Author Topic: The Radial Five (Rudy Kouhoupt)  (Read 89784 times)

Offline Maryak

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #15 on: February 20, 2014, 12:24:02 PM »
Hi Kim,

Good going.

If  may offer a little advice it looks to me that you took bigger cuts towards the finish than you need and maybe you cut it dry, (assuming the tool was on centre and sharp also the speed was a max of 60rpm for steel). Thread finish cuts are around 0.001" - 0.002" just like shaving, you need a good cream, (lubricant) and you don't want any stubble.

Regardless it's heaps better than my 1st effort .

Hope this helps.

Best Regards
Bob
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Online Kim

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #16 on: February 20, 2014, 04:20:36 PM »
If  may offer a little advice it looks to me that you took bigger cuts towards the finish than you need and maybe you cut it dry, (assuming the tool was on centre and sharp also the speed was a max of 60rpm for steel). Thread finish cuts are around 0.001" - 0.002" just like shaving, you need a good cream, (lubricant) and you don't want any stubble.

Hi Bob,
Yes, of course, absolutely!  I always welcome advise!  I NEED the advise!  (as clearly demonstrated :))

My min lathe speed is 70 RPM, which is what I used.  Hopefully, that isn't a big enough difference to cause too much problems.

I was taking maybe 0.010" off per pas to start with, then when it started to look close-ish, I went to 5 thou, I think my last pass was maybe 3 thou.  That may not have been small enough.  Also, the video from Tom's Techniques says to do most of the cutting using the compound slide, then do the last few cuts using just the cross-slide.  His theory is that this will give you better formed threads since for the last few cuts you get both leading and trailing edge cutting.  I did this.  Wonder if that was part of my problem?

I 'think' the tool was on center, but I'll check again, and I think it was pretty sharp.

For cutting fluid, I was squirting on some Viper Venom.  I'd heard it recommended somewhere once, and I just got it when I had an order with Grizzly one time.  But I didn't apply it on every pass.  And I probably should have done more so for the final cuts.

Another thing I noticed - on maybe my second or third pass (very early on) I engaged the half nut at the right spot, but it 'felt' only partly engaged.  And later, it looked like I'd cross threaded things.  Luckly, it turned out that this was early enough along that the mistake was fully removed by subsequent threading passes.  But is there such a thing as a 'half-engaged' half-nut?  Or did I just miss my mark and not realize it?  I was more careful after that to make sure I was very "definite" when engaging the half-nut and didn't seem to have any further issues.

Thank you for taking the time to give me some feedback on my first threading endeavor,
Kim
« Last Edit: February 21, 2014, 03:12:15 AM by krt2 »

Offline Maryak

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #17 on: February 20, 2014, 09:48:08 PM »

His theory is that this will give you better formed threads since for the last few cuts you get both leading and trailing edge cutting.  I did this.  Wonder if that was part of my problem?

Could well be. IMHO the deeper you are into the thread the more the area of the cutting face so the more load on the tool. Cutting on both sides doubles this load and can very easily lead to chatter.

Quote

But is there such a thing as a 'half-engaged' half-nut?


Yes it can be done, especially on an older worn machine . The effect is as you described because the saddle does not start to move until the lead screw takes up the slack in the nut. One way to overcome this, (and the only way to cut metric on imperial and vice versa), is to leave the half nuts engaged throughout the threading process and drive the lathe in reverse to return to the start of the next cut.

Here is an article by Bogstandard on making a swing up threading tool which assists this process tremendously.

http://www.modelenginemaker.com/index.php/topic,858.msg9461.html#msg9461.

Best Regards
Bob

PS When i was taught to thread cut, (about the time Adam played fullback for Jerusalem), I was taught using method 2 in my picture and its the method I normally use.
« Last Edit: February 20, 2014, 09:57:18 PM by Maryak »
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Offline Hugh Currin

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #18 on: February 21, 2014, 01:12:02 AM »
Kim: I use the technique you describe. Feed in with the compound until almost there and then feed the cross slide the last little bit to clean up both sides. The amount taken off with each pass is small though. I start out taking some 5 thousands radial, but move to 2.5 thousands or less after several passes. (I think, I'd have to make a thread to confirm these numbers.) The final cross slide at the end is a few thousands on diameter and maybe a spring cut. I use a lot of lubricant on each pass, don't usually but for threading I flood it.

Bob: That last bit of cross slide feed is a very light cut, just to clean up the following face. I've not had trouble with this aspect. I have a host of other problems with threading, mostly due to stupidity, but this light cross slide feed hasn't yet been added to the list. My biggest problems come from being in a hurry and trying to take too large a cut.

There was an article in Home Shop Machinist a few months ago about threading. The author presented a scheme for optimizing feeds. I think it was based on taking the same volume of material with each in-feed. I haven't used it, it seemed like a lot of calculation. It did give a good idea of the depth of cuts used though. I recommend reading it just for that.

Hugh
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Online Kim

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #19 on: February 21, 2014, 06:05:44 AM »
Thanks Bob and Hugh for the feedback on my threading work.  I always learn so much from you guys! Thanks!

So tonight I had just a short time in the shop and I wanted to get started on the fixture I'll be using to hold the crank case for shaping.  This required a 3/4" wide piece of 3.5" Aluminum.  I got that setup in the saw and let it cut.


I knew this would take a while, but I had NO idea how long!  It took 50 minutes to cut that thing!  Of course, about 1" into the piece the blade snapped.  No biggie, I've had the original blade on there since I got the saw almost 2 years ago.  But I've really only cut small stock up till now.  This was the biggest thing I've ever cut by a long shot!  And no, the 50 minutes didn't include the time it took me to change blades!

So I changed the blade (I had a spare) but it's the same kind of cheap HF blade that came with it.  I know "the best blade to get" topic has come up a lot, so I'll do a search for that and get something better on order.  These cheap blades cut really slowly and if I'm going to be cutting bigger stock like this, I think I want something better.

After 30 min I passed the 1/2 way point and it started going faster.  That middle inch took a long time to cut.


Once I had my disk removed, I put it in the 3 jaw chuck and faced one side.


Having never turned something this big, I learned something new - something I already 'new' but I had to run into it and scratch my head, and then have the 'ah ha' moment.  I was turning the aluminum pretty fast, like I would have a smaller part.  And interestingly (predictably?), as I faced it off, the outer 1/2" to 3/4" had a really ugly finish, tearing badly.  But the inner diameters turned much nicer.  Duh!  The outer diameter has a higher linear speed past the tool.  I slowed the spindle down and got a MUCH better finish all the way across.  Isn't that cool!  I just love it when that theory stuff works in real life and I get to see it happen!  :cartwheel:

OK, that's all for tonight.  I'll finish up the fixture next time.  But I wanted to share my startling revelations with you all! :)

Thanks,
Kim
« Last Edit: July 23, 2017, 04:42:57 PM by Kim »

Online Kim

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #20 on: March 04, 2014, 06:21:24 AM »
It's been a while since I've posted an update!  The last several times I was going to post, my son was using the computer to write term papers.  Figure he has priority! :)  I can read the forum on my Android tablet, but I have a hard time writing any significant post on it!  I really need the full keyboard  :atcomputer:

So, what I have I been up to? Well, to start with, I finished off "Fixture A" as Rudy calls it.

After making my disk nice and flat, off it went to the mill to drill a couple of CS holes for some #10-32 Socket Head Cap Screws.  I made these to line up with holes I'd tapped previously for some other project.  Turns out, those holes weren't very symmetrical.  They're fine, but not uniform.


Mounted the disk to the faceplate with two 10-32 screws and mounted it to my nifty little threaded piece, turned a couple of carefully measured steps into it, then drilled and threaded it 1/4"-20.


There were too more parts to Fixture A - some Caps for holding the Crankcase, and later, the valve housing.  Here I've turned one of the caps (the one for the crankcase) and am just cutting it off.


And here's the whole Fixture A family - the faceplate mount and two end caps to hold various parts during fabrication.


Well, that's it for Fixture A.  Now on to the Crankcase, which will take advantage of this wonderful fixture.

Kim
« Last Edit: July 23, 2017, 04:43:21 PM by Kim »

Online Kim

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #21 on: March 04, 2014, 06:33:09 AM »
The crank case started as a 1" wide slice of 3" aluminum.  I mounted it in the 3-jaw chuck, faced it off, then center drilled it starting at 1/4".  I stepped my way up to 1", which is the largest drill I have - though my >1/2" drills are mighty cheap and aren't very accurately sized and make really ugly holes.  But in this case I didn't care.  I just wanted to get more material out of the way.


After drilling to 1", I picked up with the boring bar:


Question: So, does 6061 always come out this stringy? Maybe I've just never taken so much off before, but this seemed especially stringy, and stuck to the tool a lot.


After I got it close to size (1 5/8") I edged it larger till it just fit the Fixture A cap.  This is the inside of the crankcase, so I don't think the exact dimension is that important, but it is important that it fit snugly on the jig I just made (that would be Fixture A for those of you following along at home)!  And here's my test fit:


With that done, I flipped the part around and mounted it on my 3 1/4" four jaw chuck, holding it on the inside.  I indicated it up so that it turned concentrically, and so that the back (the finished side) turned perpendicular to the lathe axis.  That way, when I faced off the remaining side, it was parallel to the back, and square with the bored hole.


Facing off the part to the correct width went without incident.  And after that, it was time to mount it in Fixture A.  And then mount Fixture A to the Rotary Table on the mill.


With things in this position, I proceeded to use a roughing mill to take the crankcase down to a pentagon.  Here's 3 sides roughed out.


Then I put in a 1/2" (3/8" shank) four flute bit and took off the last few thousandths to bring the crankcase to size.  Boy!  That new end mill really makes a nice clean cut!  Much nicer than the 2 flute I've been using.  That's a nice tool!


With the main shape in order, it's time to put in the little decorative curve between each cylinder flat.  The plans call for a 1/4" radius here. But since I was unable to locate a 1/2" ball end mill with a 3/8" shank (that's all my Taig can hold), I decided to just go with a 3/16" radius.  I think it'll look fine and I'm betting that nobody will notice in the end (except for people who've read this build log!)

But, before I can cut the channels, I have to locate the peak.  I did this with the laser center finder.  It worked quite well!


And it was a simple operation to take the five peaks off with the 3/8" ball end mill.


Next, I found the center of the flats, center marked each one, then drilled them to 3/8".  I was going to do 1/2", but the 1/2" drill won't fit in the collet so I'd have had to use a chuck.  And the chuck plus the 1/2" bit exceeded the Z height I had to work in (yes, even the screw machine length bit wouldn't fit).  So 3/8" it was.  Just made a little more work for the boring head.


And here we are, having bored out five, 5/8" holes for the five cylinders.


It's starting to look like it's going to be a radial folks! :)


That's where I left off tonight.

My next move is the bearing housing on the front side of the crank case, then we'll move to the valve housing on the back.

Thanks for looking in on my build,
Kim
« Last Edit: July 23, 2017, 04:43:52 PM by Kim »

Offline fumopuc

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #22 on: March 04, 2014, 07:10:00 PM »
Hi Kim, that looks good. Always watching.
Kind Regards
Achim

Offline tvoght

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #23 on: March 04, 2014, 07:42:49 PM »
Good writeup and photos, Kim. Looking good!

--Tim

Online sco

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #24 on: March 04, 2014, 08:03:05 PM »
Agreed - that's some slick work!  Keep it up,

Simon.
Ars longa, vita brevis.

Offline Don1966

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #25 on: March 04, 2014, 09:42:58 PM »
Very nice work Kim, your doing great. I believe the reason the material sticks to you cutting tool is because you have a cutter with relief on it. Use a flat cutter with no relief should cut without sticking. I like......... :ThumbsUp:

Don

Online Kim

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #26 on: March 05, 2014, 03:31:32 AM »
Thanks for the comments everyone!

Don, thanks for the pointer on the tool relief.  I'll have to try that!  the boring bar I was using uses a HSS insert, which does have a relief cut in it.  I should have used one of those more basic boring bars like I used in the boring head on the mill!

Kim

Offline Hugh Currin

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #27 on: March 05, 2014, 03:59:18 AM »
Kim:

Great start on the engine, nice work.

Are you using any kind of cutting fluid? It may not help with the stringy chips, but I at least get a better finish with a little. I use a mist coolant, with KoolMist, for heavier cuts. Then many times an A9 cutting fluid for aluminum and Tap Magic for steel. Others probably have better solutions, but these work for me.

I had to mention this because your new lathe just looks too clean :-)

Hugh
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Online Kim

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #28 on: March 05, 2014, 04:22:51 AM »
Thanks Hugh :)

Well, I've been cutting dry.  It seems if I find the right feed & speed, it cuts pretty cleanly, even dry.  Though I do use some WD-40 on aluminum sometimes.  Haven't tried any of the A9, but I've considered it.

I just don't think I'm ready to get into dealing with the coolant spraying around all the time.  And once you get it in the system, you have to keep changing it or it goes rancid, doesn't it?  That's what I remember from my limited experience working in a machine shop (worked there to put myself through college many years back!).  That place always smelled of rancid coolant.  My wife is very understanding, but if the garage started to smell that bad, I think I'd be out of a hobby real quick! :o

Kim

Offline Hugh Currin

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Re: The Radial Five (Rudy Kouhoupt)
« Reply #29 on: March 05, 2014, 04:41:28 AM »
Kim:

My lathe has a built in flood coolant system, but I've never filled it for the reasons you mention, the coolant does go bad. I use a mist coolant which siphons coolant from a small coffee can. If I don't get to the shop for a few weeks the mix in the can does go bad. In that case I just dump it and start over, not a big deal. I move the can between the lathe and mill. The Kool Mist doesn't smell, just gets cloudy and "mossy". (I stop short of recommending mist coolant to others, putting a fog of mist throughout the shop can't be a good health move.) I look forward to progress on the low fog mister, that might be an improvement.

I would suggest trying some lubricant though. I haven't tried WD-40, it might work as well as any. Try a squirt of A9 or Tap Magic and see if those work as well or better. I'm only talking from my limited experience though, your mileage may vary.

Thanks.

Hugh
Hugh

 

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