Bridgeport Mill Restoration: Part 4 Refinishing the Hardware – Black Oxide surface

I’m skipping ahead in regards to order things happened in the rebuild as many friends are interested in this particular topic and I do not want to write to each of them explaining how it works.

Freshly refinished Turret Bolt in Black Oxide. Contrasts nicely with the Industrial Light Machine Grey Paint.

In addition to restoring the castings and mechanicals on my Bridgeport Milling Machine I scrounged late last year, I needed to restore or replace the hardware. Replacing hardware can get expensive quickly. The hardware on the mill was all very servicable, but very ugly. I opted to clean, polish, and refinish all of the hardware. I am a huge fan of Black Oxide or Blued finishes on steel. While not suitable for exterior applications, this helps keeps hardware used inside from rusting prematurely. Plus, as you see in the photo above, the black hardware contrasts nicely with the Industrial Light Machine Grey paint I used on the castings after stripping them.

degreasing hardware prior to polishing for refinish
Degreasing hardware in a FormWash with Purple Degreaser

Refinishing hardware is a bit labor intensive. Thankfully the Bridgeport uses relatively few nuts, bolts, and washers in assembly. I start hardware restoration by bulk degreasing and washing all of the parts in an old FormWash which agitates the bath and has been modified to heat the de-greaser to better clean components. I use either Simple Green or Castrol Superclean without dilution as a degreaser which works well, especially heated up to about 50C. You can degrease a surprisingly large number of really nasty dirty parts and engine bits in this before you need to change out your degreaser.

The small wire wheel buffer I made from mu parts piles at the start of this project. It’s been priceless in restoring all of the smaller hardware by polishing it to shiny bare metal.

After degreasing, I spend a few minutes on the wire wheel buffer I built polishing the hardware to shiny bare metal. I’m not looking for mirror finish on the parts, but I do ensure no grit, grime, rust, dirt, or burrs remain. I will touch up dings and “Gorilla wrenching” marks with a fine double cut file and rebuff when I find them. I run taps through the nuts to ensure the threads are cleaned out.

polished and wire brushed clean hardware pre black oxide treatment
Post degreasing and wire brush polishing the bolts are shiny bright metal
Furnace oxidation temperature of 300C for black oxide steel
Preheating the furnace to 300C (550-600F) for black oxide coating of steels.

After cleaning and prepping the hardware the next step is to preheat your furnace to 300C. I have a very nice Paragon furnace I scrounged. It was wrecked when I got it due to some experiment gone horribly wrong. I managed to restore and fix this furnace to almost perfect working condition with very little cost. It’s quite large inside and capable of holding temperatures up to about 1100C.

Hardware in the furnace to get black oxide finish restored
Hardware in the furnace turning black.

This is not the modern process of blackening steels that uses salt solution baths. This is more of the DIY, slower old school method. The process involves heating your clean, dry, parts at 300C for an hour or two, then you dunk them in a nice oil. I am a fan of Canola (rapeseed) oil for this dunking. You can repeat these steps if you want a darker heavier finish. This process leaves a nice hard blue-black finish on your steel. The alloy and part size and shape do affect this process a bit. So all of your parts may not end up quite the exact same shade of black. Dwell time and contaminates can cause differences in color as well.

Canola oil for dunking hot steel into in blackening
Use a metal container for your oil bath, 300C steel will melt right through most plastic containers.

I originally saw this process in a video restoration of an old Vise that my buddy Brian shared with me. This is that vice restoration video which is wonderfully put together: https://www.youtube.com/watch?v=U2jNeObHnZY The video is well worth the time to watch as it is very well done.

Finished parts come out very nicely with a hard black oxide coating. They look like new.
There are slight differences in the black levels on different parts. Some due to alloy, and some due to part mass/dwell time I believe. I have not extensively investigated this process and the effect of variables like temperature and time have on the resulting finish.

The newly blacked parts get sprayed with a solvent wash to remove the canola oil residue which might varnish over time. I then liberally coat them with Vactra way oil or a nice 30W motor oil before installing them back into the mill.

You can see the black hardware contrasts and looks great with the light grey paint on the freshly restored castings.

On the mill the freshly blackened hardware looks fantastic. I am glad to share this trick. It is a nice quick way to give old hardware a new fresh look in a restoration. I like that it doesn’t require multiple baths of nasty caustic and salt solutions compared to the modern industrial process of hot or mid temp chemical conversion coating to black oxide.

More hardware in the oven for blackening
Another batch of hardware in the furnace for treatment.

Costume constructions tips for Cosplay: Our 2019 Anime Boston Panel Slides


From 2D to 3D: Manufacturing Techniques For Cosplay panelists from left to right, Brian, Cassie, Zac (thanks me!) and Adrian.

For the second year in a row now, I was a panelist at Anime Boston. Anime Boston is probably the New England area’s biggest Anime Convention with 20-25,000 attendees for the weekend at the Hynes Convention Center in the heart of the city. This was the first year I got to enjoy the event, and I had a blast!

Outline Slide of our panel at 2019 Anime Boston titled:
From 2D to 3D: Manufacturing Techniques For Cosplay [AB2019]

I wanted to put up my slides from this years 2019 Anime Boston Panel. Above is an outline of our slides and presentation. Below is a link to a downloadable PDF of our Panel’s talk titled, ” From 2D to 3D: Manufacturing Techniques For Cosplay [AB2019]” You can find a PDF with all of the useful information we put together for this talk.

A bit about this awesome event along with some photos. I had a great time at Anime Boston, and everyone was very friendly and fun. Highlights of the event for me this year were panels(where you learn things), workshops (where you do or make things), Concerts, Cosplay, and so much more. For your plushie and Gundam model shopping needs you can hit up Artists Alley or The Dealer Room. If it exists, and is related to anime it’s probably for sale in one of these two places.

Definitely one of my favorite Cosplays of the entire event. They rocked this get up!
This crew was awesome, group Inuyasha cosplay
With Brian from our Panel. He has done this awesome IRON MAN CAD and build all on his own. He looks amazing in the suit, the visor is powered up and down, and the reactor and eyes glow.

Sugaring the modern way DIY Maple Syrup Reverse Osmosis (RO) system

A half dozen friends have asked me to share my Maple Sap Reverse Osmosis setup I use sugaring each spring to make delicious Maple Syrup. This year I decided to take some pictures and put a blog post together with relevant information for them. Originally I decided to see how cheaply I could put together a small batch process Reverse Osmosis setup for removing water from the Maple Sap I collected. In this version it has been upgraded with UV Sterilization. I am able to remove about 75% of the water with this set up, which translates to an enormous energy savings versus boiling. The best part about this system, is I set it up on a timer which I let run for the amount of time it takes to reach the maximum concentration of sugar.

I actually worked out the energy costs, and ROI last year but can’t find my notes on it. Here’s some quick calculations to show the value of this system. Sap is 98-97% water, you need to boil off most of that to get syrup which has to be 66+%. The latent Heat of boiling at atmospheric pressure for water is 8133 BTU/GAL if we assume 8.35 LB/GAL and take the steam table value rounded to 974 BTU/LB @ 212°F (100°C). Using this RO system saves about 6100 BTU per gallon of raw sap processed. If you use use propane, that’s equivalent to about 0.28 lbs of Propane burned if you have 100% efficiency (which does not happen in boiling but let’s be generous). Consider it can take up to 40 gallons of sap to make 1 gallon of syrup, you are saving 11.2 lbs of propane fuel which amounts to quite the $$ savings per gallon of syrup.

You can see a process flow diagram of my system outlined in the image below. It consists of an inlet that I move from either fresh sap tank to the filtered concentrate tank depending on if I’m adding more sap or trying to increase the sugar concentration. The inlet passes through a UV sterilization unit with a UVc bulb to kill any bacteria, yeast, etc. The UV sterilizer needs to be in front of the pump as the operating pressure of my system (~80-90psi) is higher than the UV sterilizer housing can handle (60psi max pressure). Priming is a bit of a pain with this set up, but once primed it works well.

Ensure you put your Reverse Osmosis Membrane in correctly. In my housing the membrane installs like this. Also check which of the ports is which in your system

The pump then pushes the liquid through a 1 micron filter column followed by a reverse osmosis membrane before returning the concentrated sap to the concentrate tank. Pure water is the waste in this system. I use it for my humidifiers in the house rather than dump it down the drain or outside. As it is purified water you can drink it, or use it however you would like. It seems a waste to dump it down the drain.

Process Flow Diagram of DIY Reverse Osmosis for batch process of Maple Sap to remove water before boiling it into Syrup

I used the following items from Amazon in building my system. In addition to this list of components I used you will need to source some 1/4″ water line, and 1/4″ push to connect fittings. In addition you will need some buckets, or containers to hold your sap. I keep my purified water for use in my humidifiers. You can run the pure water waste line directly to the drain or outside if you so choose.

Aquatec CDP 8800 high flow Pressure boost pump 8852-2J03-B423 100GPD – 200 GPD RO reverse osmosis booster pump 24VAC 1/4 and 3/8
https://www.amazon.com/gp/product/B00A7ZV2GO/

Geekpure Ultraviolet Light Water Filter– UV Sterlizer Water Purifier (6W (0.5-1GPM)) https://www.amazon.com/gp/product/B07FPGCWQX/

Malida Water Pressure Gauge Stainless For Aquarium Meter 0-1.6MPa 0-220psi Reverse Osmosis System Pump With 1/4 https://www.amazon.com/gp/product/B0124FAV6Q/

Pentek 158117 1/4″ #10 Slim Line Clear Filter Housing https://www.amazon.com/gp/product/B003VT79VA/

Aquaboon 6-Pack of 1 Micron 10″ Sediment Water Filter Replacement Cartridge for Any Standard RO Unit | Whole House Sediment Filtration | Compatible with DuPont WFPFC5002, Pentek DGD series, RFC series https://www.amazon.com/gp/product/B01M0MIPUE/

1/4″High Pressure Needle Valve Thread Female Stainless Steel 316 J13W 160P https://www.amazon.com/gp/product/B00NBI3EEC/

Reverse Osmosis Membrane Housing with 1/4″ Quick-Connect Fittings https://www.amazon.com/gp/product/B00CCMNOSE/

HiKiNS Reverse Osmosis Membrane 100GPD for 5-Stage Home Drinking RO Water Filtration System 1-Pack https://www.amazon.com/gp/product/B0795R3NG3/

Pressure gauge on Maple Sugaring DIY RO system
Close the valve until you have a pressure in your system that is just under the maximum your membrane can handle. This will help push the water molecules through the membrane. You can see when your filter becomes plugged as the pressure drop between the two gauges will increase.

In operation, the input from the raw sap tank, and it all passes through the system at least once before entering into your concentrate storage tank. This filters out any solids on the first pass, and sterilizes the sap with the UV sterilizer. The one needle valve in the system is used for concentrate flow control. Decreasing the flow rate through the valve increases the pressure going into the filter and membrane. The increased pressure drives the water molecules through the membrane further concentrating your sugar solution. You want to run your system a bit below the safe operating pressure for your membrane or other weak link in your system. The concentrate is recycled through the system until pure water no longer drips out of the waste line. I find I can get to ~9-10% sugar content with this system.

DIY Reverse Osmosis for batch process of Maple Sap to remove water before boiling it into Syrup
Priming your system at the start of the season can be messy, especially if you forget to open the valve and bleed your pressure before disconnecting something. Make sure you use your setup somewhere a bit of water on the floor won’t hurt anything.

A quick note note on startup. RO membrane columns come with some preservative. Flush 10-15 gallons of fresh water through your system. Additionally, membranes operate differently at low temperature. So if like me your store your sap in an ice cave you build in a snow pile during the depth of winter, you want to let it come to 50Fish for processing, it will work much better than at 32-45F.

We are using water with electricity, make sure you use a GFCI on your system. My shop doesn’t have one, so I use a GFCI extension cord to ensure any shorting through the water trips the power. Safety is important when playing with AC line voltage. Be safe!

I hope this helps you with your own setup. Remember, you need to keep all these things clean. I wash and dry my system for storage, replacing my filter and column every season.

Building a Gantry Crane lift

While restoring my Bridgeport Series I milling machine I reached a point where I needed a gantry crane to lift off the largest component from the mill. I shopped around online but could not find exactly what I wanted/needed in terms of size and capacity. This unavailability lead to me building one. Building yourself a gantry crane has the big advantage of being exactly the size you need. I wanted mine to be able to lift 2 tons safely, and fit with only an inch or so to spare inside my shop’s ceiling.

Drawing of the upright with dimensions. I used 0.120″ wall square steel tubing for the upright construction.

Harbor Freight does offer a reasonably affordable Gantry Crane. With a 25% off coupon you can get it for just under $600. I went and measured it to see if it would meet my needs. You can see my photos of measurements taken on the HF gantry crane in the gallery below. Turns out it would need a lot of modifications to be useful to me. I decided it wasn’t worth buying it to modify as making one would be less work and less money out of pocket.

After CADing up my proposed design, I went to my favorite steel supply shop Cohen Steel to purchase the necessary materials. All of the upright tubing is 0.120″ wall square tube. I ended up getting a short 4ft cheap W8x13 beam from their drop rack saved myself money. I plan to buy a 9ft beam length in the future to use this gantry crane to lift heavy things into the back of my truck.

CNC machining the mounting threads into the Gantry Crane Top Beam.

I machined the top brackets for the uprights as well as the beam ends on my CNC mill. The beam machining was a bit ridiculous, but I was lazy and this was the easiest way. You can see that most of it is hanging off the CNC mill’s table in the photo above. I had to pull the vise to do the machining.

This is the mounting plate drawing for the top of the uprights.

Above is the drawing for the mounting plate on the top of the upright. It’s certainly possible to make one of these with just a drill press and carefully center punching and laying out the hole locations. I used slots in my design as I will likely use different beam sizes when I go to a longer beam. I wanted to leave some wiggle and adjustment room to make assembly easier. The big hole in the bracket is there for alignment. I plan to weld locating rings or disks onto the ends of the beam to aid in assembly. The design of the upright mount is is such that I can add an extension to raise the beam height in the future if I need an extra few feet. Bolt on extensions are a lot easier than going for a telescoping upright design.

CNC milling the top upright mount brackets to secure the beam in place.

About the only trick I used in this build was tack welding the corners of two 0.25″ thick upright top mounting plates together before machining. Doing both at the same time saves some setup and machining time. If you look carefully you can see the tack welds in the corners. I later rounded the corners by hand and removed the tack welds separating the plates.

There was a lot of cutting on my band saw, grinding with different wheels, and welding to build this, but not a lot of tricks outside of being careful. WIP pics in the gallery below for your viewing pleasure.

When you are working long hard 16 hour days, trying to get a job done in a weekend, you make mistakes. I was working fast, and so focused on getting the base cross piece perfectly square that on the second upright I ended up knocking it off center. Thus the two sides are not exactly the same. In function this doesn’t change much, however it does irk me to have made this mistake in my exhaustion.

My whoops on this project, I didn’t notice it until way too late to fix it. Since it doesn’t affect the performance or use of the gantry crane, I left it to remind myself to be more careful in the future. This upright has the center post off center by about 2 inches.

Below is the picture of the gantry crane set up for the first time. I was pretty excited to get it together. It was late Sunday night and I still had a bunch of welding to do. I did a test fit without the top plate gussets or welds being complete to ensure it was going to work before I finished up the welding.

First test assembly of the Gantry Crane

For now, the uprights have a wheel on only one end. I used wheels from an old 4 ton jack I had scrapped a few years ago. You can see my water jet brackets and a fixed wheel test fit in the photo below. The axle is a piece of 3/4″ steel shaft on the Gantry lift. The screwdriver was just to hold it for photographic purposes. To date I have used my machine skates for the other side of the Gantry crane uprights in order to wheel it about under load. Eventually I’ll mount the spinning caster type wheels that you can barely see in the bottom left of the picture below to the other end of the uprights.

Test fit of the water jet cut brackets for the wheel mount. I designed it so I could tilt the upright and roll it about somewhat easily. Each upright is over 100lbs, not so heavy I can’t carry it around but it’s easier to be able to wheel them around.

For the lifting I have a 1 ton Chain Hoist and a Harbor Freight beam trolley. I regret using the trolley. I will eventually buy or make a static clamp type mount for the chain hoist. It tends to roll when in use, which I don’t like. Alternatively I may just make clamps for the edge of the beam to stop the trolley from rolling.

Beam trolley on the Gantry Crane, in use lifting the knee off the Bridgeport.

The gantry crane lifted the knee off my Bridgeport with ease. It allowed me to remove it safely, lifting it straight up slowly so I could ensure there would be no damage to the precious precision machined surfaces of the ways. You can read more and see photos about this first use of the gantry crane in my previous blog post: Bridgeport Milling machine Restoration: Part 3 Challenges of taking apart the mill

If you end up building a gantry crane and my post was helpful please share a picture of your project in the comments. I would love to see what I might have helped inspire you to build. Cheers!