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mike4
03-05-2011, 10:36 AM
Has anyone comtenplated making a steel spacer for their mill to gain extra height above the table , most of the commercially available ones are cast iron .

Have had some distortion problems with a few "new " cast items lately .

Many suppliers dont seem to care about quality as much as quantiy.

Just a thought as I will possible make it a permanent fixture as there seems to be a lot of jobs which require 50mm more clearance than the mill has .

I dont want to purchase a new one as this one has only done about 2.5 years work so far.

Michael

uncle pete
03-05-2011, 10:51 AM
If I remember correctly I think there was a artical about building one in the HSM magazine a few years ago. Steel pipe was used with welded flanges for bolting it to the coloum and the rams female dovetail block. I've never built one, But I think welding plates to seal up the internal space and fill that up with sand to dampen vibrations might be a good idea. It would be pretty heavy tho.

Pete

barts
03-05-2011, 10:55 AM
Cast iron is the ideal material here - it damps the vibrations, and is in compression where it is very strong. A steel one will work, but cast iron is better.

- Bart

Iraiam
03-05-2011, 11:37 AM
I think cast iron would be much better for this application, steel will flex considerably more than cast iron, although possibly just a big block of steel as a spacer would show little if any flex.

I have this problem on my mini mill. the best fix I have so far is to use a regular collet to hold tooling instead of the collet chuck it came with, which saves nearly 3 inches of vertical height.

I also have a plan to get another 1.25 inches out of it, it involves moving the stop at the top of the dovetail column and bolting on some made extensions. This will allow the use of the entire vertical cast iron dovetail, without ever traveling the head off of it. Right now when I crank the mill head all the way up until it hits the stop, there is approximately 1.25 inches of column left unused above it.

Lew Hartswick
03-05-2011, 11:41 AM
On the board "Shop Floor Talk" a fellow has just made one. He used
a section of pipe and welded a flange on both ends for the matting
surface. Worked very well. Of course it takes a good size lathe to
finish it properly.
...lew...

SGW
03-06-2011, 04:51 PM
I've contemplated it a lot. That's as far as I have gotten on the project. www.mcmaster.com sells 2" thick cast iron disks in large diameters for fairly reasonable cost. A 2" thick by 8" diameter disk is about $51. A 2" x 6" is about $42.

philbur
03-06-2011, 05:10 PM
All carbon steels are actually more than twice as stiff as cast iron for the same section.

Phil:)


..... steel will flex considerably more than cast iron

PeteF
03-06-2011, 05:11 PM
Yes I will do this for my little machine as I'm really struggling for headroom. Here's a link to the same mill with the riser block constructed, sorry no construction details but it wouldn't be too complicated, nothing fancy needed, just make sure it's all square.

http://www.lathes.co.uk/hercus/page4.html

Pete

bob ward
03-06-2011, 06:43 PM
Miker, there may be some ideas for you here.
http://ryanbrownracing.com/Bill_Jones_Page_10.html

platypus2020
03-06-2011, 08:05 PM
On the board "Shop Floor Talk" a fellow has just made one. He used
a section of pipe and welded a flange on both ends for the matting
surface. Worked very well. Of course it takes a good size lathe to
finish it properly.
...lew...



Lew,

The guy was me, and yes it has worked fine. Below is the thread link.


jack


http://www.shopfloortalk.com/forums/showthread.php?t=28383

strokersix
03-06-2011, 08:44 PM
I have an 8" tall, 12" diameter, 3/8" wall steel tube riser. No flanges, just longer studs. I used alloy all-thread. Swiveling the turret is inconvenient without the proper pilots but I very rarely swivel my turret so a non issue. The local shop I purchased it from turned the ends parallel for me within .001 for minimal extra. I selectively positioned the .001 for nod tram since my head only tilts side-to-side. Works great for me.

Mark Hockett
03-06-2011, 08:49 PM
Michael,
What kind of mill do you have?

lane
03-06-2011, 08:58 PM
For home shop use . Steel is fine I would dare that any one of you could tell the difference running one with a steel riser are a cast iron one . People get real.

mike4
03-06-2011, 09:29 PM
Michael,
What kind of mill do you have?
Its a HM52 which is similar to Grizzly 's offerings ,I purchased this one to save changing setups for some work that comes along .
Jobs which require both horizontal and vertical milling .

Now I have a batch of higher than normal parts to cleanup and modify for an application ,probably wont need the clearance again .

Making the riser and machining it is not a problem ,I just wanted to hear from others who may have already done this.

Forrest Addy
03-06-2011, 09:43 PM
Get a factory made riser for your turret mill. It is the simplest solution but also one that's expensive.

You don't say if yours is a turret mill Is it made like a Bridgeport stye mill where a milling head bolts on the end of a horizontal ram that mounts in a dovetail across a turret that swivels atop the column?

Anyway, a "riser" is what you're looking for. Here's a link to a few: http://business.shop.ebay.com/?_from=R40&_npmv=3&_trksid=p3910.m570.l1313&_nkw=bridgeport+riser&_sacat=12576

You can cook up a home made riser but the top and bottom faces have to be machined parallel and there are rabbet fits so the turret turns on an axis. If you don't have access to a machine large enough to face an internally flanged ring that's what? - 18" OD? You also have to drill for the bolts so the upper and lower hole patterns line up with the turret holes. The hole are necessary to carry the bolts along as the turret swivels, If the bolts hang free thay can swing a litttle and hang up in the T slot.

No reason you can't make your own (save a couple hundred bucks but don't forget to figure the cost of materials) but you do have to provide the necessary features to make it work.

JCHannum
03-06-2011, 09:59 PM
I believe Mike's mill is the Australian version of this Grizzly machine, in which a Bridgeport riser will be of little use. I see no reason that a steel weldment would not work. The mill appears to have the capacity needed for fabrication.

http://www.grizzly.com/products/Horizontal-Vertical-Mill/G3617

38_Cal
03-07-2011, 02:42 AM
Jim, a riser will work with that mill for vertical milling only. It will have to come off to use the horizontal feature, unless a new shaft support is fabricated to match the thickness of the riser.

David

form_change
03-07-2011, 02:56 AM
I fabricated a steel riser from sections of flat and pipe. This is it
http://i1140.photobucket.com/albums/n574/form_change/riserSmall.jpg

and the complete mill

http://i1140.photobucket.com/albums/n574/form_change/millSmall.jpg
This was some years back when the paint was still shiny. It's not that clean anymore...

Michael

mike4
03-07-2011, 07:08 AM
I believe Mike's mill is the Australian version of this Grizzly machine, in which a Bridgeport riser will be of little use. I see no reason that a steel weldment would not work. The mill appears to have the capacity needed for fabrication.

http://www.grizzly.com/products/Horizontal-Vertical-Mill/G3617

Thats correct ,its an exact match mechanically except mine has a ISO30 spindle .

I have looked at welding some 3/4 plate to form the block as I would prefer that the shape was similar to the mills existing column.

Just need to make some time available ,I have about a month to get it fabbed and fitted.

And thanks for all of the constuctive comments ,I hope to remember to get some photos of before during and after .

Michael

form_change
03-07-2011, 03:41 PM
Looking at the website photos
(https://www.machineryhouse.com.au/Products?stockCode=M161#)
there looks to be no reason a fabricated steel riser can't be put in. As a first option I'd probably go for the space between the column and the squarish bit with the angle scale. Trying to make up a round spacer is adding complication that may not be needed.

Michael

Davo J
03-07-2011, 06:23 PM
Hi Mike,
Not sure if you saw it, but we discussed risers for the HM52 mill over on the wood work forum a while ago.
http://www.woodworkforums.com//riser-block-mill-cast-iron-hollow-bar-where-get-bar-121294/


Dave

PeteF
03-07-2011, 06:24 PM
Michael your Tom Senior shares many similarities with the Hercus Type 0 mill I have. One difference is that the vertical dovetail doesn't extend right to the bottom of the machine. In other words it looks very much like yours already. I don't fancy having to fabricate a whole new slide extension and get it matched into the existing one, so I'm wondering how far off the bottom I should be able to run the knee before it starts to become unstable? I'm thinking just short of 1/2 way, so just prior to the gib locking screw, but that doesn't make for a large extension. How long is your extension and did you find this extension length was worthwhile?

Pete

mike4
03-07-2011, 10:11 PM
Jim, a riser will work with that mill for vertical milling only. It will have to come off to use the horizontal feature, unless a new shaft support is fabricated to match the thickness of the riser.

David
That is easier to fabricate than the original one which I asked about, just machine some 50mm plate to extend it down.

The original would require fabrication of a square steel riser about 200mm high overall , I was originally going to use 19mm plate but now have some 25mm left from a job ,this will make it more rigid and easier to work with.
Michael