooth and polished, this step could be necessary. In this step, you do not know how deep you can go with the reamer, you need to use your senses so that you do not bend it with respect to the milling axis. If you do not feel comfortable, just skip this step. I used reamer so that I could see the fine cutting and could hear the sound changing, indicating that I was close to the work piece. Of course, here the dimension of the reamer (diameter) should be the same as the cutting tool's diameter.
Step 10: Body Cuts: Sides
In this step, you can cut the sides of the body. This step is again optional and up to you, how much much you want to cut with respect to the feet. I cut such that the base of the horn looks symmetrical with respect to four sides. After these cuts, place the workpiece perpendicular for the vertical cut.
Step 11: Body Rear Cut
This is another tricky step since you need to align your anvil with respect to the plane of surface of horn's base. You can skip this cut. However, I found out that this cut actually helps with the typical shape of the anvil. As you can see in the pictures, the bottom plane of the anvil is not perpendicular to the normal of the vise. Here keep cutting until you are close to the round cuts of the feet.
Step 12: Finishing / Polishing
At this step, you are done! Now you can use a dremel tool or hand polish your anvil. I tried a chromium finish spray with the anvil in this workshop. However, it more gave a glossy finish. Where as, when I polished the other two anvils using my Dremel tool and the proper polishing compounds, I could get a mirror finish as seen in the pictures.
Enjoy, now you have your mini anvil!