Bridgeport Milling Machine

[LandyManLuke]

I'm in the process of repairing a Bridgeport I acquired, I'm new to machining so have a few questions

- Does anyone know a good supply of R8 tooling? i've trawled ebay and found RDG tools, but I'm looking for others too

- What oil should I be using? the Bridgeport has plenty of oiling points so I guess I should stock up.

- Does anyone have any resources for cutting speeds/tool speeds for steel, aluminium etc?

Anyone else got a Bridgeport? any tips or words of advice?

Cheers,

Luke

[longlandy]

E bay is the way forward,even the china junk isnt that bad. Get the collets that go direct into the spindle as the bridgeport suffers from a lack of ram height. A er 32 collet chuck would be good as these series are industry standard now, the days of the clarkson auto lock are over because a lot of tooling is now weldon shank

[vulcan bomber]

Got 3 of these old girls at work..

We use 32 hydraulic oil in all the oil points.

We use an industrial supply place in coventry for our bits them. We might have some old tooling for them that we'd be willing to sell on if your interested....

Cutting speeds and feeds i forgot a long time ago, we just look at tools and go, that looks about right, the interned will be your friend for this info.

[ejparrott]

I use RDG for the R8 tooling for my Lillian (Bridgeport clone), they're very reasonably priced and reasonable quality. I shouldn't worry too much about imperial collets, you won't find you need them much, unless you're into to model engineering like me.

ER32 collets are a good choice, but only really come into their own if you nc the machine. An ER collet will hold the tool at a set length when you take it out of the spindle, an R8 collet will let it loose. There is little point in just having one ER collet chuck, you won't reap the benefit of it, and at over £30 each, you won't want to buy many unless you're really using it, or its nc. Even at work with the other Lillian or the new XYZ machine, we use R8 collets not ER, and that machine is in constant use 8 hours a day 5 days a week.

I have never found an issue with ram height, just drop the knee and you should get 10" on the table easily, you can also get raiser blocks that are 4" thick if you really need more room.

We oil our machines with a 68 grade slideway oil, same as we use in all our machines from the little colchester to my 8' vertical borer.

Get yourself some carbide tipped face mills and end mills, and keep a watch on ebay for the tips. They will work out far more effective than buying throw-away carbide cutters for every job, plus a face mill can cover 75mm, whereas a 20mm end mill is the most you'll likely be able to hold. 75mm is about the most the 3HP motor will drive succesfully.

Speeds and feeds you'll learn as you go, if is throwing sparks or fighting, you're going to hard and too fast!

[LandyManLuke]

Thanks for the info all.

I've been reading about ER collets Vs R8. NCing the machine is probably on the cards for the future, after I've replaced the lead screws with ball screws, there's a fair amount of backlash in the lead screws, and it varies along the length of the screw too.

ER32 collets are a good choice, but only really come into their own if you nc the machine. An ER collet will hold the tool at a set length when you take it out of the spindle, an R8 collet will let it loose.

By this, I think you mean that because the tooling remains locked in the ER32 collet, it doesn't move when the ER32/R8 adapter is removed from the spindle?

I pressure that If you remove the collet from the holder, it'll go loose and the tool will move?

So, to have multiple tools, and not have their Z offsets change, I'd have to have multiple R8/ER32 adapters, and fit (and leave) the tools I use in each adapter, and set the offset etc.

Where is a sensible place to pick up slideway oil?

I shall have a look at carbide tip tooling.

[longlandy]

er collets are standard tooling now due to the cnc revolution in even small shops.They grip much harder, especially useful when using dovetail cutters etc, As for height issue when you have something big on the table or a dividing head those few inches r8 collets can save make it a yes or no job.Riser blocks are good but hard to find and sought after.

Also in using a collet chuck albiet clarkson or er, when doing tool changes your not undoing the drawbar which is much slower

[LandyManLuke]

OK, if the ER holder stays in the spindle, how do the collets hold the tool at the same offset when you change collets/tools?

[integerspin]

OK, if the ER holder stays in the spindle, how do the collets hold the tool at the same offset when you change collets/tools?

Think they mean they have multiple collet holder so they can just swap holders. I have one ER32 collet holder but have quite a few clarkson chucks, so I have to swap collets/tools in the ER chuck, but can leave mills, which are mostly used for finishing and profiling, in the clarckson chucks[the mills are threaded HSS] and I can just pick up a clarkson holder and stuff it in the spindle.

With Er you don't need metric/imperial, i.e a 9-10 works with 9.52 and 10.

If I had a bridgeport I would probably use R8 collets when possible, they are going to be nice and stiff and about as close to the bearings as your going to get. I don't have a bridgeport I have an old ajax with Int40.

Barratts tooling, you will find them online, they sell secondhand tooling[and some new stuff], I paid something

like £16 for new ER32 chucks. I bought quite a few when I found I could flog them on ebay, infact I had him post them

straight to the buyers, I think he uses ebay now;-)

I bought a 25L drum of rocol slideway oil, I did flog litres to people on the forums but don't think I can sell any

more as I will have to buy another drum.

[ejparrott]

By this, I think you mean that because the tooling remains locked in the ER32 collet, it doesn't move when the ER32/R8 adapter is removed from the spindle?

I pressure that If you remove the collet from the holder, it'll go loose and the tool will move?

So, to have multiple tools, and not have their Z offsets change, I'd have to have multiple R8/ER32 adapters, and fit (and leave) the tools I use in each adapter, and set the offset etc.

Correct on all counts. With a proper ER system setup, you have a bank of tools all in R8/ER collet chucks, of set Z offsets, and the NC system will be programmed with those Z offsets, and will automatically apply them when you call up that tool - this offset needing to be changed every time you have to remove the tool from the collet for breakage or sharpening.

If you just use the ER collet chuck in the R8 spindle, but take the tool out of the collet chuck everytime, as has been said, its harder to do because you havent got as much 'brake' ability for unscrewing the collet nut - your hands are in the wrong place. When undoing the drawbar for the R8 you have both hands at the top of the machine, one on the brake and one on the 19mm spanner - easy!

If you're not NC'ing the machine for now, I'd not bother with ER collets, as I said, they're over £35 per holder, plus a set of collets, whereas the R8 holders come in at a much more reasonable £7 each, give or take, and there's really very few sizes you need, depending on your work. For example, even at work, the majority of out tooling, even on the big CNC mills, consists of 10, 12, 16 and 20mm tooling, all on those size shanks. There are occasional forays into 5 and 4mm tooling, but not often, and so why do you need to buy an 11, or 14, or 15mm collet?

One thing I do recommend is a good quailty jacobs keyed chuck - not a keyless chuck - and on an R8 taper, don't use one in an adator (MT to R8). Money well spent on a good chuck will pay dividends. Being a model engineer and a sub con machinist, I have 3, with ranges of 1-10, 1.5-13, and 2-18 - reason being the physical size of the chuck body is sometimes too big to get in to some areas of a job. For most people a normal 13mm chuck will suffice.

When you do want to NC the machine, have a look at Motion Control Products Ltd, thats where all the bits are coming from for my Lillian. I have the advantage that it was already an NC machine so already had ballscrews, albeit I had them reconditioned, but the NC was knacked, so its having new steppers and drives from MCP, and will be driven using my old PC and Mach3 software - have a look for that, its really good stuff. Got a feeling SimonR has some experience with that, could be wrong though, sure I've seen it mentioned somewhere....

Good luck!

[LandyManLuke]

Thanks all, very useful information.

I'll have a look at Motion Control Products, the other site I've been looking at is Zapp Automation.

I've been looking at USB-CNC rather than Mach3, I like that the interpolation is done in seperate hardware, which the PC talks to over an ethernet connection. I think this is a better solution that using the parallel port, and relying on Windows for 'real time' interpolation.

[pete3000]

rdg tools

arc eurotrade

chronos tools

tracy tools

Richon tools (china)

axminster tools

all good places to browse through

[longlandy]

Get a Er chuck if one comes up as they are current and dont use manufacturer specific collets(I like clarkson or osbourne autolocks but they are no longer made),R8 collets can be a pest when trying to machine in pockets where the machine spindle is too larger diameter to clear the sides.If you cant hold the spindle brake and undo a collet chuck at the same time your in trouble!

My experience is in actually owning a subcon cnc/conventional machine shop and having all sorts of nasty stuff to do including second ops on bridgeports and having both tool holding systems is vital.

[simonr]

I've been looking at USB-CNC rather than Mach3, I like that the interpolation is done in seperate hardware, which the PC talks to over an ethernet connection. I think this is a better solution that using the parallel port, and relying on Windows for 'real time' interpolation.

Thought I'd stick my oar in here!

USB-CNC provides a better hardware solution than the Break Out Boards (BOB's) used on Mach 3 and if I were new to this, I'd probably go down that route based on what info is on line. However, the two bits of software are intended to be used in quite a different way.

On my Mill, I use a PC with a SmoothStepper board connected by USB and this in turn connects to two BOB's One is a CNCDrive servo controller and the other is just a board with 8 relays (main power, coolant, spindle etc) I also have a Gecko Stepper driver connected to some of the spare OP's on the Smoothstepper which drives my 4th Axis.

The Smoothstepper provides the same functionality as the CNC-USB board - but comes with a Mach3 Driver. It's not a perfect solution as it's very suceptible to electrical noise. When affected the machine just stops - which tends not to be damaging but is annoying. To get it going again you have to re-start Mach3 which means you loose the position of your Axis and have to re-clock it to the job before you re-start the program. They say they will handle problems like this better in future - but it doesn't seem to have happened yet. However, it's quite rare so just a niggle.

If I were to use CNC-USB, I would still need a relay board as the outputs are not capable of switching decent currents or voltages. The Servo Drives would plug directly in to the board - so I would only really save one board (the interface between the Smoothstepper and the servo drivers).

So hardware wise, not a lot to call it.

Before I did my first conversion, I figured I would use the machine by programing it directly in G code and / or using CAD CAM. Some of the time that is how I use it, but mostly - and this is where Mach3 wins in my opinion - I use the built in wizards.

There are wizards for most of the things you generally want to do such as milling pockets, circular bolt patterns, arcs, shapes - and on the lathe: facing, boring etc. OK, there are G Code 'canned cycles' for most of these things but you have to remember the parameters. A wizard which prompts you for all the parameters and shows you what they represent makes it much easier.

For most jobs, I just string a load of these wizards together to make a job. It means that the machine is as useful and quick on simple jobs that would usually favour a manual machine as it is for complex jobs which can only be done on CNC. It makes a good hybrid of a Manual & CNC machine.

The CNC-USB software does not have any equivalent to this. Sure you can jog the axes but I have found this is not as driving a manual machine with hand-wheels. I suppose it's like the difference between driving a car using the cursor controls on a keyboard versus a steering wheel. Both are possible but the wheel gives you more finesse.

I would say that Mach3 gives a much more usable interface for the kind of jobs most people want to run on machines not being used for mass production. CNC-USB has been geared to people wanting to do routing, and engraving or milling graphics in to things - hence the import options. The kind of thing you cannot do freehand. However, if you for example needed to peck drill 33 holes in a circle (as I did this weekend) it's much easier to use the wizard than write the code or to draw it on the CAD then get the CAM to generate the code.

This was for an electronic speedo pickup.

Si

[ejparrott]

reason being the physical size of the chuck body is sometimes too big to get in to some areas of a job.

A thought occured, you may or may not be aware that there is a range of ER collet sizes, we have and use ER16, ER20, ER32 and ER40 at work. The ER16 collet chucks are smaller and can reach tighter areas, than the ER40 collet chucks. How much this matters depends on the type of work you want to do, as I said before.

[mickeyw]

Luke - my Bridgeport came with a manual , I'm sure I could scan it if you fancy a copy.

I bougth a 5 gal err 25 lit can of slideway oil on the bay. It's not the same name and number as the book mentions because the lube grade naming seem to have changed since the book was written, but it is an equivalent and suitable for the job in hand.

I have R8 tooling for mine, there's one plain collet chuck, and a small Clarkson Autolock (<16 dia shank) which covers quite a lot of options. As well as a number of fly cutters which I love for ally, there's a smallish interchangeable insert cutter for shifting larger amounts of metal, good for blocking up operations.

As for speeds and feeds I tends to go by what my experience (15 years in toolmaking) tells me is right. When I was at college one of our lecturers tipped us all to write, (yes an actual letter) to Dormer tools, requesting a small reference handbook they produced for free. The people at Dormer must have hated our lecturers for this , but the book is really good. It has speeds, feeds etc for various materials, thread data, tapping drill sizes etc, bit like a Zeus book but with extras. I still have it in my toolbox

I'm sure there's probably a similar online resource for this now, but production cutting tools have changed so much. The machining most of us (except Si) get upto in our garages, tech-wise, is more akin to what I learned as an apprentice.

Good luck with fixing your machine up, you've made a great choice.

[ejparrott]

My machining, being a model engineer, is the same as I do at work.....some times I wonder.....

[longlandy]

A thought occured, you may or may not be aware that there is a range of ER collet sizes, we have and use ER16, ER20, ER32 and ER40 at work. The ER16 collet chucks are smaller and can reach tighter areas, than the ER40 collet chucks. How much this matters depends on the type of work you want to do, as I said before.

I believe er32 is the limit for r8 with a 20mm max collet size

[longlandy]

I forgot to mention ,one thing really worth having is an adapter to take rotabroach bits. With that even the humble bridge port can pop a 50mm hole with ease

[vulcan bomber]

One thing i'd add is that for mucking about i the garage, carbide tools are not worth the cost, you cant get the RPM from a bridgeport to reep the benefits of it. Carbide doesnt grind as sharp as high speed steel either so high speed steel tools will give better finishes and easier/cheaper regrinds.

Tool storage is important.. If you bounce tools around the floor, throw them into a box full of other tools, they wont be sharp for long.

[simonr]

One thing i'd add is that for mucking about i the garage, carbide tools are not worth the cost, you cant get the RPM from a bridgeport to reep the benefits of it.

You can if you hack the spindle controller to use field weakening.

3000 RPM before, 12500RPM after! I have to admit it doesn't sound happy at top speed so I rarely run it above 8000. I like carbide & cobalt cutters - particularly on Stainless or duplex. Overall they seem to last a lot longer than HSS though are much more prone to chipping bits off the cutting edge - particularly if you cannot clear the swarf fast enough with some materials.

With CNC, because you can cut interpolated holes (cutter moving in a circle), you only need a small selection of cutter sizes (I only really keep 8, 10, 12mm) which you can use to cut any size hole.

I have a brand new, unused R8 Vertex Autolock chuck which will take metric & imperial cutters from 6 to 16mm. I bought it in error - I only use QC#30. If it would be useful to you - you can have it for free! PM your address and it will magically appear in a few days!

Si

[longlandy]

One thing i'd add is that for mucking about i the garage, carbide tools are not worth the cost, you cant get the RPM from a bridgeport to reep the benefits of it. Carbide doesnt grind as sharp as high speed steel either so high speed steel tools will give better finishes and easier/cheaper regrinds.

Tool storage is important.. If you bounce tools around the floor, throw them into a box full of other tools, they wont be sharp for long.

Carbide is the way forward for running machines without coolant,the nasty foreign steel with hard spots, and repairing/modding stuff the laser cutter got wrong! as hss wont last five minutes on it

[vulcan bomber]

Carbide is the way forward for running machines without coolant,the nasty foreign steel with hard spots, and repairing/modding stuff the laser cutter got wrong! as hss wont last five minutes on it

Run at the right speed with good quality coolant, hss will last a while on all normal metals. We still use it alot at work both on the milling and turning sections. Carbide imho is only really needed in industry, not someones garage unless your trying to machine exotics.

[LandyManLuke]

Thanks all, this thread has been very useful. I think initially, the emphasis on tooling will be low cost, whilst I find my way, then I might look at a few more of the options. Increasing the spindle speed is an option as I'll be running it off a VSD. I'll have to see how far I can take it in to field weakening without it running out of puff.

Now off to send a few PMs

Thanks,

Luke

[LandyManLuke]

Thanks to SiR's generosity, I know have an R8 vertex chuck. On the test fit this evening, I found that either the draw bar is too long, or I am missing a collar from the top of the spindle.

The hex on the end of the draw bar sits down inside the spindle tube, so you can only use a socket on it, not a spanner, is this normal?

Luke

[longlandy]

Thanks to SiR's generosity, I know have an R8 vertex chuck. On the test fit this evening, I found that either the draw bar is too long, or I am missing a collar from the top of the spindle.

The hex on the end of the draw bar sits down inside the spindle tube, so you can only use a socket on it, not a spanner, is this normal?

Luke

Yes that is normal, also some drawbars are extra long with a collar . This is because the thread wears in the hardened tool, so once the first inch is worn out you trim it off and remove the collar to get double the lifespan.