Sunday, November 16, 2014

Crosman 1400 Repair

Sears branded version of the Crosman 1400

A few months back I purchased three vintage airguns for a great price. They were a Sears branded Crosman 600 with the original box and manual, a Daisy 1894 BB gun (the original version, not the re-issue), and this Sears branded Crosman 1400. The 1400 was the only one that worked. I took it out for the first time a few weeks ago and had a blast plinking in my back yard. That is until one of the seals failed and I heard a hiss come from the rifle after I pumped it up. Look like it's time to reseal it. I ordered a reseal kit from Bryan and Associates.

nice walnut stock
someone must have dropped it, the trigger is broken and the guard is bent
much nicer all steel front sight than the 140

I want to give credit to Nick Carter of Another Airgun Blog for the helpful instructions on the tear down. I think this is an early version from the early 1970's as evidenced by the sliding breech cover. The 1400 has a blow off valve meaning that the valve is held closed by the trigger. You cannot over pump this rifle like you can with a hammer-struck valve. It is an upgraded version of the Crosman 140 and the Sears branded version were usually of even higher quality. I thought about a complete restoration but the rifle is in pretty good condition and it is going to be a shooter, not a wall hanger. I'm just going to get it working, clean it up, and go shooting!

stock screw and safety removed
First I removed the stock screw. The entire screw came out instead of just the nut. Then I drifted the the safety out with a punch. Then the action can then be removed from the stock. With the action removed, I wiped the stock down with Formby's Lemon Oil to bring some life back to the dry walnut. That stuff works miracles on old wood.

trigger group removed
looks like heavy corrosion in the trigger group

With the action out, the trigger group is removed. Keep track of the screws, they are not the same. The small one goes in the rear. An offset screwdriver helps here.

pump cup looks good

Next the front roll pin is drifted out with a punch. The end plug and the pump arm are removed from the pump tube. The pump cup looks good and had suction when I removed it. It is a pain to replace so I'm going to leave it unless I have problems.

breech cover removed
rear screw (with spacer) and bolt removed

The sliding breech cover is removed by taking out the one screw. Then the rear screw is removed. It goes though a plastic spacer which must be removed before the rear plug can be removed. One the rear plug is removed, the bolt can be pulled out the back.

breech screw removed

Next the breech screw is removed and the barrel can be removed from the pump tube. At this point the plastic spacer and transfer port can also be separated.

threaded bushing
end plug and hammer pieces

A threaded bushing has to be removed to take the end plug out of the pump tube. I drifted it out from the top with a punch. Note the orientation of the bushing. Then the hammer pieces are removed from the rear. The end plug had a little bit of rust.

orientation of valve parts
valve disassembled

The valve can then be pushed out of the front of the pump tube. The valve is unscrewed to get to the seals and spring. That's it for the disassembly. I cleaned each part with Break Free CLP, wiped them off, then coated them with Crosman Pelgun Oil. I scrubbed any rust with CLP and 0000 steel wool. The white spacer had some rust stains. Simple Green did nothing but CLP and a little elbow grease did the trick. I cleaned the barrel with CLP on a patch and jag. Maybe I'm crazy but it feels as if the barrel might be choked as the patch felt harder to push out of the end.

new seals

Match the new seals with the old. Start by replacing the valve seals. The valve then inserts from the front. Make sure the threaded hole in the valve lines up with the bottom hole in pump tube. The hole in the black part of the valve lines up with the transfer port in the top of the pump tube.

The hammer pieces then install from the rear. The orientation of the rear valve piece is wrong in the picture. The hole should line up with the top hole in the pump tube.

transfer port cutting tool
new transfer port (L) and old (R)
The new transfer port seal in the reseal kit was too short for the 1400. It looks like it was for the 140. The white spacer requires a longer transfer port seal. No worries, I made a new one from 1/4" nylon tubing. I used my transfer port cutting jig to cut the new piece. The tubing is inserted through the 1/4" hole and then a drill bit is inserted inside the tubing. Then a sharp razor blade is used to cut the tubing. The cutting jig ensures the the cuts are square and allows you to cut very small slices from the tubing for an exact fit. I measured the old transfer port seal at 5.26 mm. I cut the new one to 5.30 mm allowing some extra material for compression.

bent trigger housing
1400 trigger group

Now for the trigger group. I had a nice adjustable 160 trigger group that I thought I could swap for the broken trigger. Unfortunately the sears are not the same. Guess I need to fix this one.

removing the dent

I used a piece of aluminum rod and a plastic mallet to tap out the bent trigger guard in my vise. It turned out pretty nice.

lots of corrosion
not bad!

With the bend removed I attacked the corrosion with some CLP and a brass brush. It cleaned right up. I put the trigger group back together, adding some grease on any contact areas.

ready to rock
Lastly, I replaced the pump assembly tapping the roll pin back in. I oiled the pivot pins and greased the high wear areas. Put the action back in the stock and bolted it back together. Time to shoot.

Crosman Premiers at 10 m with 5 pumps

I headed outside on a balmy 48° day and set up my chronograph. Here are the average velocities.

Pumps     Velocity (fps)
  2                 339
  3                 412
  4                 474
  5                 520
  6                 556
  7                 586
  8                 605
  9                 628
  10               639

Ten pumps was tough and only gave a few more fps. I tested the accuracy at 5 and 6 pumps at 10 m with Crosman Premiers and JSB Exact Diablos. The Premiers edged out the Exacts. The best group of 5 was 15/16" with the Premiers at 5 pumps. Given the mediocre sights and my mediocre eyes, I'm pretty pleased. But targets be damned, this gun was made for plinking. I was able to destroy 2" Daisy Shatteblast targets without any problem at over 90 feet once I had a the elevation dialed in. The windage was spot on; pellets smacking the narrow stakes every shot. I think this may become one of my favorite airguns. Real steel, real wood, timeless style. Now to get the rest of those vintage airguns working.

Friday, November 14, 2014


I finally got a 3D printer. Well technically it's not mine, it belongs to my lab. But I have access to it! We decided to purchase one to make custom parts for our hexacopter. We could order a whole bunch of 3D printed parts online for what the printer cost us, but having one in-house allows us to prototype much faster and correct any problems with the designs quickly. Plus it's just fun!

results of Make magazine review

I spent a lot of time selecting which 3D printer to purchase. I finally settled on the Ultimaker 2. It got excellent reviews, print quality appeared excellent, and the machines seemed to have a reputation for working well out of the box without too much fiddling around.

After unboxing I went through the setup process which basically just involves cutting some zip ties, snapping on a few pieces, loading the filament, and leveling the build plate. Most of the setup was pretty easy but leveling the build plate took a few tries. The process is straightforward: raise the plate to about 1 mm from nozzle, put a piece of paper between plate and nozzle, and adjust the leveling screws until you feel a little friction in the paper. The problem was my machine came with the build plate screws almost maxed out to their highest position so that I did not have enough adjustment to raise the plate to the nozzle. Once I realized what was wrong, I cranked the screws to bring the build plate down several millimeters and then repeated the process.

leveling screw

As soon as the build plate was leveled I tried a test print.  The Ultimaker 2 prints directly from an SD card. The card comes preloaded with several models. After telling the printer I was printing in PLA, I selected the UltimakerRobot file and hit print.  About 45 minutes later the print was finished.

first print!

The first print came out pretty nice. The base printed with a major hole which I think is due to a gap in between the old test filament in the machine and the new filament I loaded. No big deal, I should have removed the old filament first. Some of the overhangs are a little messy.  And there are tiny gaps in the layers which may be from slight under extrusion (not enough plastic coming out of nozzle). I'll adjust some settings and try again, but it looks like I'm not too far off from getting some excellent prints.

hole is my fault, not printer error

So far I'm pretty impressed with this machine. I can't wait to get this thing dialed in and start printing some useful stuff. I want to document all of the prints that come out of this machine so I can keep track of the settings and help other people get their UM2's dialed in. I don't want to bog down this blog with boring printer settings so I have started a new blog just for that purpose at Check it out.

Monday, November 3, 2014

Dyeing 3D Prints

dyed parts

Recently I designed some parts and had them printed by Shapeways. For a few dollars more I could have had the parts dyed, but none of the colors piqued my interest. Then I remembered seeing these instructions on how to dye printed parts at home. I figured I would give it a try.

original parts

I checked the Rit website and found a color I liked. I selected "Tender Shoots". Luckily I had both of the base colors already.

color recipe
I started by brushing the parts off then scrubbing them under running water to remove the excess nylon powder. The instructions suggested soaking the parts in water for at least 30 minutes or even overnight. I soaked them for two and a half hours.


Next I boiled some water in a glass measuring cup and added the dye. I didn't need much water so I cut the recipe in half. Unfortunately I messed up and added too much of the aquamarine so the end color was off. The instructions mentioned dyeing the parts for 6 minutes, but after that long my parts were still too light. The Rit instructions said to add vinegar when dyeing nylon so I added about half a cup of white vinegar and brought the solution back to a boil in the microwave. The vinegar must have helped as the parts seemed to get darker almost instantly.

in the dye

I continued stirring and reheating the parts for a total of 25 minutes until the color looked saturated enough. Then I rinsed the parts under hot running water and boiled them in clean water for a final rinse. I let the parts dry then sealed them with polyurethane.

finished parts

The parts look pretty good. The color isn't what I wanted but it's better than plain old white. I think I need to refine my dyeing process a little bit; the color could be more saturated.  Here are a few things I learned and some changes I might make next time.

  1. I am going to try adding the vinegar when I soak the parts before dyeing.  I will also soak the parts for at least 12 hours.
  2. Apparently any acid will help with dyeing nylon. I may try something else like citrus acid to see if it makes a difference.
  3. Fit your parts before you dye them! I forgot to test-fit my parts and I needed to enlarge some holes. That removed dye from some areas. It's mostly hidden on my parts so no big deal, but make sure you make any adjustments first. The dye only goes so deep.

the part in use

Thursday, October 16, 2014

Robot Toy

finished robot

I have been working on a constellation project with my oldest daughter for school. My 6 year old decided she wanted to do a project with me too. She wanted to make a gray robot with eyes that light up when you push a red button on his chest. I asked her to draw the robot so I had an idea of what she was going for.

robot "blueprint"

boxes for the body and head

With blueprint in hand I looked through my collection of junk to find some suitable robot parts.  I found a bunch of small boxes for her to choose from. She selected two gray plastic boxes, a large one for the body and a smaller one for the head. I was going to use two LEDs for the eyes until I found a collection of buttons, lights, and music from an old baby toy I had disassembled. The electronics were powered by three button cell batteries which were just about dead. I can't stand button cells so I pulled a 3 AAA battery pack from a cheap flashlight and wired that in. We then used hot glue to secure the electronics into the body. The button had a flat back and only needed a small hole for the wires to pass through.

electronics in

We tried to drill the 1" holes for the eyes but the box cracked. Luckily I had more. So I used a small tip on my soldering iron and cut out the holes by melting the plastic. That worked pretty well. The eyes were then hot-glued in place. We joined the head to the body with a screw through a short length of 1/2" PVC pipe. The head can swivel left and right.

starting to look like a robot

My daughter adapted the design and decided one antenna was better than two. So we used a length of wire and a bead. For arms we used 3/8" nylon tubing, one piece through the whole body. The fit is tight enough that we didn't need to glue them in. That makes them somewhat poseable as they can rotate around. The boss decided to nix the hands.

arms and antenna

We looked through my junk for some suitable legs. Instead we decided to give her robot wheels. We used two lids from ice cream containers and screwed them to the body. To keep the robot upright, I made a little leg out of a short piece of aluminum tubing with an end cap. I threaded the tube 1/4"-20 and screwed it to the body. Lastly we needed a "smile". It was very important that it was a smile, not your typical robot grille mouth. I found a cable of multi-colored wires that my daughter like so we cut it to length and glued it to the head.


support leg

That left only one thing, the all important button needed to be red. Well she made one more executive decision and decided to go with blue. She colored it with a permanent marker.

robot eyes!

When you push the button, the eyes flash and the robot plays one of about 5 different tunes. She is so proud of her project; she planned a big reveal for the whole family and even brought him into bed with her that night. Can't wait to see what she comes up with next!