Author Topic: small milling machine project  (Read 2450 times)

Offline tghs

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small milling machine project
« on: November 27, 2020, 03:08:11 PM »
not wanting to change the drive in my LMS 3990 mill for high speed +2500 for small tooling I decided to take another another look at my unimat SL100 milling column.. I modded it a while back with a lead screw for height control but the table and tramming was not workable,, the post/column is mounted on a base that has been cut away from the lathe bed,, my plan is to mount this base on flat base and add a milling xy table,, looking for suggestions on a base,, this small table is on its way,, the needed base should be around 6" x 12"
what the @#&% over

Offline cnr6400

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Re: small milling machine project
« Reply #1 on: November 27, 2020, 04:01:56 PM »
The bottom plate of a scrapped commercial die set can make a nice cheap precision ground cast steel machine base. A riser block of mild steel could bring your column bottom up to the XY table height to maximize tool Z height. Punch holder plates out of scrapped progressive dies make nice cheap precision ground riser blocks. Not sure if you have any diemaking shops for the stamping business near you, but if you can find one and ask about any scrap die sets or punch holder plates, you might be lucky. Also broken HSS punches from these dies make excellent cutting tools in the home shop. Dead hard outside but very tough inside, they are made for a tough life.

A pic from the Anchor Danly Die Set catalogue is attached to show what I mean re die sets. Just food for thought.

Die sets are costly when new, but when worn out or make obsolete punched parts, the top and bottom plates can be got very cheap at scrap value or less (sometimes a tray of coffees at the back door of the diemakers' shop). The plates may have lots of holes in them, you have to work around existing holes, but they are precision ground good quality steel. Generally the pins and bushings are what wears, and even after millions and millions of hits the ground surfaces of the plates are like new.
"I've cut that stock three times, and it's still too short!"

Offline tghs

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Re: small milling machine project
« Reply #2 on: November 27, 2020, 05:00:42 PM »
some surfing around found that a sherline inch milling column can be had at decent price,, now thinking that my unimat powerhead cloud be modified to fit and give much better control.. (this is a second powerhead I have so the lathe won't be touched) days away from the shop can be dangerous..
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Offline Steve Crow

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Re: small milling machine project
« Reply #3 on: November 29, 2020, 11:20:15 AM »
I bought a small table identical to that for a light milling machine project.

I found it a good heavy table which served its purpose. But.... you have to treat it as a kit of parts.

The one I got, on dismantling, was thick with swarf and cast iron infested grease and had lots of nasty sharp edges. It needed stripping to its component parts and given a thorough cleaning and deburring.

The next thing to do was throw away the gib strips which were badly scored.  The nasty gib screws went in the bin as well.

I made new gib strips from brass flat bar and replaced the screws with pointed grubs and added brass half nuts for locking.

I also drilled and tapped a fourth gib screw hole in each axis and added screws and levers as carriage locks.



If you look on the picture below you can just see the ends of the new brass gib strips.



I seem to recall adding thrust bearings somewhere down the line.

At the end of the day, I ended up with a nice smooth table once I had set everything up and adjusted it.

After that I mounted it on a cast pillar drill base - I can post pictures of that if you want.

I hope this doesn't put you off - maybe I just got a bad one. It was very cheap and I accept that you get what you pay for.

I haven't used it (or seen it!) for a couple of years since I got my Sherline mill.

Steve


Offline tghs

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Re: small milling machine project
« Reply #4 on: November 29, 2020, 01:42:04 PM »
I was expecting it would need a good rework to get to what I want out of it, kind of looking at it as one step above buying castings,, do like the addition of the locking screws, thinking that some swarf covers may be needed also.. this build up will just be an additional tool to the mix mainly used when working under 1/8" tool size. I also looking hard at a new bench lathe and maybe this little project will keep me occupied until the tariff situation changes.. I found some laboratory cast iron ring stand bases that may meet the needs as base for this rig..
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Offline tghs

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Re: small milling machine project
« Reply #5 on: November 29, 2020, 03:25:31 PM »
not be able to find it on any websites can someone give the base measurements of the sherline milling column.. tia todd..
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Offline crueby

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Re: small milling machine project
« Reply #6 on: November 29, 2020, 05:15:21 PM »
The base of the column is 2" wide by 2.975" deep. There are two .270" holes, 2" apart, centered on the base to fasten it to the baseplate assembly. Two more holes, 2.5" apart and offset .400" to the sides of centerline clockwise. These measurements were taken from the column riser block that I have. You can find SOME, not a lot, of dimensions here:
http://www.sherline.com/standard-dimensions-of-sherline-tools/
But, I thought you were using a Unimat column you had?

Offline tghs

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Re: small milling machine project
« Reply #7 on: November 29, 2020, 06:22:47 PM »
I'm looking at maybe adapting my unimat head to a sherline column,, looks like it could end up being a nice little mill..thinking the sherline column will be better than the modded unimat column....
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Offline tghs

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Re: small milling machine project
« Reply #8 on: November 30, 2020, 09:06:41 PM »
the table arrived today,, glad I have perfect piece of brass to make the gibs (won't call the ones that came with it gibs) ordered up the needed screws and nuts,, it is actually a little more robust than expected..
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Offline tghs

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Re: small milling machine project
« Reply #9 on: December 01, 2020, 10:59:34 PM »
looked hard at the unimat spindle holder and converting it wouldn't  be that simple of a deal , so going to stay with my modified unimat column,, thinking it should work out fine with a tweak or two..(plus it will keep a little more cash in pocket) set up the tilting table on the mill to cut the angles for the new gibs..
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Offline gary.a.ayres

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Re: small milling machine project
« Reply #10 on: December 01, 2020, 11:51:02 PM »
Interesting!

Notifications turned on...

 :popcorn:

Offline tghs

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Re: small milling machine project
« Reply #11 on: December 02, 2020, 05:52:45 PM »
zeroed the titling table(first time for using the table)-zeroed the small vise, set the angle, cut the stock (yeah used the new saw) very quickly milled out a set of correct brass gibs,, added photo of the lead screw added milling post..
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Offline Mcgyver

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Re: small milling machine project
« Reply #12 on: December 23, 2020, 01:43:14 PM »
You've probably got this all together by now, but I just noticed the topic.

I've done the sows ear to Swiss machine quality thing and put a bunch of content on my web site about it.  You can make one of these x/y arrangements perform like an Aciera with a bit of elbow grease

https://www.metallum.shop/projects-2/#minimillxy

Offline tghs

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Re: small milling machine project
« Reply #13 on: December 23, 2020, 02:54:05 PM »
thanks great stuff!!!  been tuning up the table,, new correct gib screws arrived,, still need to drill and tap for the table locks,, working on a base plate and a block to raise the milling column fixture..
what the @#&% over

 

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