Showing posts with label mill. Show all posts
Showing posts with label mill. Show all posts

Tuesday, February 17, 2009

Turning on a...

Ok, this might be exciting if it was the first thing that I ever turned on a lathe, but it isn’t. I don’t own a lathe…


_It is_ the first thing that I’ve ever turned on the Bridgeport mill. Basically I set it up with an R-8 arbor mounted 4” lathe chuck, and then clamped a lathe carbide tool in the vice and used the quill downfeed to feed it past the lathe bit, the setup looks like this:


FWIW, that finish was the result of a .027” depth of cut. I intended to do another clean up cut, but when I measured the piece that it was supposed to press into I made the mistake of measuring a scrap of the pipe that was cut off next to a weld so it measured smaller than a new piece of the pipe (for those of you that don't know, welding ‘shrinks’ the piece), so I ended up with the fit that I wanted without the clean up cut that I thought I was going to make. Otherwise, it was done with the Bridgeport head pulleyed all the way up (2850rpm), but with the VFD set at 10hz, making it roughly 475rpm (the heavy cut was interesting because you noticed the torque management on the VFD kick in as it hit the heavy part of the cut to maintain the set speed).

What’s really neat about about this setup is that since the Bridgeport table has a DRO on it, I can quickly cut identical diameter parts just by zeroing the X axis and feeding the table over (effectively, feeding the cutter in) till the DRO shows .0000”. I can also cut any angle relative to it that I want by rocking the Bridgeport head over to the angle I want to cut and using the table Z axis feed to make the cut.

If anyone is wondering what it is, I couldn’t find black iron threaded caps big enough to cap the ends of some pipes, and the store couldn’t thread that pipe size either, so instead I found caps that almost fit inside the pipe and am going to press them into the end of the pipe with the press and then weld them in to seal them up. That will look a lot neater than threading on caps anyway. When they’re done they’ll get a couple of fittings welded to them and a valve added to the bottom and be used as moisture separators/drains for my air lines.

Saturday, December 27, 2008

Effective Uses Of The Bridgeport Type Mill – Precision Measurement Supply

I ran across this instructional video trying to find info about cylinder head milling fixtures online, and ended up renting it from Smartflix for $26… advertized as:

"This Three Volume Video Series Is Loaded With Tips On How To Get
The Most From Your Bridgeport Type Vertical Mill"

With a retail price of $80… you kind of expect something at least semi professional, ESPECIALLY since these guys have a whole series of instructional videos. WELL, that's not what you get. The rest of this post is a slightly edited version (mainly to remove/fix context specific stuff to make it make sense on it's own) of what I posted as a review on the smartflix site, which I somewhat suspect won't get posted because of being long and critical, we'll see:

On Smartflix site you can give a video 0-5 lightbulb, I gave it 3. I have to emphasize, for the most part this DVD set is such a hideous turd that there had to be something good here to get me to rate it anything above a 0, so I'll start there.

The good:

  • He does give some different and useful approaches to common automotive problems. Other reviews have called it "meatball machining," but I will argue that there are times that you do what works best, and if it's not the "correct" way of doing it, well you live with it.
  • He does give some OK advice on what accessories are good places to spend money for your mill.

The bad:

  • They're listed as 3 x 90 minute DVDs??? Did I get the right ones? They all have big long dead spaces at the beginning and especially end and I finally actually tried checking the time on the actual content and got under 50minutes for all of them, I think the shortest was just over 36minutes if I remember right. This should be a SINGLE DVD, and charged as a single DVD rental.
  • Probably close to 1/3 of the total content is an advertisement for PM's products. I mean common, "here's our headholding fixture…" "here's our flycutter…" "we're going to use our alignment tool again…"
  • Ok, I'm willing to overlook a lot for good technical information, I mean, put a guy in a shop with a DV cam and I'll watch it if the info is there, but this is a bit ridiculous. The sound level is roughly 35-50% of what it should have been set at (if you're watching this on a laptop with wimpy speakers it becomes a real problem), there's tons of noise, especially in the 3rd dvd and the picture leaves almost as much to be desired as the audio. Again, I'll put up with all sorts of cruft to get good info, but at the price that they're charging for this thing selling a few DVD's would pay for equipment to produce _much_ better quality output. Along these lines, I can deal with a dog walking in and out of the picture, or our "host" stammering a bit and figuring out where he's going with what he's talking about, but, come on, you couldn't stop for a 30 seconds to let the ice cream truck pass so you're not trying to talk over the music???

So, did I learn something? Well, yea, I think I did, but most of what you see on YouTube or similar sites is better quality. It's really a shame, since it's obvious from watching the host of the video (I believe his name was Adrian Pendergrass or something similar from listening to the introduction) go through the his motions that he's quite familiar and comfortable with what he's doing and has some good information to share.

Monday, November 03, 2008

2300 Pounds of Good Karma

I keep hearing it… “tools are good karma.” Ok, damnit, I need some good karma.

To that end, I brought home a whole big pile of karma yesterday. Actually I made a deal on it on October 22nd, but wasn’t able to get it moved till yesterday. Man was the waiting hard. All the while Deker reminding me that “with a mill you could be dangerous…” (note: I can be dangerous with a dull spoon, but I know what you mean).

Anyway, here she is sitting in her orginal home, a Bridgport J-head, with a DRO, power feed on the X and Z, and a bunch of little stuff added in:




The original owner, John seemed like a really decent guy that had a good thing going, those pictures are taken in his home shop, he’s a CNC machinist for a defense contractor but makes those brackets that hold street signs to the cables over the tops of intersections out of his home shop. I always thought that there was some big company somewhere that did that, but as far as I can tell he supplies most of the mid atlantic/east coast.

I was in a weird position trying to negotiate a deal. First he started at a really decent price, after a little bit of discussion he immediately came down $25, that was it, but the longer we talked the more little bits of tooling… he added to the pile (the stack of stuff on the table was where we started, he ended up adding a few things). He finally added a cool but worn, modular shell/face mill to the assembly and Deker sort of sealed the deal by saying something like “well even I’ll have to say that that’s worth more then whatever difference we were talking about.”

Anyway, when I showed up to pick it up, what I thought was John’s negotiating technique (instead of going down in price, adding goodies to sweeten the deal), well I’m not sure what it was. Part of it was clearly that his new CNC setup used a different collet size so he had no use for anything with a standard R8 collet, so he kept adding whatever R8 stuff that he found, including a few drill chuck collets and other goodies. Some of it was he was cleaning stuff out and figured he could get rid of it and I might find it useful (along those lines was a big, relatively heavy steel cabinet with shelves in it, similar but slightly heavier to one that I already had in the basement from when a friend of mine got me in to help liquidate some of the equipment from a bank’s server room), and some of it seemed to be him just helping out someone just getting into machining (a few things that he added like an indicator set and holders…).

The cool thing about it is all the goodies were that they were mostly good, old school, American made stuff by the major players, with the only exceptions being the Sandvik Modumill (the shell/face mill, they’re made in Sweeden), the enco hold down set, and the vice was a knockoff of a Kurt type vice.

Deker hooked me up with a friend of his, Tige, who is also a knifemaker/blacksmith that works as an equipment rigger, and we made arrangements for him to meet me with his truck and equipment (and wife, I could only guess that she was bored) to move it.

Loading it was basically the opposite of unloading it with the exception that John had a John Deere with a set of forks and had already gotten it out of the shop.

Anyway, here’s the mill in the truck with Tige. A couple of interesting things here, first, those little dolly’s/lifts are really cool, a 2 piece steel frame that slides over itself with a bottle jack that lifts the claw half of the frame. Once you strap the 2 of them on there you can roll it around fairly easily. The second thing is check out the strap holding the 2 together, as well as the rails in the side of the truck… all of his straps had some quick snaps that snapped into those long rectangular holes in the sides of the dollies and truck rails. I think that I’ve seen those in moving vans, but I’ve never seen the straps that match them:


Here’s me acting as a counter weight… my fairly steep driveway was actually the biggest problem we had. It doesn’t look like it, but I’m pulling pretty hard just to keep it in place on the liftgate. In the truck we tried muscling it around and with Tige pushing and me pulling we weren’t able to move it at all, but he could prevent it from rolling. With me pushing and him pulling we could move it a few inches at a time, but after getting it to move a few inches I couldn’t stop it from rolling back to take a break. Part of the problem was that one of the 2 dollies had a wonky caster that didn’t want to straighten out, but in the end we finally gave in and had Christina grab the come-a-long out of the truck and we hooked that to a strap around the mill and around the end of the tailgate. Once we got it moving we were able to yank it back onto the liftgate (you can see where I kicked the strap/cable puller over to the side/of the liftgate):


A note for anyone that gets stuck doing this sometime: A bridgport looks like it’s going to be back heavy with the big cast iron base on the back of it. Turns out it’s actually very front heavy since the base is hollow, but the knee, table and head are big, solid pieces all hanging off the front. Every time we shifted, lifted it, bumped it over something… it tried to flip over frontwards, and I’d bet that if it went more than a couple of inches before you caught it there’d be no catching 2300# or so of top and front heavy cast iron from flipping over. If you’re thinking “simple, crank the knee down and table back against the column, you can even crank the head back or flip it to lower the center of gravity…” Well, that would work if you were lifting it with some forks under the head assembly, but the dollies and levers we were using we had everything as far in those directions as we could get away with. The plumbing for the one shot oiler and the rails for the DRO were in the way.

A couple of pictures of it in place… since I’m putting a deck on the back of the house I gave up on trying to wedge it into the basement, not that it couldn’t go in there, but I don’t think that I could get it back out with a deck over the basement door. I also don’t think that the basement floor would support it. I kept having people tell me that the normal pour, roughly 4” slab down there would be fine… well, the slab in the garage is something on the order of 8-12”, reinforced with a fairly tight mesh of rebar and I swear you could hear it move and shake as we levered it off the wood that we set it on to get the dollies out. Finally setting it down felt a lot like what I imagine a shock from an earthquake would feel.




Another note for those out there moving/acquiring a bridgport… they list them somewhere north of 2200#, I’m guessing that with all the options this one is around 2300-2400#. The other thing is that they take up a lot of space, you need roughly 6x6’ worth of floor space and most sites list them at 82-83” tall… that is for the standard motor models… ones with a pancake motor like mine has is much shorter, right around 76-77”.

Anyway, anything this big probably needs a name, but I don't really have any good ideas yet...