Mark VII Speed Control

JPG · Post by **JPG** » Fri Jan 20, 2012 2:56 am

hdoilcan wrote:I heard back from the guy that will be making the speed cams. The price per cam will be $85 + $6.50 shipping (priority with tracking).They will be milled out out aluminum. I would like to get an idea how many to order. Just to be clear I will need the payment before I give him the order as full payment is required at the time of ordering. He said he will start on them as soon as he gets the cam with payment. We will have to give him a couple weeks, so keep that in mind, we wont have them in a couple days type of deal. I will be purchasing a cam this weekend and I will send it out to him on Monday. So as soon as you let me know the better. PM me if you are interested or if you know anyone looking for a new cam.

Do you do paypal?

wannabewoodworker · Post by **wannabewoodworker** » Sun Jan 22, 2012 9:33 am

I would like to get a cam. I would like to wait till you get one back from him to test and make sure it works properly. Let me know how the new cam works out once you receive it please. This is not an easy part to make and really needs to be precise to be functional. I know this based on my experience with the guy I was working with however maybe a really good and talented machinist could make it easily.

gchapman · Post by **gchapman** » Sun Jan 22, 2012 11:42 am

hdoilcan wrote:I heard back from the guy that will be making the speed cams. The price per cam will be $85 + $6.50 shipping (priority with tracking).They will be milled out out aluminum. I would like to get an idea how many to order. Just to be clear I will need the payment before I give him the order as full payment is required at the time of ordering. He said he will start on them as soon as he gets the cam with payment. We will have to give him a couple weeks, so keep that in mind, we wont have them in a couple days type of deal. I will be purchasing a cam this weekend and I will send it out to him on Monday. So as soon as you let me know the better. PM me if you are interested or if you know anyone looking for a new cam.

I am definitely interested in ordering one, but I won't be able to order until after the first of Feb.

Greg

hdoilcan · Post by **hdoilcan** » Mon Jan 23, 2012 5:34 pm

gchapman wrote:I am definitely interested in ordering one, but I won't be able to order until after the first of Feb.

Greg

Greg I sent you a pm. Let me know.

zenman · Post by **zenman** » Tue Jan 24, 2012 7:25 pm

So I was talking o my mechanical friend today. This cam came up in question. I told him that in a device where everything was machined in metal, why would Shopsmith put a Nylon Cam in the speed control. Nylon, which melts at a fairly low temperature.

He suggestions that Shopsmith was either trying to simplify costs with a molded plastic part, which wasn't really the Shopsmith creed in those days, or that in 1967 they wanted to used something that had a low friction coefficient.

Shopsmith wanted this cam to slide inside the follower without a liquid lubrication that would cause sawdust to clump. The speed dial in the Mark VII is actually difficult to turn when there is a rotational resistance as you have to use your fingers WITHOUT any fulcrum or lever. There are even balls there to stop the dial from turning under a load so the fingers have that friction to deal with as well. I think Shopsmith could have milled that cam with steel but chose not to.

Now back to you guys spending $95 on an aluminum CAM. Aluminum might be slicker than steel, but will there be resistance when you turn that dial.

I have a laser cutter, and we are thinking about fabricating one out of delrin which is a heat resilient, slick plastic, but there will be multiple pieces and will look a little different.

Can your aluminum guy carve this cam out of 3/4" thick delrin block?

Here is DXF of our design.

JPG · Post by **JPG** » Tue Jan 24, 2012 8:05 pm

zenman wrote:So I was talking o my mechanical friend today. This cam came up in question. I told him that in a device where everything was machined in metal, why would Shopsmith put a Nylon Cam in the speed control. Nylon, which melts at a fairly low temperature.

He suggestions that Shopsmith was either trying to simplify costs with a molded plastic part, which wasn't really the Shopsmith creed in those days, or that in 1967 they wanted to used something that had a low friction coefficient.

Shopsmith wanted this cam to slide inside the follower without a liquid lubrication that would cause sawdust to clump. The speed dial in the Mark VII is actually difficult to turn when there is a rotational resistance as you have to use your fingers WITHOUT any fulcrum or lever. There are even balls there to stop the dial from turning under a load so the fingers have that friction to deal with as well. I think Shopsmith could have milled that cam with steel but chose not to.

Now back to you guys spending $95 on an aluminum CAM. Aluminum might be slicker than steel, but will there be resistance when you turn that dial.

I have a laser cutter, and we are thinking about fabricating one out of delrin which is a heat resilient, slick plastic, but there will be multiple pieces and will look a little different.

Can your aluminum guy carve this cam out of 3/4" thick delrin block?

Here is DXF of our design.

And what does one use to view a 'DXF" file?:rolleyes:

beeg · Post by **beeg** » Tue Jan 24, 2012 8:36 pm

JPG40504 wrote:And what does one use to view a 'DXF" file?:rolleyes:

AutoCad...

e.friedl · Post by **e.friedl** » Tue Jan 24, 2012 10:09 pm

JPG40504 wrote:And what does one use to view a 'DXF" file?:rolleyes:

Autodesk (the maker of AutoCAD) gives out a free viewer (as do several others)

damagi · Post by **damagi** » Tue Jan 24, 2012 10:34 pm

JPG40504 wrote:And what does one use to view a 'DXF" file?:rolleyes:

You can also import it into sketchup using the import option in the file menu

wannabewoodworker · Post by **wannabewoodworker** » Thu Feb 02, 2012 11:58 pm

I imported into Sketchup 8 Pro and there is only an outline drawing with no 3D profiling??? And the outline has squared corners around the radius. I hope that is because I was looking at it in Sketchup. I think delrin would be a great alternative to the metals and would stay close to the original design idea. As long as delrin can withstand high heat caused by lack of proper maintenance and resultant bearing failure I think it would work fine but i am not familiar with the chemical properties of delrin specifically.