Tools – Tinker and Futz

Brass Carving

The Tinkerer — Sat, 06 Sep 2014 18:35:18 +0000

I’ve been branching out a bit from my CNC router use in woodworking and into some heavy metal. Besides Floor and Pallbearer, I’m also talking about aluminum and brass.

I’ve made a few brass branding irons. I used standard woodworking v-bits with good results. I just make sure I use one of my older bits.

I recently was asked to produce a 3d carved brass item for a client. The item was very intricate and would require a very fine tipped bit. Since I had just performed a few adjustments to the ShopBot to improve accuracy, I knew the machine was up capable of the detail. My questions were related to bit selection and speeds. I started to do some research to find what the experts recommended.

Tapered, ball nose bits with a very small tip are the way to go. Machines like the Carvewright have been delivered with this kind of bit since their inception. The main reason is that they perform quite well on the small scale carving that is generally performed on these machines.

These bits are generally up-cutting to aid in removing chips. They often come with a coating that is intended to extend edge life or keep cutting temps low.

The bit I chose to try out was the 1/4″ shank, 6.2deg tapered ball nose bit made by Amana Tools.

What’s So Special About Engraving Bits?

The Tinkerer — Wed, 03 Sep 2014 23:38:40 +0000

I was recently asked to create a pair of commemorative plaques. Essentially something like a diploma or other certificate, except these were to be carved into wood. No problem, right? I had carved plenty of signs before.

Well, the difference here was the scale of the lettering and the detail of the carving. I decided it was time to step up to some proper engraving bits.

I had been using standard v-bits for all of my sign making up to this point with no complaints. Here’s the problem, when you are carving at very shallow depths, like say 1/32 deep, the tip of a standard v-bit does a pretty bad job. The closer you get to the tip, the less cutting you are able to do because the bit is nearly stationary. Think about spinning a thumbtack on it’s tip. The flutes on the bit are so close together and shallow that you end up denting the wood instead of cutting it.

Here’s where engraving bits come into play. The tip of an engraving bit is not directly in the center of the bit. It is offset by a specific amount depending on the bit you buy. This offset allows the bit to do a much better job cutting at shallow depths. The result is more legible lettering and better detail on very small details.

There are several different angles, offsets, and tip geometries you can choose from. I picked up a set so I could try a few different configurations.

Try out the Amana Tools In-Groove bits. They allow you to replace dull blades on a single shank saving you lots of money.

Can Your CNC Router Replace Your Planer?

The Tinkerer — Tue, 08 Apr 2014 16:47:29 +0000

When we think of CNC routers and their capabilities we often go right to the feats of complexity and precision. Impossible inlays, hundreds of exact copies of parts, complex shaping and carving, and perfect joints but not everything you use your bot for needs to be so complicated.
Flattening table tops is by far my favorite “alternate” use for my bot. I make a lot of tables and I used to haul the tabletops to a shop to have them flattened on a 4ft belt sander. They would turn out beautifully flat and smooth. On the other hand it would take time to make the trip and the shop would have at least a 2 day turnaround. There is also the risk of damaging that gorgeous glue-up in transit.

I decided to try to keep the work in my shop so I picked up a nice 2.5″ flycutter and laid a rough sawn board on the table. After a little tweaking to make the z axis perfectly perpendicular to the table, I was very happy with the results. I’ve done several tables this way. I’ve even experimented with ball-nose bits with large radius ends to create a scalloped finish.

One tip to keep in mind is to pay attention to grain direction and bit rotation. Set your stepover to a small percentage like 10% and be sure you are following the grain of the wood with your cuts. With a 10% stopover you can get very close to cutting only along the grain. Larger stopover settings will result in more cross grain cutting. This will leave swirls in your material and require you to spend a lot more time sanding.

You can accomplish this same thing with smaller bits as well. Give it shot and let me know if you have other “alternate” uses for your ShopBot.

Cut on the Up and the Downstroke

The Tinkerer — Fri, 04 Apr 2014 06:08:41 +0000

After you’ve been using a CNC router for a while, you begin to look for ways to make your life even easier (as if having a robot do work for you wasn’t making it easy enough). For me, sanding is a necessary evil. Plywood is especially prone to fuzzy edges and chipped veneer both making your job take longer. After the CNC has done it’s work you are left with lots and lots of sanding to get those edges looking nice.

Here are a few tips to cut down on that pesky cleanup time.

First off, make sure your bits are sharp. Your bits can churn through hundreds of feet of cutting in no time and you shouldn’t be surprised at how quickly they dull. Nothing compromises your edge quality and sharpness of cut like a dull bit. As soon as you see your cuts getting fuzzy, it’s time for a sharp bit.

Secondly, consider whether you are performing a conventional or climb cut. I have found climb cuts perform better in plywood than conventional cuts. To see for yourself, compare your parts to the waste material. If the waste material has a cleaner edge than your part does, you should switch the direction you are moving from conventional to climb or vice versa.

Finally, consider the bit you are using. I have fallen in love with compression spirals like the Amana 1/4″ and 3/8″ bits from Toolstoday.com. Upcut bits are great for clearing chips and preserving the veneer on the bottom of your sheet goods. Downcut spirals are great for a clean top edge. Want a clean edge on both top and bottom? You’ll need a compression spiral.

These bits combine the benefits of an up and downcut bit in one. The end of the bit (B1) is shaped to pull chips up and the rest of the bit cuts down. The result is a bit that doesn’t chip the veneer on either face of your plywood or laminated sheet goods.

I’ve been using these Amana bits for a few months now and I love them. They have become my goto bit. While they may be a bit more expensive than your standard single direction bit, the time saved in sanding and cleaning up ragged edges more than makes up for it.

My new favorite CNC router accessory

The Tinkerer — Sun, 02 Mar 2014 07:08:51 +0000

Being a tinkerer, my wife often tries to surprise me with tools for gifts. She even wanted to give me a Thermal Dynamics a80 Plasma Cutter machine. Last Christmas she bought what has become my #1 favorite tool to use when working at the 4×8 CNC router.

This nifty Rockwell Sonicrafter multitool is great for lots of oddball jobs where other tools fail.

For CNC router cuts, I work without a vacuum table so almost all of my parts have tabs to hold them in place while the bot finishes my cuts. Armed with a small cut-off blade, this tool has found a permanent home plugged in next to the ShopBot where it is at the ready to cut through the tabs on all of my work. You can flush cut right up to your finished part without having to wrestle a sheet of sliced up plywood hanging off the end of your table.

I like big bits and I can not lie

The Tinkerer — Fri, 21 Feb 2014 06:02:54 +0000

I had the opportunity to visit ShopBot headquarters a few months back. While chatting with their training master TJ, he bragged about his great big 2.5 inch fly cutter bit. I have to admit I was envious. My bit was half the size.

I finally had the opportunity to pick up a bit to rival his.

I got myself a 2.5 inch Amana Tools fly cutter. Tonight I had the first chance to put it to use on my severely gouged up spoil board.

First off, this is a hefty piece of tooling. It looks a bit intimidating and weighs at least a couple of pounds. It has 4 carbide inserts (2 to flatten and 2 used as scoring cutters) meant to carve a smoother surface than traditional 2 cutter styles. All of this is mounted on a 1/2 inch shaft. It is easily the largest bit in my drawer. This thing is a monster.

After I created my tool path and chucked it in, I spun it up for a trip across my table. The first thing I noticed was the sound of the bit cutting through the air. At 14,000 RPM the size of the bit moves a heck of a lot more air than the 1/2 inch cutters I use every day. The sound of the bit as it started cutting is equally as surprising. On my MDF spoilboard, I was reminded how quiet sharp high quality bits can be. I think the combination of scoring cutters and flattening cutters adds to the low dB levels.

The cut quality is pretty impressive as well. The surface is perfectly smooth with brand spanking fresh sharp cutters. Here’s the best part about these insert style bits. Each square carbide cutter insert can be rotated after you dull your edges. This means you get a fresh cutter 4 times before you have to think about replacing your edges. I love that! I wish all of my tools worked like that.

I can’t wait to use it to plane a hardwood tabletop. I’ve used a smaller flycutter bit to surface tables before. I get decent results but this giant will be sure to plane a surface that needs even less sanding.

I wish I hadn’t waited so long to follow TJ’s advice. This thing is great.

An intro to 5-axis CNC machining – part 1

The Tinkerer — Mon, 25 Feb 2013 20:22:14 +0000

I had the opportunity to tag along on a road trip with some members of the ShopBot team. They were headed to a shop in Wisconsin to help a customer with two ShopBot machines, a monster 16×5 3-axis machine and a brand new 5-axis machine. I have to admit I was there for the 5-axis. I had not seen their machine in action and I was excited to see it run.

3-axis: A machine that can move a tool (commonly a spinning cutter bit) along a horizontal plane (X-axis and Y-axis) such as a piece of plywood, as well as move vertically (Z-axis) to adjust the depth of cut and carve things such as a topographical map. The adage goes that a 3-axis machine can cut valleys and carve “mountains” but is not capable of creating “caves”. You could cut parts for plywood furniture or create 3D carved signs.

5-axis: A five axis machine starts with the same 3-axis movement as above. It adds two rotational axis by adding a “shoulder” and “wrist” or by allowing the actual workpiece to move in 2 axis. A 5-axis machine can carve a complete 3-dimensional object from a block of material. You could use a 5-axis machine to carve a bust of Beethoven for your piano.

One of the most important aspects to any cnc machining work is figuring out how to hold your material in place while the machine makes it’s cuts. A CNC Maching service can assist with a range of projects. Material holding even more critical with 5 axis machining especially when you consider you may be cutting away the bottom of your block of material. Material stiffness is also a concern since any flex in your material will degrade your cut quality. You can find out about Sliger Machineworks and learn all about this type of machining. Used for removing jammed or stripped nuts without damaging the bolt, a nut splitter is an essential tool in the kit of an onsite engineer.

In addition, one of the most essential things you can do to preserve your expensive equipment is to lubricate it properly. You will be rewarded with longer living and better performing equipment if you choose the right lubricant like Altemp and apply it properly. If you need an additional cnc machining equipment, purchasing used cnc machinery equipment is worth considering.

Many people employ jigs, screws, or adhesive to secure their material.

There are 2 flavors of 5-axis machining. “3+2” and full 5-axis.

During “3+2” machining, 2 of the axis are locked while the other 3 move to do the machining.

During 5-axis machining, all 5 axis are in motion while the cutting bit is in contact with the material.

This video shows an object being carved using both methods.