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skipd1
12-26-2012, 07:47 PM
I would like to expand the work envelope of my clausing 8520 vertical mill as with a decent vise the span is bout 11 inches. I have not had any luck finding a factory column extension so I am wonder if it is possible to make one out of heavy tube or welding a stout block and trueing it up on the lathe. What to you guys think is the best way to do this, without spending a fortune and hopefully keep the regidity in my mill. I was thinking of 4-6" lift.

Skipd1

loply
12-26-2012, 08:19 PM
Could you possibly adapt something like a milling cube?

Alternatively I don't see why something couldn't be welded up from steel plate, probably with internals webs/ribs, then machined and scraped so the top and bottom are totally parallel... I don't know if the lathe would deliver the flatness and parallelism required, but I'd imagine it would get you close.

Jaakko Fagerlund
12-26-2012, 08:33 PM
I would just take a big enough heavy wall tube and clean it up on the lathe and true it. If one needs extra precision, then grind it flat, but I'm sure you don't notice any problems if you just face both ends in the lathe.

Best would be if one can face both ends in one setting, like having a mandrel or something where the tube is attached so that the ends are free for facing cut.

Edit to add: Even with turning the part around in the lathe chuck, you can use a DTI on the faced end to get it true and then face the other end. This way you get a block that is better than 0.01 mm flat and more than enough for the mill.

Bob Fisher
12-26-2012, 09:25 PM
You will certainly lose some rigidity by using a riser, but I'm sure you are aware of that. However, if you have tilt in both directions, you should be able to tram 'em out when the riser is in use. Bob.

Robo
12-26-2012, 10:15 PM
Some guys use 2 8" weldable steel flanges to make a riser for millrites. Not sure exactly the configuration on the clausing mill but perhaps it would work.

SGW
12-27-2012, 12:15 AM
You can get a 4" length of 6"' dia cast iron from Speedy Metals for $66.00. (I'm guessing 6" dia. is about what you would need.) I think that would be the most solid and elegant way to do it.

Do you really need a 6" riser? 11" of clearance above the vise seems pretty good to me -- I've got about 12 1/2" spindle to the table, or more like 9" above the vise. I've managed to make that work since 1985, though I have recurring thoughts that a riser would be useful.

oldtiffie
12-27-2012, 12:33 AM
Here is the Clausing mill referred to:

http://www.practicalmachinist.com/vb/attachments/f12/6446d1221765447-original-clausing-8520-knee-mill-left-view.jpg

http://www.google.com.au/search?q=clausing+8520+vertical+mill&hl=en&tbo=u&rlz=1W1IRFC_enAU360&biw=1920&bih=818&tbm=isch&source=univ&sa=X&ei=887bUNCkHs_MmAXouYGgAQ&ved=0CGkQsAQ

http://www.google.com.au/#hl=en&tbo=d&output=search&sclient=psy-ab&q=clausing+8520+vertical+mill+&rlz=1W1IRFC_enAU360&oq=clausing+8520+vertical+mill+&gs_l=hp.12..0i30j0i8i30l2.4032.4032.0.10758.1.1.0. 0.0.0.280.280.2-1.1.0.les%3B..0.0...1c.2.vz4xh9LspYw&pbx=1&fp=1&bpcl=40096503&biw=1920&bih=818&bav=on.2,or.r_gc.r_pw.r_qf.&cad=b

From what I can see a spacer ring should do it - can be shimmed if needs be. Design is up to the OP.

Jaakko Fagerlund
12-27-2012, 04:53 AM
About the material: You can just use ordinary structural steel like S355 or similar, doesn't matter much in that place if it is steel or cast iron. I would just use what I find.

outlawspeeder
12-27-2012, 05:37 PM
The place I go for steel has a couple of 1 inch wall pipes. Each one is about a foot and that is what he sells them for. Even has some in SS if you want to go over the top.

He does ship but I couldn't tell you if he has what you need.
http://shapirosupply.com/

getting it usable would require some work. weld on the inside bolt downs and tabs for the spider to ride under.

I thought about it for my BP but found one built that the own says he will loan to me when needed. Rules for loaner tools apply.

mike4
12-27-2012, 08:16 PM
1 Elegance and machining?
2 I find quite often that a part just clears the base of the spindle , before any tooling is fitted , a 6 inch riser will just make the grade occasionally , I am currently collecting 25mm plate offcuts to make an 8 inch unit which will be used for about three months of the year to machine weldments for another business.

25mm steel is easier to work with than cast iron and I personall consider it safer to use in this application , my machine and the parts add up to several thousand dollars , not to mention me .

I have seen cast iron extensions crack after about a week into a job if there are cuts which cause severe vibration and shock loads.

Normally the machine does move a little when a cutter insert leaves this world, ( as can happen in heavier work), but add an extra 6-8 inches to the height and I like to have something made of material that will flex rather than break if any thing unforseen does happen .

I find that it is easy to lift the vertical section up with either a crane or forklift and bolt the extra section in , check for square in all axes and fri tooling and start cutting .

Michael

skipd1
12-28-2012, 02:50 PM
Thanks everyone, there's a lot of great options for me to consider. After listening to everyone I think 4" is enough and a good compromise for rigidy. I will try to build something using my 9" lathe.
Thanks again, this is a great forum!!!!!!!!

Skipd1

skipd1
12-28-2012, 02:56 PM
There are 2 mounting bolts that need to go thru the extension to the base. So, and because it needs to turn or swing, the extension needs to be hollow. I think I could get away with 1" or 3/4" walls and have it work okay. Would that be strong enoungh if only 4" thick? Maybe use DOM Pipe?

Skipd1

Jaakko Fagerlund
12-28-2012, 03:20 PM
Plenty strong, remember that it is in compressive state when bolted down, so getting 4" long that thick pipe to actually buckle requires at least 11 unicorns in weight.

strokersix
12-28-2012, 03:45 PM
I had a local shop cutoff and turn both ends of a 12" diameter steel tube about 3/8" wall thickness 8" tall for my grizzly turret mill (the one that looks like a 7/8 scale BP, now discontinued). They got the faced ends parallel within about .001". Since my machine does not have a knuckle and can only tram side to side this was handy. I selectively rotated the riser to zero out the nod tram. I have since purchased a factory 4" iron riser but I keep the steel tube in case I need the extra height someday. Worked great.

Reed
12-28-2012, 05:02 PM
I added a riser to the Johansson mill (and the 7/8ths of a BP, Enco mill) which is the same as the Clausing 8520. What I did was make it from 1" plate. It measured 6" square and has about 4 3/4" height. After welding it up, I heated it in the crucible furnace I used for casting to normalize it. Then turned it in the lathe for the mating surfaces. It took a couple of attempts but I managed to eliminate needing shims. I have pics but hate the method this forum uses. If you have interest in them, PM me.

About that rigidity issue folks like to bring up. Didn't seem to make much of a difference. This is a small light mill and it never was much to do heavy cuts before the riser and did the same cuts after installing the riser.

The Enco mill was an easier story and adding it since it was mentioned. A fellow went through the hoops to figure out that the Grizzy 7/8ths BP clone was the same as the Jet. With his info I managed to search out that the Enco was the same "factory" model as the Jet/Grizzy. Grizzy sold a 4" riser for its mill. I bought it and it installed without modification.

- Reed


I would like to expand the work envelope of my clausing 8520 vertical mill as with a decent vise the span is bout 11 inches. I have not had any luck finding a factory column extension so I am wonder if it is possible to make one out of heavy tube or welding a stout block and trueing it up on the lathe. What to you guys think is the best way to do this, without spending a fortune and hopefully keep the regidity in my mill. I was thinking of 4-6" lift.

Skipd1