Machsupport Forum
General CNC Chat => Show"N"Tell ( What you have made with your CNC machine.) => Topic started by: N4NV on February 23, 2009, 02:46:03 PM
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I have been posting in another section that was not quite the right topic so I am picking it up here. I have been working on a Miser Stirling engine. Most of the hard to make steel parts are done. Today I made a connecting rod end. I made everything on my converted Hardinge CHNC and converted Yamazen mill except for drilling the connecting rod end. It required a .020" drill for an oil hole. I did not have anything on my CHNC small enough to hold the rod end or the drill. I moved it to my watch lathe. The .020" drill is still 5 sizes larger than my smallest collet, which is .010".
(the picture of the finished miser is just to show what it will look like, I have a ways to go).
Vince
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Very nice Vince !
Thanks for posting,
RC
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That is just plain neat Vince. Looks good. :)
Brett
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Super job there Vince.
When do you find the time ?
Ed
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Super job there Vince.
When do you find the time ?
Ed
Unfortunately, I am on a reduced work week, I'm down to 1 day a week. The company I work for is up for sale. If is sells, I should get back to full time, if not, I start looking for work. I should know in a couple of weeks. (I sold over $1,000 worth of stuff from my garage on eBay in the last month to pay for my projects). I am trying to make one part a day. I am also trying to work on my lathe and mill. I need to add the smooth stepper to my lathe and I am going to change the BOB and speed control on my mill (I ordered all that stuff before the work slow down). Then I have to move my MPG to a modbus board so I can get some more inputs for my probe. It never seems to end, but since it's my hoby, I don't know what I would do if it did end. I just ordered a bunch of parts to convert my watch lathe to CNC. That would make 3 CNC lathes and 2 CNC mills at my house. I guess you just can't have too many.
Vince
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Vince,
sounds like you got enough equipment to start your own shop. Do you have a Yamazen mill also?
How did you make out with the cribbage board?
Ed
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Vince,
sounds like you got enough equipment to start your own shop. Do you have a Yamazen mill also?
How did you make out with the cribbage board?
Ed
Yes, I have a Yamazen. I wrote up the conversion here:
http://www.cnczone.com/forums/showthread.php?t=31601
I am still working on the G-code for the board. I was trying to use LazyCam to generate the code. I spent a couple of days hitting my head against the wall because LazyCam would not put any of the holes in a decent order. I found out I had an older version. When I downloaded the newer version it worked. I may look into finding someone around here with a router table that is 4x4 to do all the drilling. I think I could do it on my Yamazen, but it would take at least two set ups and I would have to take the enclosure off that I installed to keep the coolant neater.
Vince
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I finished the rough draft of the G-code for the cribbage board. I used the default feed rates for my mill and the cycle time for the entire board would be 3 hours. There are 1434 lines of code. If I were to use a router table I'm sure the time could be cut to under an hour.
Vince
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Vince,
Did you check out my Yamazen enclosure in my photobucket links.
The doors and the end panels are removable. No tools required. :D
Is your Yamazen running on Mach?
Ed
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Vince,
Did you check out my Yamazen enclosure in my photobucket links.
The doors and the end panels are removable. No tools required. :D
Is your Yamazen running on Mach?
Ed
I guess you didn't see the link above. Yes, it is running on Mach. I kept the Servo Dynamics drives and fed them with Pixie cards. I now can get 450 IPM rapids. With the original AB control system I was limited to 100 IPM.
I thought about building an enclosure like you have, but I could not figure out how to seal the bottom and still have the knee move up and down. I am changing from a water soluble coolant to an oil based one because of rusting so I think I will have to close it up even better than it is now. Do you have any pictures of the bottom of your enclosure? It looks like you installed a separate support structure for it.
Vince
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Vince,
Its only supported in the front. The front panel is .250 Alum plate. The bottom is tapered in about an inch above the base.
the bottom is attached to the back panels and the front panel which has the legs. I wanted enough room under to shove my shop vac and 5 gal pails out of the way.
ED
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Hi Vince,
Sorry to hear about the work slow down. Very nice sterling you are making there.
Tweakie.
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I been sitting around with a cold but decided to work in the garage anyway. I made up the balance disk. There is a small hole that is .7" deep that needs to be tapped 2-56. My 2-56 tap is about 5 threads short. I will have to go to the tool supply shop and see if I can get a longer one.
Vince
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Vince,
Nice going on the Miser. Surely gets the mind off of other things.
RICH
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Vince,
As the hole is for a grub screw couldn't the hole be counter bored, say,the diameter of the tap shank then only tapped for the length of the grub screw ?. This could save the expense of buying a special, long tap.
Tweakie.
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................and the likelihood of breaking it off (if I were to try it). ::)
RC
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I thought about counter boring. The tap shaft is .140" and the part is .250 thick. That would leave me .055" for a wall thickness, which probably wouldn't matter. I don't have a mill that size, I would have to do it with a drill. In the instructions supplied by Howell, he does not mention counter boring so I am assuming there is a tap out there that can do it.
Vince
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Vince,
Another option you might use is to just tap the first portion of the hole, then insert a brass plug under the set-screw to clamp against the shaft. Also prevents the screw from marring the shaft.
RC
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I thought about that as well. That is how most of the set screws on my Hardinge CHNC are set up.
Vince
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I got two days work, Thursday and Friday so I won't get anything done until the weekend. I did stop by the tool store and it seems no one makes a pulley tap in 2-56 threads so it looks like I will counter bore.
Vince
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Vince,
grind some clearence on the shank behind the threads, but first run the tap as far as it will go, then grind and go easy.
I've done this a few times.
ED
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I am just getting over the worst cold of my life. I have only had about 5 colds in my life so I feel real sorry for those who get them. On Friday I actually had water squirt out of my right eye far enough to hit the inside of my glasses. Of course I finally got some work on Thursday and Friday, where I spent the time in jail (I was working on an electrical project in the jail facility). I managed to suffer through it, but spent the rest of the time in bed sleeping.
Today I got a chance to counter bore the balance disk. I went down .25". It looks good. The tap came through the hole to the center. At no point did I feel like the tap was going to break. A 6-32 tap feels a lot worse. I took it slow and only rotated 90 degrees before backing up 180 degrees. On to the next part.
Vince
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I spent 3 hours making another part. If I had an automatic tool changer and I knew what I was doing, it would have taken 10 minutes. This part is called a crank arm. The part was pretty simple to program and make, but my trouble was parting the piece off the bar stock. The first one I destroyed in my lathe with improperly adjusted parting tool. The second one I crushed in my mill trying to mill off the back of the part. I finally found a .020" slitting saw that I was able to use the cut the part off. The part is made from 1/2" steel drill rod.
The larger hole was reamed to 5/32". The smaller hole is drilled and tapped 0-80. I was not able to get a pilot hole for the .046" drill ( it was too close to the boss) so I just took it easy and peck drilled it .020" at a time. I tapped it by hand, I was only comfortable turning the tap 45 degrees before backing it off and clearing the chip. I did not break a tap though.
I am not a machinist by trade and these little projects are teaching me a lot. I'm sure by the time I die I will know about 25% of what I need to.
Vince
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Vince,
Looks like your doing a good job . Myself , I'd rather work on big stuff.
Yesterday had to make repair parts for a Manitowoc Crane.
Ed
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I know what you mean, I like working on the big stuff at work, when someone else is paying for the material. I started on machining when I purchased a watch lathe to fix pocket watches. I have gone full circle. I went to a Bridgeport to a 4,500 pound Yamazen knee mill, to a 5,000 pound CHNC, down to a taig lathe, and now I am getting the parts together to convert my watch lathe to CNC.
Vince
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I have not finished any more parts as I have been trying to fix an out of true chuck. I was finally successful. Now maybe I can move ahead.
http://www.practicalmachinist.com/vb/showthread.php?t=175951
Vince
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I finished the top and bottom displacer plates. What a pain. I still have not figure out a good way to hold a piece of sheet metal (the plates are only 1/8" thick) while trying to machine out a circle. I clamped a piece of wood to the top of my vice and used sheet metal screws to hold down the sheet metal. Even so, it moved one time and I had to set it all up again. The bottom plate does not have any holes in it large enough to screw it to the wood. There are twenty four 0-80 screws that hold the top and bottom plate to the Delrin columns.
Vince
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Vince,
Very nice job your doing.
Sometimes , I mill around half way , and clamp where you just machined , and move clamps till your done. I just use feed hold, and move clamps. CAREFULLY.
Ed
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Vince,
To hold a piece of thin metal there are a few tricks that you can do.
Double backed carpet tape will hold it to a flat piece of wood or sacrificial plate. Another way is expoy
glue it to the plate ( Dabs and use a little heat to soften up the epxoy). Just need to be carefull
when removing the thin plate from the other. Very light cuts also.
Works for me,
RICH
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BTW, If your so inclinded, there are postings which analyze the thermodynamics of the miser.
The analyzation was at a rather high level if memory serves me. Some college posted it.
Just adds another dimension to a project.
RICH
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I think I set a record today for the most hours spent for a part so small. It is the same diameter as a quarter. I must have spent a total of 5 hours. Most of that time was spent configuring my lathe tool table again, and again. But I found the problem that has been causing me so much grief. I was using a .004" feeler gauge for setting my tool positions. Today I noticed something funny about it and looked closer and found a .005" feeler gauge stuck to the back of the .004". So all this time my setting have been off by .01" (twice the .005"). With all my prior pieces I was having a heck of a time getting the dimensions to come out correct. I kept adjusting my tool table. Now, after making the tool table adjustments again with the proper value, my part came out +.001" on the first try.
Another problem I had was I broke my parting tool with a rapid. I have been having trouble fining a parting tool that works with my 3/8" tooling the CHNC requires. I decided to ground down a 1/2" blade that was .0625" too tall. That took about another hour to get it right. In the end it worked well.
The part in the picture is the Crank Disk. It has a 0-80 thread tapped in the small hole. It required a .020" slot across the flange to allow a press fit. I did not have anything that small that I could machine so I cut it by hand with a .015" wide jewelers saw. I made it through without breaking the blade. The time spent on the part included programming. For the first time I used a G96 (constant surface speed) with a G95 (feed per revolution). It worked out very well and cut the time machining the part in half. I won't go into the first attempt I made that I had to scrap because I read the dimensions wrong.
Yesterday I made another connecting rod end that looks very much like the one shown previously.
Vince
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Hey Vince,
Looks good. As far as time goes, for every part i just allow 2 hours. Even what seems simple
turns into two hours. But you got to admit, if you screw it up it's only a penny in material,
and wiith CNC you can make another bad one just like the first one.
Additionaly it keeps ya out of the bar! ;)
RICH
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wiith CNC you can make another bad one just like the first one.
RICH
That is something I like about CNC. When I am all done, I could make another one in about 1/5 the time. All the bugs are worked out and it is almost just loading stock.
I attached a couple more pictures to show where I am at. The flywheel will be the next big challenge. It will take a couple of hours just to program it. I think I only have enough stock for one so I have to make it right the first time.
Vince
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I got 6 hours work on Thursday and another 6 hours today. It will help with the mortgage, but it cuts into my projects time ;-) I have been told that if the company I work for does not sell by Wednesday, I will be laid off permanently. At least now I know where I stand.
I made a part in under 2 hours!!! Just barely. It is made from Delrin. Drilling on my lathe takes a little more time because I have to zero the center drill, then zero the drill. After the lathe work I had to transfer it to the mill in a collet to machine the flats and cross drill. I dream about building a small milling head I can mount to my lathe turret so I can do all of this in one go.
Vince
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I wish you good fortune with the job prospects.
Engine looking good.
Tweakie.
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The project is looking very good Vince. You should be proud. :)
Good luck with your job. I really hope things will level out for you in that department soon.
Brett
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I got a little time today to make another part. This one was one of the hardest so far and more than two hours. I was able to use my cheap indexer to rotate the part to turn the .110" shaft with an end mill. I did some finish work on it with my watch lathe. The fork actually has a .311" radius so it can fit into the cross head guide.
Vince
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Hi, Vince
Nice work, Won't be long now.
Chip
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I made two parts today, spent over 6 hours machining. The big part was the flywheel. The little part was a piston insert. The flywheel took almost 3 hours of machining due to the number of times I had to turn it over and machine the other side, plus I don't have my flood coolant working right now and was limited to about 3 IPM on the feed. There was a lot of inches to machine. I had to write seven programs to cut the part, more if you count the bolt pattern for the hold down screws. It came out perfect. My 3/16" ball end mill finished so close to the spoke recess you can't even see a machining line. I did find out that my crank pin is not true enough and there is a slight wobble in the flywheel. I will have to make the crank pin again. This time I will make most of it on the lathe.
Vince
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I made a couple of crank pins today, .080" diameter with a .053" hole through the center and a .187" flange at the end. I wrote the program and ran it on faith. The cutter looked so big (a 1/4" insert), the part so small and the coolant running made it impossible to see exactly what was happening. It all worked out. I did have some trouble finding the part after I cut it off, then I dropped one of them twice. I finally put them on a piece of 18 gauge wire so I would not loose them. The third part on the wire is the piston insert I made yesterday. That's a penny in the picture.
Vince
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Gees Vince,
At the rate your going, you'll be ready for a smaller version of the miser.
Hope you don't get much time off work as this stuff can become addictive.
I was just laid off twice in three and half days! Same employer! Same manager!
Beat that and I'll send ya a smiley in the next post!
RICH
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Today was my first day of official unemployment. The company I worked for did not sell so they shut the doors. I signed up at the union hall today and there were 300 others ahead of me on the list. We have been getting about one job call a day. Things should pick up in a couple of months. I still have a few calls to make to see if I can rustle up something.
I made the graphite piston today. It machines very easy and I did not break it. It took me about 2 hours to get the fit between the piston and cylinder just right. The clearance is supposed to be .0003". There is an aluminum insert that goes into the piston that attaches to the connecting rod. The hole in the bottom of the piston is for the screw to attached the insert. I have two more parts to make which shouldn't take too long. Then it's put it together and work out the bugs. I promised my wife I would work on her car tomorrow and that will take most of the day. I have to replace the front crank seal.
Vince
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pfffftttt.....That seal can wait. If you replace the seal, then you'll hafta start changing the oil every 10,000 miles or something like that. Right now, all ya gotta do is add a lil bit of fresh oil every so often. Women....they just don't understand mechanical stuff.
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Well, I screwed up the crank seal replacement, or at least the timing belt replacement (the timing belt had to come off to get to the crank seal). I'm just a little off because the car won't start. I gave up about 5 last night and will work on it some more today.
I needed something positive to work on so I finished the last two parts of the miser engine, then spent until 11:00PM last night putting it together. I had several spots where is was binding that needed to be cleaned up. This morning I attached the displacer disc. I still have a lot of friction I need to trace down. I may need to make a part from graphite instead of Delrin. It will not run on the heat of my hand, but it will run on a hot cup of coffee. See the video link:
http://www.youtube.com/watch?v=vdBYzzhe_To
I'm thinking if I let it run for a while on a heat source it may loosen up a bit.
Vince
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Brilliant Vince. :)
I think that letting it run a while will free everything up OK.
Tweakie.
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Very good vince. :)
Brett
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Vince,
your doing a super job on the Miser,
Now , your wife's car . DON'T TURN THE CRANK OVER with the belt off, you'll bend some valves. >:(
This is very critical on overhead cam motors.
Ed
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If all goes well I should start a new job on Tuesday. On our union dispatch books, there is a 6 month wait for a job. Luckily I have "special skills" and will be able to be dispatched directly to a job that needs them. I'm glad to be working again, but just as glad I was able to spend so much time on my Miser engine.
Vince
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Good for you and wish you luck Vince. We are not ready to retire but there is
no harm in trying it out. ;)
RICH
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Good luck with the new job Vince.
Tweakie.