Brass Screws for Louise's Inkle Loom

My wife, Louise, likes weaving and quilting. Louise recently purchased an inkle loom, which is one of the simplest types of looms. The one Louise got has two sides, one of them removable. The screws that came with the loom require a screw driver to remove and tighten, so I thought it would be good to create some nice looking brass screws which would be tightened and loosened by hand.

When I started to do this project, I also wanted to check the headstock for alignment with the bed (the Sherline headstock can pivot). The piece of brass that I had to make the screw heads out of was 3/4" in diameter and 5 or 6 inches long. It goes all the to the back of the jaws. I made a few light passes, and after each pass I measured the diameter by the chuck and at the end with my micrometer. Initially, the diameter at the end was 0.005 bigger than at the headstock (i.e. there was a taper of about 0.001 per inch). Since there's a key between the headstock and the bed, rotating the headstock really just amounted to loosening the hold-down screw, applying pressure in the right direction and tightening the hold-down screw. After the third pass, it was within 0.0001. It probably wasn't really that close, as I doubt that I have the "touch" to get tenths measurements reliably, but it was as good as I'm able to do for now.

Inkle Loom

This is Louise's new Inkle Loom. You can see the heads of the existing screws at the very bottom, one in the middle, and one on the right hand side. Bigger...

Ready for Facing

After alignment, I added the steady rest to perform the facing operation. Using the steady rest allowed me to use the piece that I already had chucked up for alignment, and to minimize wastage. Bigger...

Add Chamfer for Knurling

I used the edge of the tool bit to apply a slight chamfer. Bigger...

Knurl

Here's the finished knurl. It's still covered in cutting fluid. Bigger...

Finished Knurl

This is the finished knurl with most of the fluid wiped off. You can see the slurry of cutting fluid with brass bits in it on the knurl (far right). I also labeled the gib, which sticks out enough that I had to move the steady rest over in order to do the knurling. Bigger...

Mess

Here's a closeup of the mess created by the cutting fluid and brass bits. It looks like gold paint. Bigger...

Mess

Another view of the mess. I thoroughly dissassembled, cleaned and re-oiled everything in the knurling attachment. Bigger...

Knurl Closeup

Here's a closeup of the finished knurl. In the picture, I see what might be a few flat spots, which means I probably should have gone a bit deeper. I'll have to check later. Bigger...

Drill Center Hole

I drilled a hole for mounting the threads to the head. I used a #21 (0.159") drill, and used the tailstock handwheel to advance 0.200" (the tip of the drill went in this far). Bigger...

Add Chamfer

I added a chamfer using the edge of the regulat toolbit. Bigger...

Add Second Chamfer

I used a small needle file to add the chamfer to the other side after starting the parting operation. This turned out to be much easier than using the toolbit. Bigger...

Finished Head

Here's the finished screw head. I made the head have a thickness of 0.250" + 0.010" for finishing. I wasn't sure what the finish of the parting operation would look like, which is why I added the 0.010". The first head parted really nicely Bigger...

Weird Parting

The second and subsequent parting operations were anything but pretty. Bigger...

Weird Parting

Here's another view. The parting wasn't straight either. It took me a while to figure out what was happening, and I still don't understand why it happened. As the parting tool was fed into the part, the part was sucked out of the 3-jaw chuck by a small amount. I double checked everything and nothing else was moving. If the parting tool was withdrawn, it no longer lined up with the portion where it started. Fortunately, I added the 0.010 extra! Bigger...

Make washers

After making screw heads from the knurled portion, I decided to make a few washers as well. I found that 0.050" was a nice thickness. 0.040" felt too thin. I drilled out the center portion of the washer using a 0.250" drill bit. Bigger...

Parting the Washer

I decided to use the tailstock to prevent the material from being pulled out of the chuck. It took me until this point to figure out that it was the raw material being pulled out of the 3-jaw chuck. With the tailstock in place, the parting operation was nice and straight. Note that the hole in the end was drilled, not center drilled, so the parting tool won't actually touch the live center. Bigger...

Finished Washer

Here's a picture of the finished washer. I added a slight chamfer to the edges, similar to the head, using a small triangular needle file, while the washer was still spinning on the lathe. Bigger...

Threaded Rod

I cut off a piece of 1/4-20 all-thread, and used a hacksaw to cut slits in two 1/4-20 nuts. I squeezed the nuts using vice grips to ensure a snug fit of the nuts on the all-thread. Bigger...

Ready For Chucking

The nuts need to be about 5/8" from outside to outside in order for the 3 jaw chuck to grip both nuts securely. Bigger...

Turn Down End

With the nuts and all-thread mounted in the chuck, we're ready to turn down 0.200" of the end until it just fits in the head. Notice that the slits in the nuts are between the jaws. When I got within 0.004" of the desired diameter (0.002" of travel remaining on the cross-slide), I started advancing by 0.0005" (which reduces the diameter by 0.001") and checking for fit each time. Bigger...

Setup for Turning Point

The end has been turned down to size, and the head fits over the end. Since a regular drill bit was used to drill the hole, we shape the end to match. I used a drill bit to eyeball the angle. By feeding the toolbit using the cross slide, I got a nice chatter free point. Bigger...

Point Turned

This is the finished point. Since the point of the tool bit is on center, the edge that touches the center of the point will be a bit below center, and the point will have a small flat spot on the end. Bigger...

Check Fit

Here, the knurled bolt head is being checked for fit, and seats fully. Bigger...

Cleanup Thread

I changed the angle to match the 60° thread angle, and cleaned up where the thread meets the sholder. A bit of hand filing completed the cleanup. Bigger...

Cleanup Other End

Leaving the toolbit at the same angle, the piece is swapped end-for-end and the other end is cleaned up. Bigger...

Completed Pieces

Here are the completed pieces ready for assembly. Bigger...

Assembled

I used some Loctite to assemble the pieces. I put a drop of Loctite in head, and placed the bolt into the hole in a swirling motion. I then let it sit for about 6 hours before facing. Bigger...

Holding Fixture

This is the fixture I made for facing the end. I didn't think of using the nuts (with the slits in them), but that probably would have worked just as well. Bigger...

Face Head of Blot

The head of the assembled bolt has been faced (due to the problems created by parting). Bigger...

Original Bolt

Here's a picture of the original bolt on the Inkle Loom. Bigger...

New Bolt

Here's a picture with the new bolt installed. Not only does it look better but it can be installed and removed without a screwdriver. There were two bolts (the middle one is pictured here). Bigger...


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Copyright 2006 by Dave Hylands