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Short milling cutter versus long milling cutter


ElgaKoster
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I found a place ten minutes from my home that sells the Swedish company Seco's milling cutters...but they are rather expensive!

http://www.secotools.com/en/Global/Products/

My one problem with the Proxxon 1mm cutter is that they break quite easily, on the Seco 1mm cutter the bit that cuts is only 2mm long as opposed to 12mm on the Proxxon and somehow I think the shorter one is less likely to snap off. I generally use this cutter for 1 to 1.5mm deep mortises, have anyone used any this short, here is a screen shot of the technical data.

post-6-0-52151200-1438772739_thumb.jpg

Niels send me a link to a German company, on their 1mm cutter the cutting part is 5mm long, one thing in their favor is that they are quite a bit cheaper than anything else I have seen.

http://www.as-toolstore.de/epages/62215969.sf/de_DE/?ObjectPath=/Shops/62215969/Products/%222320%200100%200500%22

Any input? I would happily pay for the short one if it is going to last and not just snap off as easily as the long one does.

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Hi Elga, I have been studying Gravers - the process of creating, sharpening and using gravers.  A couple of the guys from a lathe forum have been sent me DVDs / VHS to borrow... and per my notes from watching the W.R. Smith DVD indicates the following about High Speed Steel:

 

Tungston Carbide Chips easily and is the hardest

Super Colbalt M-46 Steel is next hardest

Cobalt Steel M-33 is 5% Cobalt

 

He indicates when sharpening / creating a graver shape, if it starts to glow and you put it in water to cool, it will make it brittle.... so understanding the properties of the mill you purchase may be of some help.  I was looking at drill bits and mills last night at MSCDirect, and there are pages and pages --- The mfg should include specs.

 

I'm sure that if/when you were cutting metal, that you used a lubricant to reduce the heat--- but if one of your students used your mill, perhaps they forgot the application of lubricant.

 

As usual you are ahead of me - so I'm sure that someone else will have a better recommendation for the kind / brand that you can purchase. 

 

It is good news that you have found a resource close to home!  No Shipping, and no waiting for a package to arrive!

 

Tamra

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Tamra, I use this specific milling cutter for cutting mortises in wood, I am not sure what metal the dental burrs are made of but have seen the milling cutters only in carbide.

We do use it in our club and the students do break them and at about $18 a cutter that is hard on the club, it is a community club, the teachers teach for free and generally donate the kit as well, the small fee that the members pay for the kit and attendance all go towards buying tools for the club.

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Elga,  When I get down to those sized I go for Tool HSS bits. My experience is that carbide snaps too easily.  Unless you have a very high quality milling machine to run them in. Drill presses are the least rigid of machines to  use for milling cutters (although drill presses have been used of years in the miniature making world).  Also HSS milling cutters are at least half the price or less.

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It might be getting harder to get HSS steel baby end mills as most are now made in carbide. What i want to know is when during the cutting of the mortice are they breaking them? it might be a technique issue? Also are you sure you are using "end cutting" end mills? not all are. Also what speed are you running? it should be a fast as possible. And what machine are you using?

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Bill, I think it is just due to carelessness that the cutters gets broken, in my own case at home usually when I am tired and lose concentration. The cutter we always use is this one from Proxxon, if it is an end cutting end mill or not I don't really know...

http://t.homedepot.com/p/Proxxon-1-mm-Tungsten-Carbide-Milling-Bit-28758/203459726

The machine we use are the Proxxon micro miller MF 70 and we do use it on a fast speed.

http://www.proxxon.com/us/micromot/37110.php

I found the HSS steel end mills at the places that Bill H mentioned, the only problem with them is that the 3/16" shank is too big for the Proxxon mill. And what I find interesting is that on these the cutting part of the bit is very short too.

I don't have a mill of my own yet, I have been using one of the two that belong to the club...when I do buy a mill for myself it will be the Sherline, I think the Sherline can handle more and the motor is a lot better too in my opinion.

All in all I have decided to get one of the end mills from the place here, at least the catalogue gives you all the specs and what kind of cutting you can do with the different cutters, Marie Källberg priced them for me in Sweden yesterday...and they are actually cheaper here...

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I love my Sherline mill.  I wish it were just a little bit larger.  I added a headstock extender to give me more throat depth. They  now have a deeper spacer which adds 2 1/2 inches. I might consider getting the new spacer but right now I had to buy new replacement parts. This mill is my third or fourth Sherline mill.  The first one had brass ways instead of steel.  At one time I had a dealership to sell Sherline so I kept myself updated.  Then Sherline decided to eliminate dealers so I quickly up graded to the mill I now have.  I donated my  old one to the GS. I have had this mill close to 30 years and am finally needing to repair it. I have worn out the x lead screw and brass nuts. I have a new screw set coming. It is a good idea to use different parts of the table to spread out the wear. I have also been sloppy in not taking it apart and cleaning and lubing the under surfaces and tightening the tables and lead screws. The mill now comes with oil cups.

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You can buy the small milling cutters from china, less than 2usd each: http://www.ebay.co.uk/itm/10pcs-PCB-cutters-end-mill-engraving-CNC-router-tool-bits-0-3-3-175mm-Select-set-/151730691961?var=&hash=item2353da9f79

 

But all the small cutters breaks when you just look at them.

 

The Sherline mill has a max spindle speed of 2800rpm and at that speed you will break cutters more often than you do using Proxxon at 20000rpm.

 

(The best way to avoid breaking small milling cutters and drills is to use cnc.)

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It is good to know the breaking cutters isn't the result of my inept experience - so how much does the CNC application cost vs. the cost of breaking the cutter?  I haven't broke one, yet because I think I need the equipment first that holds the cutter.  See prevention is the key.

 

Sounds like a lifetime of breaking tiny mill cutters is in my future... :rolleyes:

 

Elga, since you are cutting mortises in wood, I think I would purchase a slitting blade for the saw.  I just did this in Pete & Pam's class at the Name Convention last week.  The slitting blade worked so well.    We are so lucky at our Miniature Club... I think we have at least 3 Micro Mark Tilting Arbors and 2 Preacs and a Jarmac Table Saws, and other members have the other less expensive saws, too, so we can easily set up different saws and do a box workshop.  I think we had 12 people in the class and 3 table saws - so with 5 I should be able to manage a box class at mini club--- although admittedly I've never changed a blade in either one of my table saws - I think my instructor inferred last week that I haven't been using my saws enough...(hah!)  he must know me well.

 

Unless you are cutting hard, hard wood, ie Brazilian Rosewood or Paduk, etc, I doubt that you will break a saw blade.   We cut a couple of pieces of rosewood for one of the boxes, and nothing bad happened to the blades.

 

Tamra

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Tamra, I use slitting saws for cutting the tenons on my table saw...that I learned from Carol Hardy in 2011, my first time at Guild School...plus a few other tricks :-)

But for mortises...you either need cutters or chisel them out by hand.

And if a saw blade broke, I don't think I want to be near it, the hard woods do blunt them though...it isn't too difficult to change blades on a table saw, I have done that quite a few times.

Well, I did order one of the short cutters this morning...we will see how long it lasts...should get it by Tuesday.

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Quote :The Sherline mill has a max spindle speed of 2800rpm and at that speed you will break cutters more often than you do using Proxxon at 20000rpm. Quote

 

Sherline developed a high speed pulley conversion kit for the mill and lathe  (same motor assemblies) to accommodate CNC use. I have not installed mine yet. I am not sure how well my spindle bearings will handle it as they were not really designed for high speed.  All the newer headstocks are produced for the high speed.

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Okay...now I wonder...since at this stage I would use a mill much more for woodworking than metal work...is the Proxxon then the better option since there is quite a difference in speed?

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Okay...now I wonder...since at this stage I would use a mill much more for woodworking than metal work...is the Proxxon then the better option since there is quite a difference in speed?

Not if thou get the high speed pulleys for the Sherline. I think the Sherline is more versatile and has more and much better developed accessories.

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Please forgive me, a "mortise & tenon joint", I was having such difficulty grasping what you were doing with a mill to create a wood joint. I think I need more sleep or to think less about miniatures when I'm supposed to be sleeping...  I would use my dremel 210 mounted as an overhead router with a 1/8" shank and 1/16" dremel router bit to make a mortise... for a woodworking joints.  A lot less expensive application then a mill, and infinitely less expensive then software and controllers for CNC for Neils....  I've never broke a dremel bit yet, and a couple of summers ago spent a month of mornings trying different applications to get a chair to stay together; finally did the joinery properly, instead of following the instructions in the miniature book and it worked.  I'm pretty sure I bought the dremel 210 and table for less then $100, probably not even $60...but that was a long, long time ago.

 

Since I am quite new to this milling concept, I was having difficulty with milling a woodworking joint on a mill...

 

But I'm glad that Niels is into CNC machining, he will be leading the way for the rest of us who are working with 40 year old equipment and techniques from the past!

 

Tamra

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A couple of days ago I ran a groove in some grabby aluminum using a 1/16 dia.  long mill cutter, running the mill at its normal high speed ( no high speed pulley) and did not break it. I very seldom break mill unless I get in too much of a hurry and start to hog it.

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Tamra, it all depends on how thick the wood is that you want to put a mortise in, for example if you build a door frame from 5/64" thick wood you probably need a mortise of no bigger than 1/32".

I am not sure if the Dremel stands have depth control, that is a feature that I really like on the mill, you can control the depth very accurately, a lot of the things I make are really small and delicate, the George III dressing table mirror that I posted about the other day, the base that contains the drawers are made from 1mm thick wood with slots 1mm wide and 0.5mm deep for the dividers between the drawers, so in many cases a 1/16 bit is going to be much too big.

When I planned this piece I did consider using a bit thicker wood...until in a Google image search a similar piece jumped out at me as a miniature and when I asked myself why did I know this piece was a miniature I realized it was because of the out of scale thickness of the wood.

For me also laying out the capital for a good mill that will give me good service for the rest of my life makes sense since I do this full time for an income now...when it was just a hobby I couldn't justify the expense, now I can write it off against tax.

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  • 4 weeks later...

I am not sure if the Dremel stands have depth control

The new Dremel drill press stands are not stable enough for fine woodworking. But there is an older model that could be turned into a dedicated mortiser.

 

The vintage drill stand catalog number 225 is all metal and it is stable. It makes a great overarm router as you control the depth of cut and the feed into the material from below. It is not unusual to see this model on Ebay. It has a depth stop as well as a lock for the table height raising feed screw. However the tool holding clamp does not fit modern Dremel motors.

 

On my do it someday list is to 3D print an new tool clamp for the post that will have the thread nose profile for modern Dremel rotatry tools. The vintage motors that fit it can be found but they do not have the best of bearings and bushings in them.  But note that the distance between the center of the cutting tool and the stop screw for table height is only 1 inch. See a photo below of how to gain another 3/4 inch of work space with this drill press.

 

Last year I spotted a brand new in the original box model 225 drill press on Ebay and snapped it up for a portable workshop setup. It could certainly be made into a dedicated overarm mortiser by creating a custom table overlay with an adjustable fence and stops. Here is a photo of it but look further below for one I have setup with a basic MDF auxillary table.

dremel%252520drill%252520press%252520225

The photo below is of one that I bought a number of years ago (not as pretty as the other one). I filed out the tool clamp a little wider to fit my 1970s era 380 Moto Tool.

I  drilled two holes in the steel table top so I could quickly change out auxiliary table tops. I made the auxiliary table fit around the tool post so I could swivel the depth stop over to one side thereby gaining another 3/4 inch of distance to the tool post without hitting the stop screw.

dremel%252520auxillary%252520table.jpg

Not shown is an auxiliary table I made with removable pins for pin routing. There is a hole in the that auxiliary table into which pins of various diameters can be dropped. The custom sized steel pins were turned from steel rod using a lathe to match the diameters of cutting bits. You drill a hole through the table to match the diameter of the rod. The original diameter is left the same at a length to match the table thickness then turn down a length to project above the table to match the bit's diameter. 

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