Thinking about a larger mill...

[rvt]

Hello again!

You may recall this very old thread I made about trying to find a rotary table/chuck that would fit on my mini mill. I've essentially given up with the idea, because my options just don't seem to give me any room to breathe. On the one hand I of course feel stupid, as when I asked about buying a small mill here everyone said to go with a larger one, but ultimately at the time I didn't have much in the way of spare funds, so it's done it's job to an extent.

What I was thinking of was perhaps finding an older mill and reconditioning it as a project with my dad. He's always been into woodwork, and I'm only just venturing into metal work, so with that in mind is this just a bad idea...? Wouldn't want to take on an impossible project of course. If not, what makes should I look out for? And a random question, is it possible to convert an imperial mill to metric?

I guess the only other options would be to keep saving for a much larger mill!

[Davo J]

You can convert a imperial mill to metric easy enough with a DRO.
If you can get hold of a mill that needs repairs it would be OK, but if it has worn ways scraping is a big job that need a lot of precision tooling to do.
The 45 size bench top mills are popular and a lot more rigid and larger than what you have, maybe you could go this way or look around for a used one.

Dave

[rvt]

Thanks Dave. I will keep your advise in mind if I ever do look for one.

Can I ask what you mean by DRO? Sorry, I'm a complete 'newbie', lots of acronyms just go straight over my head.

[Jasonb]

DRO - Digital Read Out. Using either calliper type scales or better still glass scales but can get a bit spendy though it will read metric or imperial at the touch of a button

To convert an imperial to metric you would need to change the leadscrews &nuts and also re calibrate the dials on the handwheels.

Jason

[raynerd]

Digital Read Out - DRO.

http://www.raynerd.co.uk/?p=411

Because the read out on the scale is digital, a click of the button sets your reading to either imperial or metric! They cost about £20-40 a cheap scale to fit (much much more if you got for expensive glass scales!!) and then a bit of time and thinking to fit one to each axis. They are a fantastic addition to any lathe or mill imo! I have my mill fitted and my lathe will be done shortly.

Hope that helps.

EDIT - Jason, finally a question I could answer and you beat me to it 

[rvt]

Arh, I see what you mean now! I agree, they do seem a great addition to any mill, but also a relatively straight forward way of getting an older machine into metric. Many thanks!

[Swarfing]

Guys you could be scaring this poor guy off from doing this??? It can be really expensive when starting out and as much as adding DRO's and dials is good is also not necessary from the off. I would get a mill and use it, most work should be marked up and you can machine to the marks. I agree totally with everybody else but most importantly just get cutting 

[rvt]

Ha! True I guess, but I was just curious about how easy a imperial to metric conversion could be done on an older machine, so it seems relatively straight forward in honesty. Like you say, wouldn't be an immediate addition

Okay, another round of stupid questions :$.

I'm looking at one now, it says it comes with single phase motor fitted but that the original 3 phase is included. What does single and 3 phase motor mean on a mill...?

[Jasonb]

Basically industrial tooling is 3 phase and domestic houses mostly are single phase so the motor has been swapped to allow it to be run in a home workshop. The advantage with still having the old motor is that provided wound the right way you could at a later date run that via a VFD (variable frequency device) to make the mill variable speed without loss of torque.

Jason

[raynerd]

... you could at a later date run that via a VFD (variable frequency device) to make the mill variable speed without loss of torque.

which is well worth it and certainly is an added bonus in buying the mill! I converted my lathe to variable speed with a 3 phase motor and inverter and it was a great add-on.

Swarfing - I expect fitting chinese DROs may be more economical than replacing leadscrews, nuts and handle markings if trying to address the OP's question regarding converting the mill from imp to metric.

[rvt]

Thank you for explaining that for me! That definately seem like an added bonus, running high torque at lower speeds.

What do you think of this one? I was thinking of placing a bid, but decided against it purely because of the weight/distance for collection (It's in Reading, I'm in Shropshire).

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150579367696

[Jasonb]

X travel may be a bit limited and the non standard taper will limit the use of off the shelf tooling.

[rvt]

I thought because of the chuck and collets included the odd taper wouldn't be an issue in real life. But didn't realise the X travel might be short... not sure how short exactly... is this normal with larger machines?

Found this: http://gorton-machine.org:8080/forms/form_1319/index.html

Is this thing really likely to be 1ton? 1000KG? :S

Having a lot of trouble with this site loading BTW!

"Fatal error: Maximum execution time of 30 seconds exceeded in C:\Inetpub\vhosts\madmodder.net\httpdocs\Sources\Subs-Post.php on line 24"
>Load.php on line 1568
>various other codes

[Jasonb]

States 20" travel for the medium 34" table so maybe 15" on the 24" table, bit more than I thought but less than an X3
 
As you wanted to convert the machine to metric I assume you have metric milling cutters which won't fit the imperial collets, you also won't be able to easily fit boring heads, flycutters, slitting saw arbors or any of the usual taper tooling, though parallel shanked stuff in say a 1/2" collet may do you

Weight sounds right as the catalogue says 2200lbs

[Swarfing]

yes my apologizes and you are right it would be cheaper getting DRO's in most cases than scews and nuts. The Gorton would be false economy buy as by the time you bought and sourced everything else you would need you could almost get a new one with extras for that?