MTFCA Forum

Hi all,
I'm hoping that someone has a reamer for the brass spindle bushings that I can borrow so that I don't have to purchase one. This may be the only time I do this job. Thanks.
John

John...FWIW...I prefer taking my spindles with the bushings inserted and the bolts to my local engine shop to be honed. I have always been told by people smarter than me that honing is much better than reaming. My guy gets these so "spot on" its not funny. I also believe it gives the bushings a bit longer life. Doesn't cost much, usually $20. Just saying. Ur decision.

Another good reason to join a chapter. Many chapters have tool cribs for loaning or sometimes renting for a small fee that goes to maintain the crib.

The correct line reamer (not a hand reamer pushed in from each end) is an appropriate and adequate tool for the job. If you do the work regularly, it will pay for itself quickly.

On the other hand, if you have ONE to do in your lifetime, then Tim's advice is very good. Take it and have it honed.

My background is as an apprenticed watchmaker, who worked for years in the trade, and then as an Aerospace Engineer working with navigation systems...lapping hardened gas bearings to within 2 millionths round and 5 millionths straight or flat. I have a passing knowledge of making round holes and flat surfaces. With that mentioned, I can say that if you attack these bushings with a Chinese expanding reamer and chop your way through like Paul Bunyan cutting a path for Babe, then the honed option is a vast improvement and will last longer. If you use a proper line-reamer, you will notice "ZERO" difference in ease of steering or longevity of the bushing/kingpin fit.

For those that have ever lapped a previously reamed hole, you have found that the round hole made by the reamer in fact "lines" running down the bore which if indicated on a Form Taly Surf will show the hole to be round with very small, regular excursions outward. A honed hole will be dead, dead, dead round. Why mention this? Well, the reamed hole with the lobed excursions (not measurable with standard instruments) provides a path for the oil to seep past the bushing(s) and lubricate the perimeter. With honing, you can get a perfect sliding fit to the kingpin which, if too close, will not pass oil to the lower bushing until it is already beginning to wear.

Reamed bearings will allow the proper viscosity oil to pass, always. Honed bearings will allow the proper viscosity oil to pass, sometimes.

If you use the proper reamer tool with the facing tool perpendicular to the reamer, you can get the ends to fit properly into the axle. One problem is that after many years of use, the upper ear on the axle gets a groove in it and makes the top and bottom farther apart than stock. So you can re-face the top of the axle and then face the bushing to fit. You could take it to a shop, but you should have the axle with you when you do. Otherwise, you might have to install a washer or something else to fill the space, which is just another thing to wear out your spindle bolts.
Norm

Great idea about the machine shop. I'd rather have a professional do it than myself. I'm not sure the Long Island chapter of the MTFCA exists anymore. Tried contacting them and no response.
John

Thanks Scott for that information.
You will or may have to,still face the bushings for fit.
I can't understand all this worry about making sure the hole is dead round? If it were carrying a shaft that turned, yes. The spindle only turns a few degrees each way.
The bushing I installed in about 2010 on my 21 were still ok when I sold it last year and they were just reamed. While maybe I didn't drive cross country, it did get driven on all the club tours for at least the last 8 years plus a lot of other driving.

If you ream the spindle bushings they need to be In line so I make a tapered sleeve to fit the bushing hole and slip over the shank of the reamer to center the reamer. I ream .0015 thousands under the finished size and run a roller burnisher through to make the material to finished size and it makes the material denser to hold up longer. I have never had to replace any bushings in the last 55 years.