Made a couple of small steel sprockets today on my 1100
Yeah had to help someone out and make sprockets for an old chain drive snow trac machine. It was a real odd-ball casting that wasn't what we would call a "stock" item here. I still have to bore out the 2" hole and attach the freshly made drive hub with a little 309L filler. The sprocket is almost 13" in diameter and is set up for a metric chain spaced similarly to an ANSI #80, but narrower. The original part was missing almost half of it's teeth so I ended up using the scan CAD and then hitting the books to figure out what standard it was produced to nearly 60 years ago before it was completely wore out.
Metrology results and research lead me to a British chain standard that looks to have evolved to an ISO 16B1 classification over the years. Overall it was a fun reverse engineering exercise and I'll post some scan stuff and steel cutting on YouTube at some point next week. It will probably be interesting to some folks that don't normally work in steel because I used some HSM for a lot of it and pushed a 3/8" carbide EM to the operational limit for a few lengthy slot cuts. The load meter was yellow for quite a while with no missed steps thankfully. The base material was 3/4" normalized PVQ ASTM a 516 Grade 70. This material should provide a nice balance of toughness and other physical properties for its use out in the frozen tundra of Alaska (304SS would have been ideal, but over the budget). Fun times and was definitely a change of pace from the Titanium and Stainless Steel work that I normally do here. Due to its size I ended up machining it in halves via a fixture and dowels vs. playing around with my rotary table face plate. I figured that this way would provide more rigidity and it worked quite well.
Re: Made a couple of small steel sprockets today on my 1100
Thanks! They still need some surface tweaking, but I'll wait on that until all the welding is complete and I can verify that the components are still square to one another and the good old surface plate.
Re: Made a couple of small steel sprockets today on my 1100
Tormach ScanCAD. I have a NextEngine 3D scanner here too for organic and surface jobs, but for a job like this the ScanCAD is easier to layout a quick DXF with some physical locates added to verify reality in 2D. If you are trying to interpret design intent the ScanCAD is pretty easy to use and the image quality is awesome for later reference. I've used it for a ton of other projects as well. When coupled with a quality USB microscope you can easily preserve a 70x mosaic of a failure for forensic purposes etc. I actually used it to identify the root cause of a client's molding food product a while back. We dyed and scanned in all the jars and lids taken from swollen spoiled products and compared them to the products that did not fail of the same mold numbers, production dates...etc. There was a noticeable, but extremely small, flash line on the jar's finish that allowed cooling water to get sucked into the packages (bringing yeast and mold with it) after the pasteurization step. It was invisible to the naked eye, but a polarization lens made it obvious. When the defect was present there was a 70% failure rate. Having the images readily zoom worthy on the big screen helped us navigate through the issue with their packaging supplier and took away a LOT of finger pointing. It's certainly a cool and powerful tool to have in the arsenal for the cost.
Re: Made a couple of small steel sprockets today on my 1100
Thanks guys! This picture is from the Identification exercise I went through. The red contours are from the DXF generated using Tormach's ScanCad. The Blue Contours were drawings I made using the ISO standard for 16B1. Doing work like this is a lot like playing CSI, but easier because it typically doesn't stink as bad LOL.
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Made a couple of small steel sprockets today on my 1100
like this is a lot like playing CSI, but easier because it typically doesn't stink as bad LOL.
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