DIY BHN tester - The build

[kylix.rd]

This is the more detailed information on building a Brinnell Hardness Tester I described in this thread (http://castboolits.gunloads.com/showthread.php?t=168957). There is some welding involved, but not much. If you don't have a welder, I will show you how to clamp it together so you could take it someplace to have a few joints welded. I used a cheap flux-core wire welder. It's not as clean as a MIG, but it gets the job done.

First the materials

3' .125" thick 1.25" angle steel.
3' .125" thick .75" angle steel.
4' .5" square steel tubing
3' .375" round steel rod - Make sure it slides easily into the square steel tubing.
3 .375 OD/.25 ID x 1" steel spacer.
Various lengths 1/4-20 hex bolts with locking nuts. .75" - 2" long

Here's the base pieces cut from the 1.25" and .75" angle steel. The grid should give you and idea of the lengths. The grids are 1" square.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21131515_zpsa707a8e0.jpg

Here's how they go together.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21131534_zps3fe3a4cd.jpg
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21135520_zps95519a25.jpg
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21135536_zpsc6ae2e0b.jpg

Next cut two pieces of the .75" angle steel for the upright.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21141012_zpsbf10c143.jpg

I clamped them together, ground the ends so they're exactly the same length, and then drilled them at once so I know the holes would line up perfectly. Remove the clamp and insert a couple of shorter bolts through the holes and tighten them down to hold them together. Marking about 1" in from the longer end, cut a notch.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21145821_zps99b6e144.jpg

Using a hammer or mallet, bend the metal over to a right angle. I scored the metal right on the inside of the bend as a relief so that the angle could be made sharper.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21150408_zps0e7d1ec1.jpg

Disassemble the uprights and reassemble with the 1" spacers between the lower two holes then drill and attach to the base as shown here.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21153323_zps29dc34bb.jpg
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21153345_zpsaf7e8106.jpg

In the the next post, I'll describe the indentor guide and the lever arm assembly.

[kylix.rd]

Now for the indentor guide. Cut sections of the .5" square tubing and drill the two shorter ones with a .375" hole into which the steel spacers will be fit. Make sure the fit is tight since you don't want them flopping around. If they're tool loose, a small tack-weld will hold them in place. I cut the horizontal supports to a length where the center of the spacers to the center of the vertical support tube was 1.75"
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21160621_zpsda044d6c.jpg

This is where the welding is needed. Clamp things together like this.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21161558_zpsfa61fb16.jpg
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21161618_zpscbef94f1.jpg

If you don't have the ability to weld, just take this whole assembly to a friend or someone that will weld the pieces together. If your local community college has a welding class, you could call the instructor and ask if he/she would be willing to let a student practice. Just take it to the class when they meet and let them do it. Once it is welded, grind it down to smooth it out and remove any spatter or slag. My isn't pretty because of the flux-wire welder, but it is functional. You can also see that the 1" spacers have been inserted into the holes.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21164242_zps0c56f97c.jpg
Here is the guide attached to the upright and base.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21164422_zps8d973ff4.jpg

Next make the indentor rod from a length of the .375" round steel rod. This is the revised rod. The rounded end isn't necessary since that was part of the original design. I'm showing the Rev. A design here. Each hole is .5" apart. Each hole should be large enough for a nail or some other strong steel rod to pass through easily. It should be loose emough to spin easily by hand.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-23202412_zpsa8a87565.jpg

Make sure it is long enough to extend slightly above the top fulcrum. Grind the indentor end flat, mark the center and using a .25" drill, put a small "cup" in the end. This is what will help center the indentor ball.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21172815_zps1f37bf2f.jpg

For the lever rod, you can used what was left over from the indentor support or cut it down to a shorter length. I had the metal from a previous project, so it ended up being about 30". I drilled one end with a .375" hole and inserted a spacer. For this one you do want it loose so that it will easily pivot. I then measured every 5" from the center of the pivot point and cut a shallow notch along the top of the rod. These serve as reference points and to lock in the weight that is hanging so it won't easly slide down the rod. This is the original design of the rod, but it shows the fitment.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-21172224_zpsed3cdb67.jpg

Measure from the center of the pivot on the lever rod to the center of the vertical indentor guide tube (1.75" in my case) and drill a .375" hold that will allow the indentor rod to pass through the lever. This hole needs to be elongated significantly in order to allow the lever to pivot on the indentor rod and not bind. I put the drill into the drill press, grabbed the long end of the lever and held it against the drill and tilted it up and down to work the hole and elongate it.

Now cut a couple lengths of the .75" angle steel and clamp them on either side of the indentor pass through hold. Drill all the way through the angle, the lever rod and the other angle. Do this on both sides of the indentor rod hole and far enough a way to not interfere. This is what it looks like when bolted together.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-23202359_zpse02c408a.jpg

Now drill a hole the same diameter as the ones you drilled into the indentor rod above through the indentor rod pass through hole across to the other side. Here is the relationship between the indentor rod and the lever.

Now assemble it all together and this is what it looks like.
http://i1356.photobucket.com/albums/q730/kylix_rd/2012-10-23202644_zps3decf76e.jpg

You can use the holes in the indentor rod to adjust the lever rod to get it as level as possible for whatever size test material you place under it. You should be able to fit most bullets or ingots under the indentor for testing and have the lever reasonably level.

Refer to my post here for the formulas and directions (http://castboolits.gunloads.com/showthread.php?t=168957) on how to actually use the device and calculate the hardness. This whole project took me about 3 hours on a Saturday afternoon. I took another half hour to revise the lever and indentor. I was getting surprisingly accurate numbers from this device based on the known hardness of the soft lead I used to "calibrate" things.

[I'll Make Mine]

Looks to me as if it would be simpler (assuming access to a welder) to weld up the base and weld on the uprights, rather than drilling and bolting. Minor issue, though, and likely everyone who builds one of these will come up with their own variations.

BTW, for those who don't own a welder, two car batteries, a pair of heavy jumper cables, and an electrode holder (which can come from a scrapped welding cable) can make a perfectly serviceable "stick" or SMAW welder; rod is cheap(ish), and you can "borrow" batteries from working vehicles (you won't damage the batteries if you don't let them get above about 120º F).

[kylix.rd]

Looks to me as if it would be simpler (assuming access to a welder) to weld up the base and weld on the uprights, rather than drilling and bolting. Minor issue, though, and likely everyone who builds one of these will come up with their own variations.

I had started this project with an eye for not having to weld anything. When I got to the indentor support tube, it turned out that welding was going to be faster and stronger than anything else. I also don't have a decent complement of welding clamps and jigs, so aligning and holding the material would have been a challenge. In fact, that big C-clamp and maybe a cheap vice-grip is all I've got :). Of course now that it is bolted together, welding would be much easier yet moot.