584,800 active members*
4,603 visitors online*
Register for free
Login
Page 1 of 2 12
Results 1 to 20 of 33
  1. #1
    Join Date
    Feb 2013
    Posts
    26

    Welded steel mill hybrid

    ]Well after reading a lot started my small mill project.
    Started off with 2" square tube and 1/4 on top for bolt down points. Had out the little welder was not doing the job. So got out the bigger one after making a power cord for it. Discovered I don't like 6011 rod. Should have got the 6013. Got the base welded gonna need clean up. Did a small mockup up of what I have in mind for the column.
    Click image for larger version. 

Name:	2013-03-10 18.21.40.jpg 
Views:	0 
Size:	73.2 KB 
ID:	179653Click image for larger version. 

Name:	2013-03-10 18.21.14.jpg 
Views:	0 
Size:	61.9 KB 
ID:	179649Click image for larger version. 

Name:	2013-03-10 18.50.27.jpg 
Views:	0 
Size:	112.5 KB 
ID:	179650Click image for larger version. 

Name:	2013-03-10 18.46.38.jpg 
Views:	0 
Size:	75.5 KB 
ID:	179651Click image for larger version. 

Name:	2013-03-10 18.42.19.jpg 
Views:	0 
Size:	110.2 KB 
ID:	179652

    Well it got dark but did a bit of wire wheeling to the base. I really need to practice my welding more.

    Click image for larger version. 

Name:	2013-03-10 19.22.39.jpg 
Views:	1 
Size:	112.5 KB 
ID:	179654

  2. #2
    Join Date
    Feb 2013
    Posts
    26
    I swapped one of my band saws for a hf mini lathe has broken gears. I think I can use the spindle on it and use the bed for part of the column. Remount the head to the lathe saddle with a spacer. Redo the lead screw and halt nuts. Anyone have any thoughts on that? I have plans for part of the bed as a tail stock extension. Also looking for some guidance about building the column. I was thinking 2 flat plate behind the column at 45 degrees or maybe to 2 1 " pipes diagonally. Just have to make them bolt on so the column can be squared up.

  3. #3
    Join Date
    Mar 2012
    Posts
    19
    The only problem I see with the mini lathe spindle is the same problem that comes with all X1, X2, X3 mills as well, and that is not fast enough spindle speed. You said the gears were stripped, so that would be an opurtunity to speed things up some. The problem with the speeds on these is that they really aren't heavy enough to use a much bigger cutter than 1/4" effectively. Given that you're likely going to be using 1/4" and smaller end mills, you can use high speeds, especialy in aluminum. Of course, having some power down at the lower end of the range is good for using slitting saws (4" HSS slitting saw in soft steel should be ~200 RPM, and would likely be too much for that small a mill). If you're going to mod it, as I expect you will be, speed range is something to keep in mind.

  4. #4
    Join Date
    Feb 2013
    Posts
    26
    Have a 1.5 hp treadmill motor and control for it for power. Changed my mind about the column. Going 4" square column with 3/8 thick box ways. Picked a 4" square tube at metal supply. They have a good supply of drops so prices are good for metal. I'm thinking for the column filling partially with concrete. With a round pipe inside the square column pipe.

  5. #5
    Join Date
    Feb 2013
    Posts
    26
    Got the column welded out today. Getting better With 6011. Braced 4 inch column. After lapping and drilling and tapping will be partially filled with concrete. Will have a smaller pipe inside column.
    Attached Thumbnails Attached Thumbnails 2013-03-17 19.15.38.jpg   2013-03-17 19.03.55.jpg  

  6. #6
    Join Date
    Feb 2013
    Posts
    26
    Got more work done on the mill. Not much hybrid about it any more. Was going to have an aluminum saddle no more. All welded steel. More filing and lapping needed on the saddle,but need to get more complete. Need to fab the jibs and pick up 3/8 key stock for the other jib.
    Click image for larger version. 

Name:	2013-04-21 16.06.26.jpg 
Views:	0 
Size:	98.0 KB 
ID:	182169 Click image for larger version. 

Name:	2013-04-21 16.06.53.jpg 
Views:	1 
Size:	100.7 KB 
ID:	182170

    Another thing I would like a rotatable headstock but need to think about how to do?

  7. #7
    Join Date
    Mar 2012
    Posts
    19
    Generally steel on steel sliding surfaces are usually avoided, due to galling and "stiction" issues, even when well lubricated. I had some thoughts about using silicone bronze mig wire or bronze oxyacetylene to build up a thin surface on steel parts, then hand scrape it flat. Using this on one of the surfaces would avoid the steel on steel problem. There's also the option to fab one member from cast iron bar stock, but that stuff can get expensive. Another option is using cast iron or bronze wear strips attached with screws. One thing you may be able to do is get the machine going as is, and then machine the parts to take care of the steel on steel problem with it. The problems will affect long term performance, but shouldn't be much problem in the short term. How are you squaring the machine? Oh, and its gib, not jib.

  8. #8
    Join Date
    Feb 2013
    Posts
    26
    To square the column to the base am going to go with epoxy replicated joint. Very similar to what Zach did on his mill:http://www.cnczone.com/forums/vertic...tml#post985144 The box way on the column Is a very flat piece of cold finish steel. Checked with a granite plate and indicator. 0.0002" from end to end. Seems good enough to me. Set on bedding epoxy then drilled and tapped. The machine base I stripped back down and bedded with the the same epoxy using the surface plate as the flat surface.

    Hmm braze in wear surfaces I could do that. Braze rod would have some silver in it though. The side "GIB" could be brass. Or maybe use the partially completed saddle to get the mill working than use that to fab a cast iron saddle.

  9. #9
    Join Date
    Mar 2012
    Posts
    19
    Sounds like you have alignement under control. Looking forward to seeing your progress. Another thing I thought of after the last post was Turcite. That's a brand name of a polymer way material (there are others, Moglice is one) that is used on some comercial machines. It's used on the Tormach mills, for example. I did a search for it a year or two ago, but had difficulty finding it available in small quantities. If you have a machine tool rebuilder local to you, they may be willing to sell a small amount. The ways are roughed up a bit for bite then the polymer material is epoxied to the way, then it is hand scraped. You have to be a bit careful scraping it, as it is fairly soft, but it can be done. Technique is the same as cast iron, just much less pressure is applied. As far as deflection is concerned, the stress on the ways is normaly kept down to under 35 psi even on normal cast iron slideways, so it isn't normaly a problem. You might need to do some calculations as to what you're way pressures will be under high cutting loads just to make sure it would work ok.

  10. #10
    Join Date
    Feb 2013
    Posts
    26
    Saddle is mostly completed. Still need to pickup keystock and shim material. Will probably use aluminum can for shim stock. As far the saddle being all steel. Will just have to see how the mill operates. See if there is any stiction or galling.
    Click image for larger version. 

Name:	2013-04-28 17.21.48.jpg 
Views:	1 
Size:	90.8 KB 
ID:	182555 Click image for larger version. 

Name:	2013-04-28 17.22.13.jpg 
Views:	0 
Size:	70.2 KB 
ID:	182556

  11. #11
    Join Date
    Feb 2013
    Posts
    26
    Got more done on the mill. Drilled and tapped holes for the column and table. Bolted and aligned the column then filled with epoxy/aluminum oxide slurry for a "replicated joint". Filled column and base with none shrink concrete column with 4 pieces of re-bar and 2" scrap gas pipe. Ends sticking out will be cut off level after concrete sets a few days.


    Attachment 186140

  12. #12
    Join Date
    Sep 2006
    Posts
    6463
    Hi, you can use strips of .020" brass shim between the steel faces, turned up at the ends and secured with screws to the saddle to prevent steel on steel contact.

    Make the strips about 2"wide to leave the centre of the slide clear of the mating part......keep well lubed with oil.

    I used this method for a lathe saddle and crosslide.
    Ian.

  13. #13
    Join Date
    Feb 2013
    Posts
    26
    Handy would you use the brass shim stock on all surfaces front side and back?

  14. #14
    Join Date
    Sep 2006
    Posts
    6463
    Hi, yes, wherever you have any metal sliding on any metal and they are soft, as in mild steel, they will both erode each other.

    Cast iron on cast iron will also erode if it runs dry, but it has a tendency to rub a hard skin and so resists galling and in addition it has graphite in the material....it will still gall if the slides run dry.

    Using brass just makes a dissimilar metal surface with the steel being the harder and the brass sliding over it.......lubrication is a very necessary factor for all sliding surfaces.

    In your build I would MOST DEFINATELY consider fitting linear ways, Hiwin or the round fully supported rails......cheap at the price and are instant sliding ways.

    You will spend more time just getting the ways, you are contemplating on using, to fit properly, as opposed to just facing the pads you now have and bolting on the linear ones.

    Sliding ways are only good if you have a solid heavily braced infrastructure that will maintain the fit whereas with that amount of welding present, the stresses locked into the framework will make fitting very difficult.

    If linear ways are out, then I'd use brass shim between the faces all round as needed, making the sliding members brass on steel wherever it occurs, IE the saddle has the brass shim attached to it and slides on the steel of the base.

    Same goes for the column/head slideways........the head has the brass shim between the faces......making sure you bend the ends of the shim up at the end of the slideway and secure to the respective parts with a couple of screws.

    You'll have fun and games fitting the column slides if you don't have something to check the alignment with, like a surface plate or even a mill table, and without any means of making the column slides true, sliding will not occur.

    You'll have to make all the sliding ways true whichever method you use.....this will make or break any build.

    In the lathe I mentioned previously, the bed was machined flat and true before any assembly with the brass shim material.
    Ian.

  15. #15
    Join Date
    Feb 2013
    Posts
    26
    The column way is very flat cold rolled measured at 0.0002 out across its 15 inches on a surface plate. The steel guy let me pick my piece. The way is bolted to 2) 1/2 x 1 hot rolled. It was set with epoxy/aluminum oxide mix then bolted down. So at least that is flat. The width does vary from 3.998 to 4.003 But I can get that trued up with elbow grease and a file. I know its very hard to build a mill without a mill. The current saddle may become sacrificial. Use it long enough to mill a cast iron saddle. We'll see how it goes. I like the brass shim idea. But not happy with current saddle. Don't have much $ invested in this project. Alot of time but hell its a hobby

  16. #16
    Join Date
    Sep 2006
    Posts
    6463
    Yeah, elbow grease will save the day when other methods are lacking.

    A guy in the UK in the 60's posted an article in the Model Engineer about a small table top Horizontal borer he made, using just raw castings and no machinery.

    Using the traditional old time methods of chipping the casting with a hammer and chisel to get beneath the skin then filing and scraping etc.

    This was purely to prove that anyone can make a machine without a mill or lathe using the methods and hand skills already proved, even though time consuming.

    In a build like you are doing, I think the linear ways will give you more joy, but that's just my preference.

    I was quite tickled by the gluing of the column pads, and at least you have access to a surface plate to check your build, so all is not lost due to inaccuracy of alignment.
    Ian.

  17. #17
    Join Date
    Sep 2006
    Posts
    6463
    ooops....double up on post.

  18. #18
    Join Date
    Sep 2006
    Posts
    6463
    BTW, just had a thought.....dissimilar metals work together, with lubricant, so I suppose you could have one piece of the slide way coated in zinc by having it electro plated, (the moving part), and you would have a material that would separate the two steel faces from attacking one another....probably only require a light rub on some wet and dry to take out any high spots etc.

    If the slide way zinc coating was thick enough it would last for quite a long time, provided it was kept well oiled.
    Ian.

  19. #19
    Join Date
    Feb 2013
    Posts
    26
    Ok I'll just ask. If you keep it oiled why is steel on steel surfaces so bad?

  20. #20
    Join Date
    Sep 2006
    Posts
    6463
    Hi, you will always get metal to metal contact at some point and it only takes one contact to rub up a burr.....goodbye slide.

    If you want to have peace of mind, I'd simply go with the brass shim method as it works and is a good combination, provided you keep the lubrication supplied.

    Brass will also "weld" itself to steel if you neglect the oiling completely, but you'd have to completely forget to oil it.

    The point of dissimilar metals is one is a sacrificial part, like in a car's big end bearing....white metal shells, but here we have pressurised oil all the time.

    In the case of your mill build, the slides are steel on steel, and the proposed liners are brass shim......brass shim can be replaced without the steel being affected, but it still needs regular lubrication.

    Under CNC control, the slides are in constant motion, and so there is a tendency for the back and forth movement to migrate the oil out of the slide.

    In a CNC build, you would be strongly advised to fit linear ways on all axes as it is the heart of the machine movement control.

    Any sliding surface is prone to failure due to lubrication failure.
    Ian.

Page 1 of 2 12

Similar Threads

  1. CRP2448 Rebuild: Welded Steel Base and Rackmount Electronics
    By Gerald V.B. in forum CNC Wood Router Project Log
    Replies: 7
    Last Post: 02-17-2013, 08:12 AM
  2. 2nd machine, welded steel
    By lazorus in forum DIY CNC Router Table Machines
    Replies: 18
    Last Post: 09-11-2012, 09:31 PM
  3. My First All Welded Steel Router Design
    By widgitmaster in forum CNC Wood Router Project Log
    Replies: 9
    Last Post: 10-18-2008, 03:07 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •