Rotary table, and looking at my SX2 again...

Duke

Duke

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After a couple of months of being too busy to spend time in my workshop, I got a new rotary table for my sx2 milling machine.

The one that I got is a six inch phase 2.

Initially I was a bit concerned that the table will be too big for the mini mill, but after fitting it, everything seems to work out ok.

rotarytable.JPG

This specific rotary table is the only one that was locally available.

Overall I am extremely happy with it: the thing is built like a tank and the handwheel operation is exceptionally smooth and accurate. The locking levers lock the table securely in place with absolutely no movement.

When filling it with oil, I guess I overdid it a bit since it had a tendency to leak out the excess oil but it has now stopped and the oil level is centered in the sight glass.


In this photo it looks like the rotary table hangs off the front a lot - probably the camera fov. In fact it is pretty well balanced.

The mill seems to handle the weight of the rotary table ok - the x and y hand wheels are obviously a little bit stiffer but nothing too extreme. As a precaution I just make sure that all the dovetails are well lubricated.

I can mount my small grinding vise on top of the rotary table - this becomes a very high setup and eats up most of the horizontal travel on the mill, but overall the advantages outweigh the disadvantages. Sweeping the top of the grinding vise (on top of the rotary table) I get an error of 0.002 inch over a distance of about 7 inches which is good enough for me.

Being able to accurately rotate the vise through 360 degrees makes it easier to handle and machine longer parts: if something is too long, I rotate 90 degrees and mill using another axis.

Aligning the vise is also a very quick operation:

1. Indicate the center of the fixed face and set the test indicator to 0.
2. Sweep to the side and rotate the table until you also get 0.

Done.

The only problem I have is with drilling since some of the larger drills are too long. I will have to shop around for a couple of shorter drills at some stage.

At the moment I am building a clamping kit for use on the rotary table when the vise is removed. I have already made an mt2 tapered plug for the hole in the table to assist with centering everything.

Made 4 brass t nuts last night and I am now experimenting with clamping setups....
 
Looks good, and if you ever buy a bigger mill you won't need to buy another rotary table :big grin:
Mark
 
Regarding drilling - it's often possible to use an appropriately sized R8 (or ER) collet to hold the drill bit, so you don't lose Z space to the length of the drill chuck (assuming you have an R8 spindle and use a drill chuck). It does look like you're using somekind of collet setup. ER32?
 
I have looked at the bigger mills like the sx3, but they get damned expensive over here. Currently my plan for a bigger mill is :

  1. Remove the column, head and rotary thing on the base of the column.
  2. Get rid of the base of the mill with the xy table.
  3. Build a new base and mount a sturdier xy table. There are xy tables available that are a lot heavier than the ones on the mini mill.
  4. Mount the mini mill column to the new base.
  5. Construct a triangulated scaffold support structure to the height of the hole in the column where the torsion spring bar used to be.
My idea is to build something that connects high up on the column that uses heavy duty bolts to adjust the tilt and forward backward lean of the column. Just a few mm.

This will make aligning the column a lot easier, and if the column is braced high up it will help a lot with overall rigidity.
 
Hi Duke. Congrats on the table. Looks huge on the mill. As long as it works for you. I would like to see your progress on your modifications of the mill. Do you think you will post as you go? Can you do your fellow South Africans a favour? Most of the members use the imperial system and a few of us use the metric system. So when you post,can you perhaps do a conversion from imperial to metric and perhaps put it on bracket? When I post, I do this the other way around for our American and other members who use the imperial system. I can work with the imperial system,but always have to do the conversion first. I only ask because you are from SA. It's only a request and you don't need to feel obligated. Good luck with your project.

Michael
 
Hi Michael,

Good idea - I will add the dimensions in both metric and imperial..

I will post the upgrades on the mill as I go along - the first step will be do do a 3D model on my PC of the proposed changes to get an idea of what has to be done.

Locally available mill options:

I can get an Optimum MH22V for about R 32 000. Very nice. Weighs about 116kg (255 lb).
Adendorff has a 40mm geared head mill for roughly the same price but it weighs 325kg (716lb). This thing is heavier than a 1200 GS Adventure...

However both of these are more expensive than what I am prepared to pay for something purely for hobby use, which is why I am looking at the upgrades on the mini mill.

The foundation of my planned upgrade will be this table:

EATABL-002.jpg

Its specs are:

425x240mm table (16.7 x 9.4 inches).

My mill weighs 50Kg (110 lb).
This table weighs in at 40Kg (88 lb) so I figure it should be an improvement if it is accurate enough.

I like the fact that the dovetails have a square footprint which gives more rigidity than what I have on the mini mill.

On the mini mill the x axis dovetails are a lot longer than the y dovetails. I have no issues with the x axis, but the shorter y axis gibs need to be tighter to prevent wiggle.

My concerns with this table are:

Accuracy: What are the increments on the dials. They should be smaller (more accurate) than on the mini mill since the dials look larger. The thread pitch of the leadscrews will obviously be a factor as well.

Operation smoothness : After a number of hours of tweaking, my mini mill's x and y axis handwheels are exceptionally smooth. This should be fix or tweakable.

Backlash ?

If this checks out, the rest will not be a major hassle. I can have the steel cut to size and I will weld the construction myself.

My welds look like chicken crap, but they hold ; )
 
Besides the price,I am not that comfortable with Above mentioned company for every day use. I see whay too much of thosr on Gumtree after not much use. So it tells me a story. Good luck and I see forward to your progress.
 
I've bought and tweaked several similar X-Y tables ... probably of a lower initial quality than the one you're looking at. If nothing else, the "dials" were really poor and it had a lot of backlash. Hope this one works well for you. My main concern would be with the X and Y motions. They look a bit limited - maybe 200-250mm X motion, and half that in Y?
 
Suzuki4evr said:
Besides the price,I am not that comfortable with Above mentioned company for every day use. I see whay too much of thosr on Gumtree after not much use. So it tells me a story. Good luck and I see forward to your progress.
Click to expand...

I am very happy with the small Milling Machine and Lathe I got from the mentioned Company. (As they are now.)

BUT..... dont expect to buy a mill / lathe from them and start using it right away. Consider the machine to be a kit: the machine has to be disassembled and a fair number of hours have to be spent tweaking stuff and replacing / making small components.

Fortunately this is part of my hobby, but not everyone has this inclination / or the time.

A second hand mini mill that has been tweaked is worth more than a new mill than you just bought from them.
 
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