Reamer Info

The number one problem call we get from customers is about bushing fitment. The number one cause of these calls is improper reaming. After much research and countless hours on the phone, we've narrowed the problems down to three main causes: drill speed, lubrication, and aluminum buildups.

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1. DRILL speed

Explaining how drill speed affects bore diameter and bushing fitment is really simple. A faster drill makes a larger hole. The larger the bore, the less crush on the bushing. Less bushing crush means that the bushing may install too freely, and that it won't seal as effectively on the servo pin. Conversely, reamer speeds that are too low will make an under-sized bore. Side effects include hard to install bushings and pins that don't slide freely and require much re-sizing.

Ideally, drill speed should not exceed 500 rpm.

We Recommend Tap Magic for Lubrication.

MSC #00261933

800-645-7270

2. LUBRICATION

Lubrication plays a big part in proper bore reaming. Using improper or inadequate lubrication will lead to over-sized bores and excess aluminum build ups on the reamers.

On transmissions that apply through the pin, like the AX4N at left, it's preferable to lube through the apply hole. On transmissions that don't apply through the pin, like the 4F27E at right, apply the lube to the top of the reamer guide.

3. Aluminum BUILD UPS

Aluminum does not dull tool steel. Period. What happens instead is that the reamer collects aluminum on it's cutting edges. This phenomenon is not limited to our products. Check any cutting tool in your shop. These "build ups" of aluminum effectively become the new cutting edges. These build ups obviously do not cut as well as the tool steel and are also larger than the original diameter of the reamer. Translation- a larger bore that was a lot harder to cut.

To combat these build ups, we offer a stone for $17. The stone fits between the flutes of the reamer and cleans the cutting edges up quite nicely. I personally use my stone on my reamers every time I use my tool.
Note: While aluminum will not dull tool steel, bear in mind that cases typically cast from recycled aluminum, which can contain steel. I retired my 9/16" reamer after five years of service when I hit a steel fragment in a 5R55E.

Checking Your Work

We are now starting to offer a set of gauge pins in the size ranges made by our reamers. These pins allow you to check the final diameter of the bore before installing the bushing. They are a great learning tool as they show you how different factors affect bore diameter.

$35.00