Round Column Or Dove Tail

[robwilk]

Hi all i have not been around for a while since my daughter was born in November and i certainly have had no workshop time :shrug:.
But when i have had chance i have been doing a bit of research on milling machines i have nearly decided which one i want even though i don't have enough money saved up yet.
There a few options i am not sure about the first being Round Column or Dove Tail i would love to hear your experiences of each of these options Thank you.

Rob.........

 

[Metal Butcher]

Hi Rob. Below is a link to a recent discussion on the subject. Reading through it will give you a start on gathering the information you'll need to make this very important decision.

I have a round column and would prefer a square column mill/drill.

http://www.homemodelenginemachinist.com/index.php?topic=12738.0

-MB

 

[kd7fhg]

Rob,
I have the Seig X3 square/dove tail column and I have never had a problem with alignment when raising or lowering the head, unlike the round ones.
Rex

 

[robwilk]

Thank you both MB and Rex that just about clears up my problem i now understand the short falls of the round column hopefully i will be able to save up enough money to get what i want this summer.
Thanks again.

Rob.......

 

[kd7fhg]

Rob,
I have found out that if I don't go for my first choice and go on the cheaper option it usually cost me twice as much in the long run.
Rex

 

[milotrain]

Be aware that at machines the size of the x3 and greater you can use the column for Z travel easily in milling processes and below that size you typically need to use the spindle quill for Z travel as the Z hand wheels are in less optimum positions. Using the column's Z over the quill's Z increases your rigidity which is a huge plus for hard metals like stainless and cutters of the Carbide variety. If on the other hand you think you'll rarely use carbide tools and cut harder metals then this is not a big deal.

 

[Omnimill]

I'd agree with the dovetail choice. Also get a machine a bit bigger than you think you'll need as mass and rigidity are important on machine tools.

Vic.

 

[robwilk]

Thanks for your advice i am now convinced to go for the dove tail machine even though it is a bit more expensive.
This is the machine i am looking at.
http://www.chesteruk.net/store/lux_mill.htm

I am looking at this one because it has a totally enclosed oil immersed gear box rather than plastic gears which i know i would have to modify at a later date.

Rob.......

 

[Omnimill]

Looks like a very nice Mill Rob. What taper will you get MT3 or R8? I only ask because I bought MT3 so I could fit Morse Taper drills directly into the quill - something you can't do with other tapers?!

Vic.

 

[robwilk]

Hi Vic
To be honest i am only learning as i go and have no experience with mills at all so the answer to you question is i don't know because i don't know what the R8 is ???
I know about MT 3 MT2 MT1 but have never come across any other so maybe this is a good time to ask and learn. If any body can give a simple lesson that would be appreciated. Thanks .

Rob.......

 

[Metal Butcher]

Looks like a very nice Mill Rob. What taper will you get MT3 or R8? I only ask because I bought MT3 so I could fit Morse Taper drills directly into the quill - something you can't do with other tapers?!

Vic.

Actually... I bought a morse taper R-8 arbor for my mill from Grizzly Iindustrial. Have never found a need to use it since I don't have any reason to buy drill bits with a morse taper shank. I have heard that if you spin a drill, its likely to damage the taper in your machine spindle. Just something to consider.

My opinion is that the keyed R-8 spindle is the most versitle choice.

-MB

 

[Metal Butcher]

i don't know what the R8 is ???
I know about MT 3 MT2 MT1 but have never come across any other so maybe this is a good time to ask and learn. If any body can give a simple lesson that would be appreciated. Thanks .

Rob.......

Rob, this should answer any and all your questions.


http://en.wikipedia.org/wiki/Machine_taper

http://cgi.ebay.com/R8-Morse-Taper-Sleeves-MT2-MT-2-Sleeve-Arbor-Adapter-/390287678576

-MB

 

[Omnimill]

I have heard that if you spin a drill, its likely to damage the taper in your machine spindle.
-MB

MT Taper drills have a tang on them like a drill chuck so aren't any more likely to damage the quill.

While I think R8 is a good commercial choice the ability to fit plentiful MT tooling is probably better for hobby machines, at least here in the UK.
MT taper drill bits often go for a song here at Model Engineering shows and are extremely useful on machines with a limited clearance.

Vic.

 

[Metal Butcher]

MT Taper drills have a tang on them like a drill chuck so aren't any more likely to damage the quill.

While I think R8 is a good commercial choice the ability to fit plentiful MT tooling is probably better for hobby machines, at least here in the UK.
MT taper drill bits often go for a song here at Model Engineering shows and are extremely useful on machines with a limited clearance.

Vic.

Its the opposite here in the USA. R-8 tooling is available from every machine shop supplier, and there is an avalanche of used available for next to nothing and even for free. And all that I use or need is 6 sizes of R-8 collets, a drill chuck with a R-8 shank. and a boring head with a R-8 shank. Very simple and cheap. I would venture to say that almost all of the 'hobby' machines in the US are R-8.

The limited clearance you mention is not any more of an issue with a machine that has an R-8 spindle. A 1/2" R-8 collet is installed to hold a S/D drill giving the same or better clearance that a MT drill mounted directly into a MT spindle. Fortunately S/D drills are also very reasonably priced.

I wasn't aware that the machines with a MT spindle had a provision to hold the drill's tang. I thought the tooling was pulled up with a draw bar?

-MB

 

[Maryak]

I wasn't aware that the machines with a MT spindle had a provision to hold the drill's tang. I thought the tooling was pulled up with a draw bar?

-MB

Normally it is, but take out the draw bar and the tang fits quite happily. If you lower the quill you will find the normal slot for use with a drift to remove the morse taper shank whatever, (sleeve, drill bit, chuck etc.).

Hope this helps

Best Regards
Bob

 

[Metal Butcher]

Normally it is, but take out the draw bar and the tang fits quite happily. If you lower the quill you will find the normal slot for use with a drift to remove the morse taper shank whatever, (sleeve, drill bit, chuck etc.).

Hope this helps

Best Regards
Bob

Hi Bob. I understand the need for a drift slot. That's the only way a MT taper can be removed from a drill press.

If I understand you correctly, the mini mills that come with a MT-2 spindle have both a through hole for a draw bar, and a cross slot for a tang like on a MT-2 drill chuck shank. If that's the case, then installing a drill directly up in the spindle should be safe.

Thanks.

-MB

 

[Omnimill]

Yes thats right Bob. Speaking to an ex machinist at work he tells me R8 was never as popular in Europe as in the USA. He says most new machines made here after the war used "International" tapers - INT 30 and 40 being most popular. I think we get the option of machines with R8 tapers because the Chinese make them for the American market. You can get tooling to fit almost any machine taper over here but I would say from a hobbyists point of view that Morse Taper tooling is more plentiful and cheaper from the type of suppliers I use. I tend to buy from model engineering suppliers and at shows.

Vic.

 

[Maryak]

If I understand you correctly, the mini mills that come with a MT-2 spindle have both a through hole for a draw bar, and a cross slot for a tang like on a MT-2 drill chuck shank. If that's the case, then installing a drill directly up in the spindle should be safe.

Thanks.

-MB

MB,

That's the set up on my mill/drill. If there is no slot a plain steel rod down the draw bar hole followed by a "Judicious Tap" with a hammer should release the morse taper.

Best Regards
Bob

 

[robwilk]

Thank you for the links to that info MB i never thought there were so many different tapers .
I suppose when the time comes to getting the mill i will go for the MT simply because i already have a few tools with the MT on them for my lathe.

Thank you all for your help.

Rob.......

 

[Omnimill]

May I suggest you consider a ER32 collet chuck for your Mill (and Lathe) when you get it. It will make cutter changes quick and easy. The lathe version also allows you to pass long material through the headstock.
They are half way down this page:

http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Collets-Collet-Chucks/ER32-Collets-Collet-Chucks

I was not too flush so I bought a few collets at a time rather than buying a set ;D

Vic.

PS you can also use the collets in a Spin indexer (Stevenson's 5C Indexing Head with ER32 Nut and Adaptor) very handy:

http://www.arceurotrade.co.uk/Catalogue/Collets/5C-Fixtures