I made a Dust Collector – Part 2

Curse you Wandel, for stealing my thunder!

Whatever. Nobody cares about your little website anyways.

 

So, at this stage of the project I had an impeller and a motor, and nothing in between.

I needed something in between.

Fortunately, my motor came with a pulley attached.

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…Very securely attached…

I cobbled together a gear puller with some scrap metal, clamps, a magnet, and a coupling nut.

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Now that I had removed the pulley from the shaft, I proceeded to remove the coupling nut from the pulley…

Impeller - Motor Pulley

 

Impeller - Motor Pulley

 

Over at the lathe, I began to cut away at the pulley to turn it into a hub.

Impeller - Hub

Impeller - Hub

 

Aaaaaaand, it’s a hub.

Impeller - Hub

 

I laid it on the center of the back of the impeller and marked the locations of the  holes I had drilled in the hub since the last picture…

Impeller - Mount

Impeller - Mount

Off camera, I drilled out the holes and attached the hub to the impeller and the motor shaft.

Impeller - Test

I hooked it up to a foot pedal switch and it was time for a test!

 

Holy crap! Time to change my underpants!

 

…to be continued.

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I made a Dust Collector – Part 1

A while back I bought a leaky air compressor for $50 because it had a good 3HP motor on it that I figured I could use someday for something, probably.

When Mr. Wendel built a small dust collector with a tile saw motor, I knew my old motor had found its destiny.

Little did I know that this would lead to one of the scariest things I have ever built (and I’ve made a good number of catapults and potato cannons in my day).

I needed to make three things: an impeller, a cowl, and a motor mount.

Everything I needed I already had laying around, so I figured this would be a good way to use my tools and my time. At the very least it would be an educational experience.

First: Thing 1 – Impeller

To start, I cut some 1/4″ plywood into two identical discs by taping two squares together with double-sided tape and then spinning them across the blade on a screw I had driven through a thicker board (a rudimentary form of a dedicated circle-cutting jig)
Impeller - discs
Impeller - discs
Impeller - discs
Impeller - discs

A piece of oak I had in my scrap bin became the impeller fins. I printed out a template and glued it to the piece of wood and then cut out the pieces freehand on my bandsaw.
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Impeller - Fins

Since this was a remnant piece of wood, it was not the same thickness all the way through, so I removed some wood from the top of each fin after setting it against the bottom of my milling machine vice to ensure that they were all the same height.
Impeller - Fins
Impeller - Fins
Impeller - Fins
Impeller - Fins

Using 9 fins, the math was easy, I placed a fin every 40-degrees around the bottom disc. The tilt was determined based on what looked best to me, then I just measured the offset from the 40-degree lines and placed the tip of the fin on one line and base of the fin on the other.
Impeller - Assembly
Impeller - Assembly
Impeller - Assembly

After setting everything in place dry and ensuring in all aligned properly, I applied glue to the top and bottom surfaces, set them in their pre-determined places around the bottom disc, and then set the second disc on top.
Impeller - Assembly

I didn’t want to mess with clamps, so I set the assembly on a known flat surface (my table saw) and set another known flat surface on top (yes, that’s the table top from the old scroll saw) and piled some heavy metal pieces on that.
Impeller - Assembly
Impeller - Assembly

After letting the glue set overnight, I took the assembled impeller to the drill press, where I used a 4-inch hole saw to open one side as the air inlet.
Impeller - Inlet
Impeller - Inlet

Next I set a large ball bearing on top of a metal cylinder in the vise and balanced the impeller on top of it.
Impeller - Balance
Impeller - Balance
Impeller - Balance

I used a forstner bit to remove wood from the heavy side until the impeller stayed level while balanced on the bearing.
Impeller - Balance

So, now I had the impeller… part 1 complete.

Fixing a Fancy Bolt

When I first started using my lathe, I noticed that one of the two small bolts that secured the compound to the cross slide was stripped, and couldn’t be tightened down fully.

But since the other one worked and the compound seemed stable, I postponed the replacement of this bolt.

Recently I had been using my lathe for a lot of stainless steel parts, and the added strain of the harder metal took a toll on the remaining bolt; to the point that, when I tried to tighten it down the other day, it also stripped.
Lathe compound repair

I could procrastinate no longer, I had to fix this thing.

The problem was that the heads of these bolts was a semi-rounded T-bolt and I wasn’t sure if I would be able to find a replacement part easily. Plus I wanted to use my lathe NOW, not wait for shipping.

So I decided to recycle the bolt heads.

Here’s how it went:

First I took the nuts from the bolts and dug through one of the spare parts bins to find a machine screw with the same thread size and diameter.
Lathe compound repair

After this was accomplished, I bashed my knuckle.
Lathe compound repair

Then I place the old bolt shafts in the lathe and drilled the head off after center-drilling and countersinking it.
Lathe compound repair

Lathe compound repair

Lathe compound repair

Next I worked the new screws with a file in my lathe until they fit the countersunk hole nicely.
Lathe compound repair

After I was satisfied with the fit of the heads, I brought them flush on the milling machine.
Lathe compound repair

Then I took them over to the welder and glopped a Cheerio of molten metal on top. This didn’t have to be a very strong weld, just enough to keep the machine screw head from spinning in the T-bolt head.
Lathe compound repair

I used the milling machine again for cleanup, and once I trimmed the bolts to length, I was back in business.

Lathe compound repair

lathe repaired

Polespear Upgrades Update

After my previous modifications resulted in a slow spear that kept maiming and releasing fish, I went back to the shop and made it better.

To increase the speed, I ordered a 1/2-inch diameter band, but that turned out to be so stiff that I could barely stretch it, and if I did it bent the spear, so, that didn’t work.

Then I tried just adding a second band to the spear.
Untitled

This actually worked quite nicely. I had effectively doubled the power without making it too difficult to stretch.

Win.

Now to solve the problem of the fish wiggling off the spear.

I wanted to add barbs to the spear tips, so my first thought was to use a file. After looking at my file assortment, I realized that this would remove too much metal, and the barbs would really just be notches, they wouldn’t extend beyond the diameter of the tip, so I’m not sure how effective the would be.

So I instead cut slots at an angle with my hacksaw, and then was able to bend the metal outwards to form a proper barb.
Untitled

Done, and Done.

I went out to test it later that evening.
I didn’t see many fish for a long time, which is always a limiting factor in these tests.

But then, as the sun was going down, I saw a decent sized black perch and squeezed the trigger.

BANG!

The extra power made all the difference and the fish never knew what hit it… because it’s a fish.

The barbs were probably unnecessary in this case, since the polespear nearly blasted straight through the cute little fishy, but they certainly made the fish more difficult to remove from the spear, so I consider them a success as well.

Too bad I don’t like the taste of perch.

I gave the fish to the cats on the jetty and went home with a puffed chest and a bounce in my step.

I’m beginning to think of this design as a poor man’s speargun.

I like it. It’s simple and effective.

But now it has me thinking of other ways to make a cheap speargun…

Stay tuned…

Funting with a Polespear

I have recently added a new hobby to my life.

The timing couldn’t be worse, really.

I already have a 2 year-old daughter, a baby boy due any day, a full time job, a wife, and a large number of unfinished projects, but now I have to accommodate the compulsive urge to kill fish with pointy objects.

I grew up in the Seattle, Washington area and always enjoyed fishing, but somehow, since moving to San Diego 10 years ago, I haven’t found to time to go fishing.

I guess the problem is that I’m pretty busy with many other areas of my life, and it’s hard to justify spending a few hours on a weekend sitting and  waiting for a fish to commit seppuku with a hook on a string.

Then I discovered spearfishing. Spearfishing is different, it’s like snorkeling with a purpose. It’s not just sitting around waiting, or even just swimming around and looking, it is hunting. Fish hunting. Funting. 

I’ve gone twice now, and I’m mildly obsessed.

As is the case with most of my hobbies, it’s not enough for me to just participate in spearfishing, I have to improve on it, customize it, make it better, or at least make it my own.

To this end I modified the tried and true polespear to add a trigger mechanism.

The polespear design is simple: it’s a spear with a rubber band attached to the base. To kill a fish with it, you hook the rubber band with your thumb, stretch the band toward the tip of the spear, and then grab the spear shaft near the tip in order to hold the band under tension. Then you point it at a fish nearby and loosen your grip, allowing the spear to lurch forward; ideally impaling the fish in the process.

The idea to modify this weapon came to me when my friend complained about his hand getting tired from swimming around holding the polespear cocked and ready to shoot. 

I decided that the polespear would be better if it had a trigger, and came up with this design:
PoleSpear

Then I built it…

First I took a piece of stainless steel and shaped it into a snug-fitting collar that I attached near the tip of the spear with a spring pin.
PolespearMod

Then I glued together a few pieces of wood (something like teak that I had laying around from old patio furniture), drilled a hole through it (slightly large than the spear shaft), cut it to and arbitrary shape using the bandsaw and affixed a little latch (also made from stainless steel) to hook onto the collar.
PolespearMod

To keep the spear from traveling too far, I added a collar at the base with some soft rubber tubing to act as a cushion when the spear is stopped (I think the piece of rubber is an in-sink garbage disposal adapter).
PolespearMod

To use the spear, I hook the rubber band through the wooden handle, and then slide the handle up the spear till it latches onto the collar at the tip.
PolespearMod

PolespearMod

And then I fired it at a piece of plywood.
PolespearMod

I will hopefully get to use this to kill a fish this weekend, if my son doesn’t disrupt my plans by being born.

Update: I used this over the weekend and probably killed a few fish. I say “probably” because I didn’t actually “catch” any fish.

The rubber band I used is the standard light-duty polespear band, and the added weight/drag of the collar seems to have slowed the spear down just enough to really damage a fish but not actually skewer it. The result is that there are an number of disabled fish hobbling around the waters off the San Diego coast, if they are lucky. The unlucky ones died slowly Saturday morning, trying to figure out why I feebly stabbed them with a dull piece of metal.

The trigger itself worked beautifully, and I’ve ordered a more powerful band that should many little fish fatherless when I next enter the waters.

Lathe Boring Bar Holder

I find boring bars exciting.

I have a boring head for my milling machine, which is excellent (indispensable) for milling holes to a certain diameter in square stock. But for round stock in my lathe I’ve been messing around with various cutters with mixed results while trying to cut the inner diameter of various projects.

Boring bars are the correct tool for the job on a lathe, but I don’t have any. Even if I did, I don’t have a holder.

I decided to rectify this situation by making a holder that would accept the cutters from my boring head set.

When I made my quick-change tool post, I milled a dovetail into a large block of steel. The idea is that I can cut off chunks as needed to make various tool holders without having to mill a new dovetail.

I sliced off a chunk with my portable bandsaw, cleaned up the shavings, and then milled it down to a more appropriate size.
Boring bar holder for lathe
I drilled a starter hole  in one end and through the full length of the workpiece.

Then I used my boring head to bring the diameter to fit the boring bars’ 1/2-inch shanks snugly.
Boring bar holder for lathe
Boring bar holder for lathe

In order to check by progress while boring the hole, I had to move the workpiece out from under the cutter and fit some calipers into the hole. My DRO proved very helpful for this: I could set the axis to 0, move the table to get the workpiece to a measurable location, and then  move it back till the DRO read 0 again. It perfectly relocated the hole under the boring head every time.
Boring bar holder for lathe
Boring bar holder for lathe
Boring bar holder for lathe
Boring bar holder for lathe

Once I had bored out the hole to the proper depth and diameter,
Boring bar holder for lathe

I set the workpiece on its side and drilled 2 holes through to the 1/2-inch hole, which I then tapped out with 1/4-20  threads for set screws (i once again use the DRO to relocate the holes after changing the drill bit out for the thread tap)
IMAG1Boring bar holder for lathe069
Boring bar holder for lathe
Boring bar holder for lathe

In order to tap the threads perfectly straight, I like to lock the tap in the drill chuck, and then use my lathe chuck handle to turn the chuck manually.
Done!
Boring bar holder for lathe
Boring bar holder for lathe

I slapped the new boring bar holder on my lathe and bored out the inside of a couple of my lathe feed gears as an inaugural project. The boring bar performed perfectly in its new holder.
Boring bar holder for lathe

I win.

Cheap DRO! – part 2

Continued from Part 1

With the X-axis DRO installed, I turned my attention to the Y.

The difficulty here was that there weren’t any pre-existing holes or dovetail slots to take advantage of, so it was an entirely custom installation.

The other complication was that the base of the mill flared out to a wider footprint, so the only surface to mount the DRO’s rail on was at an angle relative to the surface on the sliding table itself.

I started by taking off the handwheel on the left side if the table and moving the table all the way to the right to give me working room.
IMAG0966

I then removed the end cap of the table to give just a little more space.
IMAG0967

There was a flat space just under the lead screw that looked like a promising location to mount the measurement unit’s bracket, so I drilled and tapped a 1/4-20 hole in the center of it (approximately).
IMAG0968
IMAG0969

Just then my daughter woke up from her nap, so I put things on hold until the next day.

Since I knew I would be modifying brackets, I started working on the rail so that I would have precise references to work from.

After cutting the rail to length,
IMAG0970

I drilled and tapped a hole near the back of the mill first. I placed it so that the mounting bracket would sit just under the line where the base began top taper outwards, this way I could use the same line near the front to visually confirm the straightness of the rail.

In order to avoid obstructing the full range of motion along the Y axis, I had to modify a couple of the mounting brackets and attach them to the front of the mill, instead of the side. The modification was essentially to attach two brackets together (using one of the spare brackets from the X-axis), so that I could reach the front of the base and still keep the rail parallel to the table.

Now that I had the rail mounted, I could get a feel for what sort of bracket I would need to fabricate to hold the measuring unit to the sliding table.

I’ll gloss over the details, since they aren’t particularly useful), but suffice it to say that I used a vice, drill, hammer, and welder to create the necessary Frankenbracket.
IMAG0971

Since this bracket is always hidden under the table, the install looks pretty good.
IMAG0974

The display units conveniently had magnets on the back, so while a long term setup will be a little cleaner, I was able to stick the displays on the head of the mill for immediate use.
IMAG0972

With the installation complete, I turned my attention to re-mounting the vice on my table.
Because of the location of the travel locks and the dovetail slot, The X-axis measuring unit sits about a millimeter above the surface of the table.

IMAG0978

I always keep my milling vice installed on the table, so I needed a way to avoid the top of the measuring unit.

I could shim up my vice, but that would introduce instability and inaccuracy.
So I marked the bottom of the vice where it crossed the edge of the table.
IMAG0979

Then I clamped a large aluminum bar to the table, parallel to the Y-axis (front/back),
IMAG0980

and then clamped this bar in the upside-down vice (I had to space the vice from the bar with a 3-2-1 block to clear the clamping bolts).
IMAG0981

Then I milled out a swath 1.5 millimeters deep and 1.5 inches wide, starting from the mark I made and cutting towards the back of the vice(away from the jaws).
IMAG0983

This was sufficient to clear the measuring unit.
IMAG0985

I re-aligned the vice and now I’m back in business (figuratively.. I don’t actually have a machining business…)
IMAG0986

So there you have it. $60 and 4 hours later, I have DRO on all 3 axis of my milling machine.
I’ll let you know at some later point in time if it lives up to expectations.

Cheap DRO! – part 1

Cheap DRO!

I bet you never thought you’d read THAT statement!

If you don’t know what a “DRO” is, then you must have REALLY not expected to read it.

A DRO, or Digital ReadOut, is a measurement tool and a display that attaches to each axis of a milling machine or metal lathe and clearly shows the distance traveled during milling operations.

The alternative to a DRO is to count the number of turns and markers on the hand wheel as you make your cuts, but I’m not a very good counter and longer cuts require a lot of turning the wheel (10 turns per inch on my machine). There is very little dispute around the assertion that you should use a DRO if you can.

The problem with DROs is that they are very expensive. It’s not unusual for decent DROs to cost several hundred dollars, and the nice ones are often over $2000. Now, if you’re running a production machine shop, this isn’t a lot more money to add to your capital investments; in fact, your $13000 milling machine probably already has it. But if you’re running machines in your garage as a pass time, it can be tough to justify the extra expense to your wife (unless you commit to an equivalent investment in her pass time, so really the DRO costs double the list price… plus tax).

Enter the Grizzly T23012/T23013 DRO:

T23012 12

I don’t know why it hadn’t occurred to me to look on Grizzly for a cheap DRO; I stumbled across them by accident, browsing the sale items on the Grizzly website.

I had been planning to make my own DRO by modifying a couple cheap digital calipers, but by the time I would have purchased and customize the necessary parts, I would have spent more than the cost of these new.

What’s the catch? These are basically pre-modified cheap digital calipers: they have aluminum slides, plastic housings, and an accuracy certification of +/- .004-inches per 12-inches traveled.

If you can live with this (you can live with this), then these are an amazing deal.

I bought them.
IMAG0951

I ordered a 12-inch one for the Y axis and a 24-inch one for the X. This weekend I installed them.

My mill is the G0704, a BF20 type milling machine. I bought it almost exactly 1 year ago, and I love it.

The first thing I did after taking the DRO out of the package was to install the battery and make sure the thing worked. I started removing the screws around the housing and then realized that the battery could be opened by hand.
IMAG0952
Right… good start.

I installed the batteries (it takes two, and comes with two spares), and turned it on:
IMAG0953

Numbers! okay, on with the rest.

The X axis would be the easier to install, so I started there. I removed the handwheel to get it out of the way for now.

My mill has a dovetail along the length of the front of the table to set stops for left/right cuts.
IMAG0955

I’ve never used the stops, so I re-purposed the slot to mount the brackets for the DRO’s rail and used the threaded holes from the stop itself to mount the actual measuring unit.

I had to cut the rails for the DRO to the proper length, but this was easy with a hacksaw.
IMAG0956

IMAG0957

I had to drill out the rail brackets to fit the screws in the dovetail, but that was also easy enough.

The difficult part here was mounting the measuring unit.

The bracket that came with it was inexplicably designed to hold the unit much further away from the mounting surface than the rail brackets.
IMAG0959

In order to use the bracket, I had to flatten it in my vice, and then shorten it to remove the unnecessary bent metal.
IMAG0960

IMAG0961

As Murphy would have it, I cut the bracket too short, so I had to file a notch in it and clamp it in place using one of the extra stops from the dovetail as a sort of washer.

IMAG0962

IMAG0963

IMAG0964

The washer behind the bracket is my spacer, it keeps the measuring unit perfectly aligned with the rail.

The end result looks cleaner than it is and is actually quite sturdy.

IMAG0965

I ran a the table back and forth a few times to verify that the DRO agreed with my handwheel counting and it did.

One down, one to go…