Thinking of building my own power stand for my SS jointer

[bffulgham]

I was sorting out junk this last weekend and came across a 1.5HP 3450 RPM electric motor....used to be a pump for an above-ground pool. To make a long story short, I'm visualizing a power stand for my jointer. I need a little assistance from you folks to check my data.

Here's 2 things where I need some double-checking:

1. I'd like to verify that the desired operating RPM for the jointer is 5000 RPM? (I'm 100 miles from my manuals).

2. If my motor is 3450 RPM and I need to get 5000 RPM:
Motor pulley diameter: 4"
Jointer pulley diameter: 2.75"
(I've got an Excel spreadsheet that does the computation if anyone is interested. If my physics and math are correct, this combination should give 5018.182RPM, but close enough;) )

Thanks in advance! I really enjoy keeping up with the posts on this forum.

Bud F.

[billmayo]

The joiner might leave small ridges at 5000 RPM. The idler shaft (8300) turns at around 1.6 times the quill shaft (5200). The joiner is operated from the idler shaft. The bearings on the joiner cutter head should support 10,000 RPM as I believe the faster the cutter head turns, the smoother it cuts. The thickness planer is a good example. Shopsmith came out with an upgrade kit to increase the RPM of the cutter head from 3450 to 5750. All the later stand-alone thickness planers came with this upgrade.

[quote="bffulgham"]I was sorting out junk this last weekend and came across a 1.5HP 3450 RPM electric motor....used to be a pump for an above-ground pool. To make a long story short, I'm visualizing a power stand for my jointer. I need a little assistance from you folks to check my data.

Here's 2 things where I need some double-checking:

1. I'd like to verify that the desired operating RPM for the jointer is 5000 RPM? (I'm 100 miles from my manuals).

2. If my motor is 3450 RPM and I need to get 5000 RPM:
Motor pulley diameter: 4"
Jointer pulley diameter: 2.75"
(I've got an Excel spreadsheet that does the computation if anyone is interested. If my physics and math are correct, this combination should give 5018.182RPM, but close enough]

[bffulgham]

Thanks, Bill.

I agree with your observations on 'leaving ridges'.

So, If I shoot for 10,000 RPM at the Jointer, it looks like I should look at a 6" motor pulley and a 2" Jointer pulley..... approx 10,300 RPM.

[lv2wdwrk]

The joiner might leave small ridges at 5000 RPM. The idler shaft (8300) turns at around 1.6 times the quill shaft (5200). The joiner is operated from the idler shaft. The bearings on the joiner cutter head should support 10,000 RPM as I believe the faster the cutter head turns, the smoother it cuts. The thickness planer is a good example. Shopsmith came out with an upgrade kit to increase the RPM of the cutter head from 3450 to 5750. All the later stand-alone thickness planers came with this upgrade.

Shopsmith description of its power stand kits states the following:

These kits produce the following speeds for each tool:

Bandsaw -- 700 to 1150 rpm
Planer -- 5750 rpm
Belt Sander -- 1150 to 1725 rpm
Strip Sander -- 1150 to 1725 rpm
Jointer -- 3900 rpm

I have the one for the jointer. Should I consider changing pulleys to get higher speeds?

[SDSSmith]

Based on the following Shopsmith webpage, the recommended speed range for the jointer is 3900 to 6200 RPM.

http://www.shopsmith.com/ownersite/catalog/jointer.htm

[billmayo]

Shopsmith description of its power stand kits states the following:

These kits produce the following speeds for each tool:

Bandsaw -- 700 to 1150 rpm
Planer -- 5750 rpm
Belt Sander -- 1150 to 1725 rpm
Strip Sander -- 1150 to 1725 rpm
Jointer -- 3900 rpm

I have the one for the jointer. Should I consider changing pulleys to get higher speeds?

No, if it is working OK for you. I can only state my opinion of what I have seen and done. Many times I am different from the Shopsmith recommendations and should have stated that when I responded. Thanks for reminding me.

[heathicus]

So how does cutting faster equal cutting smoother? What is the reasoning behind a planer or jointer needing to cut so fast? Hand planes, chisels, and other blades don't have to move so fast to cut smooth. Wouldn't feed rate relative to the RPM of the jointer's cutter head have a bigger impact on the smoothness of cut rather than just RPM alone?

[bffulgham]

Thanks to all for the responses.

Heath, I think I can answer your question. Handplanes and jointers (all rotary cutting tools, actually) work differently. Handplanes cut in a flat 'plane'. Rotary tools cut in an arc. So, with a rotary tool, the smoothness of the cut is going to depend on how close the cuts are spaced apart. Yes, the smoothness of the cut for a jointer/rotary tool is a function of feed rate and cutter head rpm.

[heathicus]

That makes sense. Thanks.

[billmayo]

So how does cutting faster equal cutting smoother? What is the reasoning behind a planer or jointer needing to cut so fast? Hand planes, chisels, and other blades don't have to move so fast to cut smooth. Wouldn't feed rate relative to the RPM of the jointer's cutter head have a bigger impact on the smoothness of cut rather than just RPM alone?

I find most of my customers feed the wood too fast (must get it done now) across the cutter head. If you really take your time, almost any cutter head speed will work. So I increased the RPM of the cutter head so they can do it quicker, be happy and not complain.

I use higher rated RPM cutter head bearings when rebuilding any joiner. Most of my personal headstocks can operate the quill at 6000+ RPM when using the joiner (9600 RPM) as I am guilty of feeding the wood faster too.