|andrew lyner||06/01/2019 17:47:27|
|63 forum posts|
I bought a vertical milling slide for my super mini lathe and it has turned out to be much better than I feared. That is a long as I am prepared to take the smallest nibbles and the gentlest feed rates. No real problem as I am not earning money with it. Size of workpiece is a serious limitation, however.
I'm sure that a proper milling machine would be great but the only available used ones are really old and too massive and a new mini milling machine will cost as much as my new lathe setup did. (£600 plus)
Now, bench press drills are cheap as chips on the second hand market and you need drive only a few miles to pick one up, apparently, at the drop of a hat. If I were to buy a reasonable milling table, what would be wrong with bolting it to the base of my drill and just buying a new drill when the bearings start to go wobbly?
Is that a totally daft idea as a way of getting long dovetails and slots in aluminium?
|Jeff Dayman||06/01/2019 18:47:20|
|1402 forum posts|
Ridigity is everything for milling. Drill presses do not have enough rigidity for milling. I and many others have tried to make it work but it simply doesn't. if you search this site you will find multiple posts about it. If you want to do heavier milling than what you are doing in your lathe, get a mill, find a chum with one, or make your own via the Dave Gingery plans or other plans. I have a friend that built a very serviceable mill from mild steel electric welded together. He used the Gingery books as a guide but made many improvements. It is not as rigid as a similar sized cast iron mill, and does deflect under heavy cuts, but in normal use it works fine. The column is 6" x 8" rectangular mild steel tube 1/2" thick, about 6 feet high.
|Mike Poole||06/01/2019 19:12:14|
1753 forum posts
Drilling machines are much lighter than mills and effective holding of a cutter is difficult. The first problem is that most drills have a morse taper and no drawbar to retain it or a milling chuck. A milling cutter generates substantial side loads and these will pull the taper out or the cutter if a Jacobs type chuck is used. Just spinning the cutter is not enough as the machine must resist side loads that release unsecured tapers and axial forces that will move the cutter and possibly break it. Many have tried this and it usually get abandoned, if you are lucky before you try it and probably after it all ends in a wrecked job and broken bits.
3462 forum posts
Is that a totally daft idea
I'm afraid you have some serious competition on daft milling ideas in here
Drilling machines tend to lack longitudinal stiffness support, but if you're gentle... well maybe
For myself, serious attempt one was not too bad but a decent envelope is a major problem, quite frustrating really
The other issue is the centreline on the slide moves as you move the cross slide across the tool, so the loading changes across the face of the milling slide, introducing more potential errors. A decent milling side was up to 100 quid plus last time I looked so I've gone for one of these for two hundred quid delivered
I only just got it a couple of days ago and it will take a while to sort out then test out
If I fails I've still got a fabby drilling and co-ordinates table
Getting a decent alternative to a proper mill has been an eternal problem for ME people
A proper unit is usually 500 to 3000 quid and weighs up to 3 tons, plus you have transport and space-for-it issues to contend with
So don't worry about looking daft and give it a go while they're all looking in my direction
|Martin Hamilton 1||06/01/2019 20:00:48|
|69 forum posts|
You will soon knock the bearings out milling on a pillar drill, a milling machine is intended to take both side & end loads.
|andrew lyner||06/01/2019 22:39:00|
|63 forum posts|
@Ady1: Attempt 1 is really impressive. As a total rookie welder, I can appreciate the welding in your list of pictures of the project. Your final solution looks like a good one. I can see several tables at around the £200 mark. Problem with using the lathe for turning plus milling is that it takes an age to swap over.
I shall just have to keep an eye on Gumtree. Shame about local paper classifieds and Friday Ad, eBay is fine but there are so few real bargains these days.
Having said that, I got a good deal on a Sealey Wig welder a few weeks ago. "Attempt 1", here I come!!!
|larry phelan 1||07/01/2019 13:32:37|
|375 forum posts|
Drilling machines are for drilling holes
Milling machines are for cutting slots [along with other things ]
Simple as that !
The short answer would have to be-----not really a good idea.
|52 forum posts|
I adapted an old Pollard bench drill for milling. This involved a lot of work including: changing the bearings to tapered rollers, designing and building a fine down feed with clutch, quill lock, making a collet chuck, raising the column to regain the headroom lost to the x-y table, and, of course, the expense of buying the x-y table. Since then, I have built a new belt drive system to give more speed choices and considered making a new spindle in order to reduce the bottom bearing to cutter distance.
Although the Pollard is hefty for its size, it is still not rigid enough for meaningful metal removal as a milling machine. Plastic is easy but anything else is frustratingly slow. Take the advice of someone who regrets wasting a lot of time tail-chasing. Forget it and buy Chinese. You could be making things that you want to make instead of flogging a dead horse.
Edited By AlanW on 07/01/2019 15:23:54
|Howard Lewis||07/01/2019 15:40:48|
|1757 forum posts|
Milling is series of interrupted cuts, so the machine needs to be rigid. A drill press, is not.
The helix on milling cutters, such as End Mills, means that they will try to screw themselves out of the holder, (and sometimes succeed!)
personally, I doubt if a cross table will really be rigid enough, either, so you could well have a lack of rigidity in the machine head and the table. Has to be a recipe for disaster.
My Mill/Drill is barely rigid enough unless I stick to fairly light cuts.
It may be costly, but use the right tool for the job.
|126 forum posts|
While I do not advocate using any of the following - singly or collectively - and I have not tried them myself here are a few reference/assorted notes. Unless a source is stated I have no additional information regarding sources.
Look at Popular Mechanics July 1954 & Jan 1969: also, Pop Science Jan 1952 (Google online for the link). These often describe building an adapter to provide additional lateral cutter support.
MEW Jan/Feb1996, Issue #33
End mills are hard; they are harder than the jaws on a drill chuck, so the jaws will not grip them the way they grip the soft drill shanks. This means the axial retention force for an end mill is poor, it will suck out due to the helix angle on the end mill. Drill chucks only support the tool at three points around its periphery. This allows the tool to move sideways to some degree - a lack of rigidity.
If doing this purchase the largest Jacobs ball bearing superchuck that would fit the machine. When installing it I would aggressively clean the taper socket and the arbor with clean solvent, and heat the socket and cool the taper before installing.
|Ron Laden||07/01/2019 17:28:19|
|929 forum posts|
Not too long ago I considered getting a table and using my bench drill for milling but as you are seeing now a number of guys here told me not to go there as it doesnt work.
I also know too well the frustration of a tight budget, I was saving for a new mill and wasnt quite there but I was fortunate in that a forum member offered me his SX2P mill as he was upgrading to a larger machine.
You mention £200 for a table, I dont know your budget that is your business but ARC with their current price reductions offer the SX1L mill for £387 including VAT, I think that is around £100 less than the normal price. I dont know a lot about the machine but have heard reasonable reports of it for a small machine. It has a 400 x 145 table and almost the same spindle to table distance as I have on the SX2P. The motor is a brushed 150 watt (output) and it has a high and low gear box and I read that the torque in the low range is quite decent. I dont know what type of work you would be doing but if as you mention long slots and dovetails one would think it would cope with those, it may mean shallow cuts but that would be true of any small machine.
I dont have any connection with ARC but it is a mill and could be worth considering if your budget could run to it.
|Dave Halford||07/01/2019 18:03:04|
|320 forum posts|
Most dovetail cutters are more than 1/2" shaft so you need to work back from the dovetail size that you need to produce, which sizes the cutter, which in turn sizes the chuck / collet to hold it. You could be looking at a MT2 taper to hold the cutter. Collets/chuck not retained by a drawbar have been known to come loose with interesting results
|andrew lyner||08/01/2019 11:52:49|
|63 forum posts|
Things will have to get worse and I will need some more money before I actually commit to any expense in this direction. But the thread has been useful (as ever on this site). Thanks for all the opinions chaps.
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