Werowance attempts Upshur Vertical Single

[Cogsy]

The Chuck Fellows method being talked about is the one I use for single cams and it's very easy and fast. For the flank radius, which is determined by the arc the boring head is describing, for smallish cams like these I just set it at around 2" and see how it looks. We're not after maximum theoretical power or anything so I don't think it matters too much.

 

[minh-thanh]

I don't care much about flank radius, I make cam for "approximate " to close and open valve.

 

[werowance]

ok, diameter of base circle is .334 so x that by 2 to get the radius which is .668 then x that by 2 to get twice the size of the radius of the base circle and I get 1.336 so 1.336 would be my flank radius correct? yes I don't mind to experiment but would like to have a close idea of what I need.

 

[awake]

Wait, something doesn't sound quite right. Radius is half the diameter, not the other way around. So, let's assume the radius of the base circle is .334, with a diameter of .668. The flank radius suggested by Stride is 2x the base circle, so a radius of .668 and a diameter of 1.336. Here is a diagram, with the smaller circle represent the base circle (r=.334, d=.668), and the larger circle representing the curve of the flank (r=.668, d=1.336):

Using these circles, we can construct the cam - just have to duplicate and rotate the larger circle to get the desired angle during when we want the cam to act on the valve:

Now we need to find the largest dimension of the cam, i.e., the circle with a radius that represents the lift. In this case, I randomly chose the lift to be .125, so the green circle has radius .334+.125 = .469:

We now have the pieces to draw the basic shape: base circle (radius = .334), flanks (radius = .668), and nose (radius = .469), giving us the super-imposed cyan outline:

But of course, we need to round off the nose so that we don't have the sharp transition between the flank and the nose. So let's take the basic shape and put in the largest circle we can that will be tangent to the flanks and to the nose:

Use this "nose circle" to refine the shape, and now we have our final cam:

 

[Chuck Leininger]

I like your post very much . Thanks !

 

[werowance]

ah ok, yep I went the wrong direction. .334 Is my diameter per the plans so basicly once I convert that all I have to say is .334 radius is my flank size.

.334 diameter divided by 2 = .167 radius but since we are going to double the radius size x2 just skip the division since my plan was already in diameter we are back to.334 but say radius now.

 

[awake]

Yep, there you go. But remember that this is a "rule of thumb," according to Stride. Based on what I was seeing as I was making the diagrams, plus Cogsy's post above, I wonder if this rule of thumb is more towards the lower end of what the radius should be, with room to go much larger.

 

[werowance]

didn't get to try to cut the cams got short on time and honestly still feel a little uneasy doing it. I'm going to watch more videos and read more tutorials until I feel more confident that I do fully understand it.

all the help I have received so far has cleared up many things that I didn't understand before when I was watching the videos and reading the tutorials so hopefully now that I have more understanding of it they will make more sense to me.

I really appreciate all the help given.

but I did get the cam blanks cut (valve and points) - made them from I think tool steel. didn't have any drill rod but I did have an old broken 1/2 breaker bar that's been on my scrap shelf for a while. it cut ok and left a decent finish. spark test showered sparks so its likely high carbon (chamfered the part off edge with my table sander is why the sparks).

and my wife informed me that her fingernail polish remover was 100% acetone and was also nice enough to pick me up a bottle Friday when she was at the grocery store. so now I have a shop bottle of it

 

[awake]

Every man should have some nail polish remover on hand!

I buy mine this way: https://www.lowes.com/pd/Jasco-128-fl-oz-Fast-to-Dissolve-Acetone/50298085

 

[werowance]

and ding ding ding the light went on in my head. watched all the videos and read the tutorials again and it makes good sense to me now.

I want to make up some disks or blanks of the right sizes so I can adjust the boring head a little easier but other thank that I think I get it now.


again thank you all so much for all the explanations. It never would have clicked without them. cant wait to get home to try it now.

 

[minh-thanh]

werowance !
Just a wonder, do you want to do more engine ?
If you want to do more .., make an cam grinder similar as link :
https://www.homemodelenginemachinist.com/threads/simple-cam-grinding-jig.31731/

 

[werowance]

i dont think im up to making a cam grinder just yet.

re-read my plans and description and the jig Mr Upshur called for to cut the cam was 1 inch diameter and says could be larger so that right there tells me now that i understand it that i need to set my boring head for about 1 inch.

now looking at the drawing, it gives an offset for the pin from centerline to be .312 add half the base circle diameter to that and i get .479 x that by 2 i get .958 as the diameter i should set my boring head to cut and i was going to guess at 1 inch after all i read. can anyone check my math to make sure im looking at that right? i know its not critical but still wanted to ask.

 

[Brian Rupnow]

Werowance--When I first started making i.c. engines, I tried the lathe method as described by Mr. Upshur. It may have worked well for him, however I found that it didn't work at all well for me. The method described by Chuck Fellows is much easier and faster. It's a bit hard to get your head around , but when you do it's marvelous. ---Brian

 

[werowance]

Werowance--When I first started making i.c. engines, I tried the lathe method as described by Mr. Upshur. It may have worked well for him, however I found that it didn't work at all well for me. The method described by Chuck Fellows is much easier and faster. It's a bit hard to get your head around , but when you do it's marvelous. ---Brian

Hi Brian really I was just using his method to get the flank radius. I’m setting up to do Mr. Fellows technique but wanted to double check my math

 

[awake]

Weworance, sorry that I didn't have a chance to look at this until now. Yes, I'd say your math is spot on. His diagram suggests .958 diameter for the boring head, close enough to 1" in round figures, particularly since everything above is suggesting that larger is just fine.

The one thing that I don't see in the diagram is the angle of action - is that in the notes somewhere?

 

[werowance]

Weworance, sorry that I didn't have a chance to look at this until now. Yes, I'd say your math is spot on. His diagram suggests .958 diameter for the boring head, close enough to 1" in round figures, particularly since everything above is suggesting that larger is just fine.

The one thing that I don't see in the diagram is the angle of action - is that in the notes somewhere?

Awake, thank you for confirming the math. that makes me feel better. I held off on actually cutting the cam last night wanting to see if my math was right.
I don't see anything about angle of action in the plans.

 

[werowance]

here is the planned setup for me to cut the cams.
I cut 2 disks to use a reference points to set the boring head cutting diameter and the other smaller disk to set the offset of the boring head to reach the base circle diameter. I used a pin in the already reamed center of the cam blank to hold the disks or thick washers if you will in place. I moved the boring head into place until it would just start to drag on a piece of receipt paper (I don't have cigarette papers as most suggest for finding the edge). the receipt paper is thinner than printer paper so I used that. once I had the boring head cutting diameter set to .958 I then switched disks to the smaller one to set the .334 base circle by moving the mill table over until the cutting tip would just start to grab a piece of recipt paper and then locked it all down tight.

I guess I should say that at the start I centered the rotary table to the mill head and then set the .958 cutting size of the boring head and also had the RT rotated until it was on 0 deg with the pointer on the side so I had a good starting reference point.

tonight I cut. I hope anyway.

 

[werowance]

just had time to get started last night. man that first cut I could feel the chatter in my feet. made about 10 more cuts after that and they were fine. giving my RT 1 full crank of the handle for each cut. I hope to get off work early today so I can finish this one up today. but ill have to say its looking just like all the tutorials did so far

 

[awake]

Weworance, I neglected to say that you should work your way down to the base circle in a series of cuts (each of which consists of a series of cuts as the head descends vertically). Once you get to the base circle, then you can turn the RT and the amount being cut is small enough that you can do all further cuts at the base circle setting. If I understand you correctly, you did the first boring cut at the base circle diameter, so you were taking off a relatively large amount - but it looks like you succeeded, so all's well!

What did you decide on the angle of action / lift (or to ask another way, what will be the total amount of rotation used on the RT)?

 

[Ghosty]

I have been doing cams this way for a while, I use a 1.5" dia for the boring head cutting diameter. This is a cam for a twin cam, 4valve head that I have been working on
Cheers
Andrew