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Modeler12

How to make best use of your milling machine. Tips and techniques

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Hi Geoff

 

With pine (provided you are not cutting through any knots) I would say cut the depth of the diameter and you will be OK i.e. 3mm deep for 3mm diameter etc.I would not go any deeper than 1mm for a 1mm cutter,you are more likely to snap the cutter rather than burn it out in this instance.I would halve this rule for harder woods ;)

 

Kind Regards

 

Nigel

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Another way to go is to see what happens with the feed:

 

   if you need to go too slow it means you want to chew too much

   if you can feed very fast  may be you could go a bit deeper

 

Often in these situations, as well as in turning, the middle is often the best way to go

 

you need to feed easily without any wobble in the machine

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One of the things I learned was if not sure take a light cut then go a little deeper with each cut .  This was how I learned to mill the stuff at work.  Hogging is a fast way to remove excess material but you have to be aware of what you are removing and the mill or cutting tool you are working with.  

David B

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I was asked a question on what I was working on. The main material is usually aluminum, stainless steel being laminated

to either shockpad and or cross-grained masticated. While they can be machined they tend to either burn out HSS bits and make

a lot of smoke. Carbide bits are used when available but you still have to be careful of your speed and feed. Since most of

the stuff we work with is non ferrous you have to learn the hard way and add notes in the mfg instructions for the next guy.

The first time I worked with a piece of polyurethane and clogged up the end mill and almost ripped the part out of the vice.

David B

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Ahoy Mates

 

To start with I am a now retired tool and diemaker who has been using mills of all types for the last 50+ years. What advice I would give all about milling is that,since you are not having to do it for a job with time being a large factor- Take your time milling. Small cuts do two things: 1- it saves wear on your cutters which are costly to replace and 2 nd  it reduces any deflection of either the cutting tool and reduces the over cutting of the mill cutter in your work piece.

 

The small milling machines are not built to handle deep cuts by the milling cutters. In size a standard Bridgeport milling machine handles cutters up to 1" dia. but even then they have a hard time with full cutter depth cutting.

If you kept the same size and capibility ratio of milling machine to cutter,the small mills would have only a cutter of 1/4" dia. with a cutting flute depth of only 1/8".

So take it easy.

 

And if you are burning wood,either your speed is too high,feed too fast clogging up the flutes of the cutters,or you have a cutter that doesn't have enough room for the chips created by you cutting speed and feed.

 

Mini mills  EQUAL MINI CHIPS!!!

 

Keith

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Ahoy Mates

 

To start with I am a now retired tool and diemaker who has been using mills of all types for the last 50+ years. What advice I would give all about milling is that,since you are not having to do it for a job with time being a large factor- Take your time milling. Small cuts do two things: 1- it saves wear on your cutters which are costly to replace and 2 nd  it reduces any deflection of either the cutting tool and reduces the over cutting of the mill cutter in your work piece.

 

The small milling machines are not built to handle deep cuts by the milling cutters. In size a standard Bridgeport milling machine handles cutters up to 1" dia. but even then they have a hard time with full cutter depth cutting.

If you kept the same size and capibility ratio of milling machine to cutter,the small mills would have only a cutter of 1/4" dia. with a cutting flute depth of only 1/8".

So take it easy.

 

And if you are burning wood,either your speed is too high,feed too fast clogging up the flutes of the cutters,or you have a cutter that doesn't have enough room for the chips created by you cutting speed and feed.

 

Mini mills  EQUAL MINI CHIPS!!!

 

Keith

Great advice Keith, will keep this in mind for when I start using a mill

Slainte

Peter

Edited by Landrotten Highlander

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I like to add one more thing to the excellent advice by Keith the Bear.

Chatter can occur when you mill at a slow speed. It will create a rough surface.

For milling metals you might also try a lubricant such as some WD40. It is messy but gives much better results.

 

On my mini-mill I usually go high speed with small diameter tools (eg. 5000 rpm for a 1/16 inch bit).

I don't take deep cuts on metals but am not afraid to try increasing depths on wood. 

Burning wood usually means a dull cutter or a wood full of resin. Why pine for small stuff?

Try some pear or birch.

 

Go Bears!

Edited by Modeler12

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Is there a tip available on releasing the cutting bits from the collets?  I have the Proxxon MF70 Micro Mill and am still learning with it...........the bits are difficult to remove and change out once a task has been completed.

 

JP

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The most common way is to loosen the collet from the top with a wrench that can turn the spindle. You hold the collet while loosening the spindle. Then you may have to give the spindle a tap with a mallet which should drop the collet down. You can then continue to loosen the spindle until the collet drops into your hand.

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Hm, gently push the bit up after untightening it - and it would be released.

The reason why it gets "stuck" is because the collet is getting squeezed into the chuck when you tighten it.

Never tried to hit my mill with a mallet, that sounds a bit rough :)

MF70 is a tiny mill that looks quite gentle. 

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The collet drops out of the spindle with ease after loosening with the wrenches but the cutting bit seems stuck inside the collet..... just don't know if I'm missing something when it comes to releasing the bit from the collet??... which always seems to be difficult ........grease the collet perhaps????

 

 

JP

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The collet drops out of the spindle with ease after loosening with the wrenches but the cutting bit seems stuck inside the collet..... just don't know if I'm missing something when it comes to releasing the bit from the collet??... which always seems to be difficult ........grease the collet perhaps????

 

 

JP

I would suspect that either your bit or the inside of the collet has a slight burr. I have never had such a problem.

Can you use a piece of dowel inside the collet to knock the bit out?

When I mentioned the use of a 'mallet' I did not think of using a lot of umpf. 

I have a hammer with a copper head. It must be close to 100 years old and belonged to my wife's grandfather who was an auto mechanic back in the twenties. The hammer does the trick for me.

post-246-0-18879900-1470431814_thumb.jpg

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I've encountered a similar issue JP. My solution was similar to Jay's - insert something of slightly smaller diameter in the other end of the collet (eg a drill bit, or piece of brass/steel rod), and then GENTLY tap the end. It doesn't take a lot of force to free the bind. Sometimes just tapping the inverted "assembly" on the workbench top is sufficient.

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Hey guys,

 

Great topic here, very useful information! I have been looking for some small size end mills and have had trouble finding them for reasonable prices or in decent sets. My question is if anyone knows of a good source for these. I have found some on ebay and micrommark has a few, but just wanted to know if there is a hidden gem out there for them. Size of shank doesn't really matter as I have a 3/8" end mill holder as well as a set of collets that go down to nearly 0 gap. Thanks in advance for your input.

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Here, in the UK, the cheapest (inevitably) come from China, but the quality is acceptable if you are prepared to wait a month or so for delivery.

Many are labelled "PCB Mills" (Printed circuit board) for the electronics market and can be found on Amazon with standard 3.2mm shanks and a mill size down to 0.25mm.

The price can be worryingly cheap - around a tenth of that of UK suppliers- but, with care, they work well.

Below 1mm dia I have only used them as drills, above 1mm they perform well as mills.

 

Ken

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Hey guys, thank you for your responses! These are about the prices I have been seeing, I might just have to bite the bullet and buy a handful at about $13 each. Good call on the dental burrs, I hadn't thought of that. I will also check out your Proxxon catalog to see what is available.

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On my current build I needed to mill a slot on a curved piece.  I saw this idea in a build log a while back - I made a table for the mill with a small a peg in it.  By keeping the workpiece pressed against the peg and moving the workpiece towards the cutter I was able to mill the slots I needed.  It's best to make a series of light cuts, rather than trying to mill off everything in one pass.

 

58b4d4455c37d_4MillingTablesetupforcurves.thumb.jpg.c4adc44cd1ff0ca5a3a92993093b82d6.jpg58b4d46a8f525_5MillingtheKeelsonbottom.thumb.jpg.5f6f6923d8e59ca1781683f421ae09db.jpg58b4d47087a6f_6KeelsonBottom.thumb.jpg.370d6cfa0cf2d0b4fffb55dd804d1f12.jpg

 

 

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On 13/09/2015 at 2:54 AM, Modeler12 said:

Yes, Frank, I am familiar with these nuts and have used them in the past (although the ones I have are 1/4-20).

 

Meanwhile I have added a couple ball bearings on the fence. Using the same piece of wood as before (1/8 x 5/32 basswood), I routed it and it was very easy to push through with no chatter or up and down variations.

There is a small nut on the back side of each bearing to hold it in the slot. I am limited to about 3/8 inch vertical but for any wood that thick, I don't think I have worry about using the hold down feature.

post-246-0-96636300-1442076286.jpg

In the picture you can also see the slot in the table as well as in the metal guide. That way I can move the whole thing back and forth about 3/4 inch. It goes to show that there are different ways of doing things like that.

 

.....two years later, I finally got around to making my own router table for the mill. I have basically copied Frank's (Mahuna) and Jay's (Modeler12). I used a piece of Melamine covered shelf for the base as it will give a nice slick surface to push stock over. The fence is 3mm aluminium angle. There are Sherline cap-screws through both the fence and on the main board that go into the mill table T-slots. For the "finger board" I used a piece of Delrin - the two screws go into T-nuts as per Frank's design. I didn't get around to adding the ball bearing "hold downs" as Jay has done, but I may get that soon. It works like a charm. Thanks Frank for your original post on this - sorry it took so long to get around to copying it!

 

59c78f6a7867d_1MillRouterTable.jpg.f1786ec7a57b3374b26d45e5ec56e8c8.jpg

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