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🔧 Technical Drilling out Polyurethane Bushings?

barkingspud

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Nov 15, 2006
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Anyone have a setup like this vid? I need 8 Poly bushings drilled out. I've tried using a drill press but don't have the right clamping setup.



Bushings in question are 3"diameter and need a final ID of just shy of 1" as the sleeve is 1" and it's an interference fit.

BMR Mushings.png
 

🤖 TCG Mechanic Bot

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Dec 5, 2023
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Drilling out polyurethane bushings, especially those with diameters as sizable as 3 inches, can indeed be a challenging task. Using a drill press is generally the most recommended method, however, the right clamp setup is crucial.

Unfortunately, your shared URL doesn’t unfurl properly so it’s difficult to comment specifically on that setup. However, here are some general guidelines for a typical setup that may help.

Generic Setup for Drilling Polyurethane Bushings:

1. **Clamp Setup**: To secure the bushing while drilling, a well-built clamp setup is required. Use a bench vise or C-clamps, securing the bushing between two pieces of flat wood or metal. The wood or metal will help distribute the clamping force and prevent the bushing from being deformed under pressure.

2. **Drill Bit**: Use a hole saw bit or Forstner bit that is just smaller than your desired final diameter. These types of drill bits make a cleaner cut in the polyurethane, reducing the risk of tearing the material.

3. **Progressive Drilling**: Start drilling with a smaller diameter bit to create the pilot hole, then increase to larger sizes progressively. This makes the drilling process easier and reduces the risk of the material slipping on the bit.

4. **Use of Lubricants**: Polyurethane is a material prone to melting and smear due to heat generation during the drilling process. Using a lubricant such as WD-40, can help cut down the heat and prevent the drill bit from heating up excessively.

5. **Respect Speeds**: Don’t force the drill. Maintain a slow, steady drilling speed to avoid excessive heat buildup or tearing the polyurethane.

Finally, since you mentioned you need a final ID of just shy of 1 inch for a 1 inch sleeve, I assume you want a snug fit. After drilling, you can refine the inner diameter with sandpaper until the sleeve fits just right.

Remember that personal protective equipment (especially safety glasses and gloves) are imperative while performing any sort of drilling operations.

However, if the bushings are significantly hard or this method still doesn’t work for your needs, you might consider seeking a machine shop's aid to ensure precision.
 

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