Lag in Two-Piece, Two-Bearing Quill

[DLB]

I noted excessive rotational free play, or lag, between the upper auxiliary spindle and the main spindle. Disassembled the headstock expecting to find a worn or cracked spline adapter (aka #57, Drive and Ring) but instead found lag between the two pieces of the Quill Spindle. I found an old thread on the subject, but wanted to start fresh to get the info under Maintenance and Repair: https://shopsmith.com/ss_forum/general- ... -t446.html Summary: the OP had lag and two bad bearings, resolved lag (didn't say how) replaced the bearings, then had excessive noise and vibration and replaced the Quill.

This version two piece spindle has a 3/16 roll pin (aka spring tension pin). I found that the inner shaft (splined end) is a loose fit on a 3/16 drill bit while the outer is a better fit. The lag seems to stem from a poor fit of the inner shaft on the roll pin.

At this point I'm soliciting ideas for resolving the problem short of replacing the Quill. My impression from the referenced thread is that I can expect this to get worse with time and use.

- David

[Hobbyman2]

My end experience was to replace the entire quill set up with a double bearing quill and new bushings from SS and the guess work was eliminated in a reasonable amount of time . not saying you should or shouldn't . if you install a new part into old or a worn part it could work for a while but sooner or later the problem will re-appear .

[DLB]

Thanks. I'm considering the new quill approach if necessary but I will try repair first. I try to support Shopsmith but this is one of those things that aggravate me. There is really no support except at the quill assembly level for even the current production version. Kind of a pricey approach for a relatively high failure item, and I can't rationalize why at least the spindle assembly is not available separately. I have a preference for the two piece spindle where possible because I can do bearing service with tools I already own. Based on what I'm seeing here, I recognize that the two piece spindle would perhaps not be a good choice for a PowerPro but otherwise I'm not seeing much improvement in the new version.

- David

[rpd]

Could you drill a new hole in the spindle at 90 degrees to the over sized hole.

[DLB]

Drilling a new hole or expanding the old hole are probably both possible, I had some reservations about the hardness of the material and weakening the assembly. I found specifications for a 3/16 roll pin indicating a recommended hole size from 0.187" to 0.192". So I expanded it slightly to 0.189 (#12), it was still neither clean nor round. Then I went to 0.191" (#11) and I'm reasonably satisfied with the result. There were only a couple of small places in the bore that this did not cut. I'll order or pick up some new bearings and give it a try.

I'm still very unsure if this is normal wear or indicative of another problem somewhere. Once there is some play in this bore I can see how it expands, but how the wear starts, or if it is a manufacturing thing, is something of a mystery to me.

- David

[DLB]

Installed the new bearings and this is working fine, rotational free play is normal, what I would associate with the spline coupler. There was zero freeplay in the spindle after repair. So the only thing I did was to drill the holes slightly oversize (+0.004") and install a new roll pin, replacing bearings was needed but unrelated to the problem. I still have no clue as to the cause of the oversized or out-of-round hole on the splined portion of the spindle, or how common it is. Just an added note, in his video Jacob Anderson recommends centering the roll pin in the shaft, where the OEM typically inserted the roll pin until it was flush on one side.

- David

[jsburger]

Installed the new bearings and this is working fine, rotational free play is normal, what I would associate with the spline coupler. There was zero freeplay in the spindle after repair. So the only thing I did was to drill the holes slightly oversize (+0.004") and install a new roll pin, replacing bearings was needed but unrelated to the problem. I still have no clue as to the cause of the oversized or out-of-round hole on the splined portion of the spindle, or how common it is. Just an added note, in his video Jacob Anderson recommends centering the roll pin in the shaft, where the OEM typically inserted the roll pin until it was flush on one side.

- David

I think Jacob's recommend is the way I would go for a one off. It seems logical if there is no reason not to do it that way. However, SS may have a fixture to install the roll pin that leaves it flush on one side. I am not sure either way makes a difference in function at the end of the day.

[JPG]

Installed the new bearings and this is working fine, rotational free play is normal, what I would associate with the spline coupler. There was zero freeplay in the spindle after repair. So the only thing I did was to drill the holes slightly oversize (+0.004") and install a new roll pin, replacing bearings was needed but unrelated to the problem. I still have no clue as to the cause of the oversized or out-of-round hole on the splined portion of the spindle, or how common it is. Just an added note, in his video Jacob Anderson recommends centering the roll pin in the shaft, where the OEM typically inserted the roll pin until it was flush on one side.

- David

I think Jacob's recommend is the way I would go for a one off. It seems logical if there is no reason not to do it that way. However, SS may have a fixture to install the roll pin that leaves it flush on one side. I am not sure either way makes a difference in function at the end of the day.

Since tension pins have a sight chamfer on the ends I would not think flush is a good idea.

[jsburger]

Installed the new bearings and this is working fine, rotational free play is normal, what I would associate with the spline coupler. There was zero freeplay in the spindle after repair. So the only thing I did was to drill the holes slightly oversize (+0.004") and install a new roll pin, replacing bearings was needed but unrelated to the problem. I still have no clue as to the cause of the oversized or out-of-round hole on the splined portion of the spindle, or how common it is. Just an added note, in his video Jacob Anderson recommends centering the roll pin in the shaft, where the OEM typically inserted the roll pin until it was flush on one side.

- David

I think Jacob's recommend is the way I would go for a one off. It seems logical if there is no reason not to do it that way. However, SS may have a fixture to install the roll pin that leaves it flush on one side. I am not sure either way makes a difference in function at the end of the day.

Since tension pins have a sight chamfer on the ends I would not think flush is a good idea.

Point taken. Depending on the thickness of the material the pin passes through on the flush side it may not make much of a difference. After all, I assume (yes I know ) SS has been doing it for years with no problem.