Shopsmith Forums

backhertz wrote:Was just chastising myself on another thread about my 16,000 RPM comment on the idler shaft. I have worked with upper level math most of my working career. So it is not often I make blatant errors.

I just took my calculator out and did the math again and came up with 16,000 RPM on the idler shaft. That is 'assuming' a 1.6: 1 ratio between the idler shaft and the quill assy when spinning at 10,000 RPM.

On the Mark V, the ratio is 1.6: 1 and I assume it is the same on the PowerPro. I read the speed range of the jointer is 3,900 - 6,200 rpm and I know the quill on the Mark V spins at only 5,200 RPM. Those are facts.

So I'm wondering if a PowerPro idler shaft to the drive sleeve assembly is 1.6:1. The PowerPro produces 10,000 RPM quill speed. I wish I had some type of tachometer to measure the idler shaft speed when the quill is spinning at 10,000 RPM.

I just turned on my PowerPro and on the chart it has two speed settings for the jointer: 3,450 & 3,500 RPM. Well those must be quill speeds as the jointer speed range is 3,900 to 6,200 RPM. Assuming a 1.6: 1 ratio, that tells me, I think, the idler shaft is spinning at 5,520-5,600 RPM. Those numbers look good.

Now when the quill is spinning at 10,000 RPM- <aka warp speed>, I am wondering what the idler shaft is turning at. It has to be faster than 10,000 RPM because of the 1.6:1 ratio.

Gentlemen, I believe my 16,000 RPM figure is in fact correct. It has to be. This is good news & I can go back to my meds…:D But I would recommend people use the new plastic shaft guard (521889) to keep anything from hitting the shafts sticking out of the belt cover. They cost only $4 unless you go with a new belt cover that has two threaded holes for the shaft guard screws. It will also protect the idler shaft on a new-design idler shaft assy from being knocked into the headstock.

Please check my figures.

backhertz wrote:The 8,320 is with a Mark V which the idler shaft spins when the quill is turning at 5,200 RPM. Multiply by 1.6= 8,320.

I honestly thought I had confused my numbers. Memory must need some lube…

backhertz wrote:I think I wrote about this in one of the the areas. But I'm wondering if there could be use of 16,000 RPM for a flex shaft or something.