[JoshGrrrr]

That's how the one I use is. I love that everything is electric instead of geared.

Our's reads 5 millionths, but holding that tolerance with is another story. Holding a .00005 tolerance with anything other than a precision grinder can be extremely difficult.

[motoman13]

the guy i know and work for his hardinge cost him about 45 grand, but then again he had alot of differnt options and custom painted

[nelspot 007]

The turret lathe is a hardinge "cobra" don't remember what it cost 50 to 60 I think? but it will hold 5 mil! God only knows why you need to machine that tight...lol. A good warm day and alloy expands more that 5 mil...

[ojhspyro89]

Psh, screw them machines that can hold 5 Mill. I enjoy the ones that can hog a 1/2" off in one pass.

I enjoy the Cincinnati's that my dad has at work. I could sleep on the bed, with room to spare, its huge.

And ill have to get some pictures up of my cute little mill, Ill get some pictures after school.

[JoshGrrrr]

I do that with a bridgeport. I've actually stalled a bridgport out once. I had a 1/2" z-carb cutter buried up to the top of the flutes cutting a slot through a piece of tool steel all in one pass. I was doing about 1500rpm with no coolant at all. Needless to say, the chips that were flying off were that cool purple color. I did it just to prove a point. I kept suggesting that some of the students get a few good carbide endmillls, they didn't think it was worth the extra money. I was trying to show them how carbide can remove MUCH MUCH more metal without the cutting edges getting burned up like HSS does.

[nelspot 007]

Don't know if you guys have tried it yet but carbide router bits like rounding over and bevels (for wood) work well on alloy if your mill can turn em fast enough (4g minimum). Slow feed rate and little passes cause they only have a 1/4" shank. But saves time if the contour you want to get is a standard router bit size.

Josh...one of our guys friction welded a HSS end mill into a chunk of D2 and snaped the 1/2" shank. We keep it on the wall as a trophy!!!!!

[JoshGrrrr]

I've seen kids sling 3/4" end mills completely across the shop by trying to climb mill on a bridgeport.

BTW, they they sell radius cutters meant for metal. Why not just use those?

[Nick E as Ungodly]

Originally Posted by nelspot 007

Don't know if you guys have tried it yet but carbide router bits like rounding over and bevels (for wood) work well on alloy if your mill can turn em fast enough (4g minimum). Slow feed rate and little passes cause they only have a 1/4" shank. But saves time if the contour you want to get is a standard router bit size.

Josh...one of our guys friction welded a HSS end mill into a chunk of D2 and snaped the 1/2" shank. We keep it on the wall as a trophy!!!!!

D2? isn't that the steel you use for the cutters on lathes(the "blank" tooling you grind to shape)? Have a few(actually, tons, but only a few are out of storage) and they're crazy hard. they will cut glass fairly well though

[JoshGrrrr]

It's tool steel. After it's heat treated you can use it to cut some metals.

I don't think tool bits are the same alloy. I think they are a harder alloy. You really can't get D2 any harder than the low 60's in the rockwell scale.

[Dude5779597]

Well Im just wondering what exactly makes you qualified to write such a thread? I am not bashing in any way, shape, or form. I am just wondering.

Like are you a machinist or something like that?

[Dead_Body]

Originally Posted by Dude5779597

Well Im just wondering what exactly makes you qualified to write such a thread? I am not bashing in any way, shape, or form. I am just wondering.

Like are you a machinist or something like that?

Been a hobbyist and made a bit of part time money from it doing some jobs here and there since some point in the mid 60's.

I can remember standing up on a wooden box to turn the wheels on my Dad's big ol' Southbend. At that point it wasn't about making anything and I was likely around 8 at the time. I later made my first actual part for something related to my model airplanes at around 12.

[Dude5779597]

ahh I thought maybe you had some formal training. Well its all the same in this case pb milling is usually pretty basic. god job on the thread btw. Maybe you should throw in something about my favorite mill, the bridgeport .

[JoshGrrrr]

Originally Posted by Dude5779597

ahh I thought maybe you had some formal training. Well its all the same in this case pb milling is usually pretty basic. god job on the thread btw. Maybe you should throw in something about my favorite mill, the bridgeport .

This thread is intended for people who are trying to get into milling. We have people constantly making threads in here asking about mini mills. This thread is to help clear that up. I doubt many kids on PBN who are trying to get into milling have a place to put a 2000+lb machine, the money to buy it, and either 3-phase power or a phase converter to make it run.

I asked him to make this thread. Of all the people I see throwing around machining advise in these forums, he seems to know what he is talking about more than everyone else. I have formal training. I have a degree in Precision Machining/CNC Machining. I am also a part time instructor at a technical college. I could have made a guide, but it wouldn't have been any better than this one. Dead Body knows his stuff. He's definately willing to put more work into a guide than I am.

[lifelessimp]

Very nice guide . Very useful information.

[nelspot 007]

Originally Posted by JoshGrrrr

I've seen kids sling 3/4" end mills completely across the shop by trying to climb mill on a bridgeport.

BTW, they they sell radius cutters meant for metal. Why not just use those?

Ohh I know they make em for metal, but you can get a cheap set of radius cutters for a router for about the same price as one good one for metal. Since the shop hasn't got the the size radius cutter I needed, I bought a set to try. Worked nice!

Lathe tools are normally M2 steel D2 is used for making dies, not as hard but better shock load and wear resistance than M2

As far as my qualifications go, My father is a metalurgist and a machinist he started he own shop when I was in highschool. Like "Dead_Body" I have no formal training. But have been working/running a machine shop for over 20 years now. Been making parts for my markers since 1984.

[courter_man_08]

i don't know if its been posted...but heres the way to find your RPM (speed) and your IPM (inches per minute, feed)

RPM= SFM (on a mill its 60, lathe its 40) times 4, divided by the diameter of your cutter

IPM=RPM x CPT(chips per tooth,0.003 for high strength steel) x by # of flutes (cutting edges on the cutter)

this is only my first year in precision machining class so im still learning the tricks of the trade.

[Dead_Body]

And important info it is too. There are also charts out on the web for fpm vs rpms for various cutters. The charts are intended for end mills and work well for that.

A little trick is that you can use the same charts for the lathe. Just use the cutter diameter as the diameter of your stock and try to set the RPM's to around 2/3 of what they say. I say 2/3 or so for two reasons. Those charts are all about speed and money and to hell with the cutter lifespan. But for hobby work the tooling is often happier at 2/3 to 3/4 of what the charts say in terms of easing up on the machine to avoid chatter and cutting edge life and since hobbyists don't use full flow coolant feeds.

[Dude5779597]

Originally Posted by JoshGrrrr

This thread is intended for people who are trying to get into milling. We have people constantly making threads in here asking about mini mills. This thread is to help clear that up. I doubt many kids on PBN who are trying to get into milling have a place to put a 2000+lb machine, the money to buy it, and either 3-phase power or a phase converter to make it run.

I asked him to make this thread. Of all the people I see throwing around machining advise in these forums, he seems to know what he is talking about more than everyone else. I have formal training. I have a degree in Precision Machining/CNC Machining. I am also a part time instructor at a technical college. I could have made a guide, but it wouldn't have been any better than this one. Dead Body knows his stuff. He's definately willing to put more work into a guide than I am.

Well I wasnt bashing I was just wondering.

Also compared to the high end mini mills that he posted brisgeports are quite close in machine cost($1000). Although that price is not obtainable for alot of people out there, if you are in an industrial area or a previously indutrial area then they are quite easy to find used. As for the power most homes have a large outlet, that the bridgeport uses, for dryers and then its just a matter of running wires. Realy only space is a tough issue to overcome.

And I dont mean any off this out of disrespect or something of that nature I am just representing those, like me, who are fortunate enough to live close to industrial areas.

[JoshGrrrr]

Bridgeports don't use the same plug in that dryers use. They use 3-phase power. In most places you can't even get that in residential areas. Special power lines have to be used for 3-phase. In most areas, if you live more than so many feet from existing 3-phase power, you have to pay for every foot of line to get power where you need it. You have to use a phase converter to use a bridgeport on single phase. They work fine, but you lose 1/3 of your horsepower.

If you can get a bridgeport for $1000, buy every one you see. I've worked in several shops. The cheapest I've ever seen a bridgeport sell for was around $1500, and that's for piece of crap machines that take a lot of work just to get them in working order. Money is only a small part of why a Bridgeport is completely out of the question for most beginner machinists. They have nowhere to put a machine that large and heavy. It has to be on a concrete slab. They have no way to transport it or move it and they don't want to or don't know how to use a phase converter.

[Dude5779597]

Originally Posted by JoshGrrrr

Bridgeports don't use the same plug in that dryers use. They use 3-phase power. In most places you can't even get that in residential areas. Special power lines have to be used for 3-phase. In most areas, if you live more than so many feet from existing 3-phase power, you have to pay for every foot of line to get power where you need it. You have to use a phase converter to use a bridgeport on single phase. They work fine, but you lose 1/3 of your horsepower.

If you can get a bridgeport for $1000, buy every one you see. I've worked in several shops. The cheapest I've ever seen a bridgeport sell for was around $1500, and that's for piece of crap machines that take a lot of work just to get them in working order. Money is only a small part of why a Bridgeport is completely out of the question for most beginner machinists. They have nowhere to put a machine that large and heavy. It has to be on a concrete slab. They have no way to transport it or move it and they don't want to or don't know how to use a phase converter.

I have seen them for around $1000-$1200 range, but even at that bargin price I could not justify getting for just home use. While I have never hooked up my own bridgeport but I've noticed that they used a similar plug as clothes dryers, but I never realy looked into the power source that deeply. You can get them on ebay for that price also, but transporting it or shipping it would cost alot for those not close to the machine.

My original point was that bridgeports are my personal favorite and it is completely feasible to get one if the proper preparations are made. I learned on one of those hulks and will always have a preference for american iron.

[JoshGrrrr]

I learned on a Bridgeport as well. It's what I prefer also. I was lucky. The year I started school they got 6 brand new ones. Using a nice, new Bridgeport is so nice. The place I work at now doesn't own a single Bridgeport less than 40 years old. Once you get used to the good stuff, the older belt driven ones suck.