Why cutting the oil filter open?
It's an standard procedure especially in aircraft or racing engine maintenance. After opening the filter you gain access to the filter material and you can inspect it for any signs of metal pieces/filings and assess internal condition of the engine. If any, the metal particles will be small, that's why it's important to not contaminate the inside of the filter while opening it using i.e. angle grinder.
There are specialized oil filter cutters available on the market but they aren't cheap.
It's quite a simple tool, so I've tried to make one myself.
- MIG welder
- angle grinder
- cutting wheel
- 628 ZZ bearings
- engine valve stems
- piece of small steel tube
- bolts, nuts and washers
- random bits of scrap metal
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Step 1: Support Rollers
Size of the side brackets was precisely eyeballed.
I've used old engine valve stems as bearings axles - they were 8mm in diameter and fit perfectly inside the bearings.
Everything was spaced with thick washers and drilled out nuts.
I've tacked the axles in place and boxed the side brackets.
Step 2: Cutting Arm
Two flat bars create a pivot arm with cutting wheel sandwiched between them.
A threaded rod and butterfly nut is used to press the cutting wheel to the filter.
The spring was used to provide additional tension during cutting.
Step 3: Cutting Wheel
First cutting wheel did not do the job.
It had an integrated bearing, but the angle of the blade (~90 degrees) was too big, it was leaving an indentation instead of cutting the sheet metal.
The second one had narrower blade, it was also a bit bigger so I had to drill new hole for the axle.
Step 4: Final Touches and Testing
I've changed the pivot arm bolt for a longer one and added small piece of steel tube - it made rotating the tool much easier.
It still needs some additional changes like
- handle for easier filter loading - it's hard to grip and compress the spring
- some kind of retention bracket for filter - support rollers and cutting blade are not perfectly in line and at first it cuts a spiral
But it works!