Learning to use a Bridgeport mill

Hey All,

Now I am the proud owner of a Bridgeport I need to think about how i learn to use it!

My first question is where can i find a manual for it or any guides?

My second question, is there anybody in the southwest (Bristol) that has experience with them and would be willing to offer a few face to face lessons on it?

If a type 1 Bridgeport you could download a manual here or here.

Thor

Edited By Thor 🇳🇴 on 13/05/2023 17:04:04

Thank you Thor, that is a great starting place!

The whimsical and under-rated Stuart de Haro has a Bridgeport, and has posted numerous videos that may help you get the most out of your machine.

A bit late for you now, perhaps, but he's even done one on buying a [Bridgeport] mill.

Edited By Bill Phinn on 13/05/2023 17:29:13

Hello 'Rooos'

I worked Bridgeports for several years and had two factory fresh ones at one place where I was machine shop supervisor. I don't recall ever seeing a manual! That's not to say there wasn't such but I certainly can't remember one.

Using one is much like any mill - you just need to acquire the skill and that takes time but the one thing to ensure is that the head is perfectly trammed in both x and y directions at all times other wise any positional work using the quill will be affected - do not just rely on the alignment peg to square things up

The other is to keep in mind is that it's a light mill on the scheme of things and not really up to big heavy cuts or feeds. Apart from that a Bridgeport is a brilliant, extremely versatile, machine tool in my mind.

Good luck with your journey - you have many happy hours ahead of you

Best - Tug

Try Frank E Marlow's Machine Shop Essentials. Chapter 8 covers milling, and is Bridgeport centric.

The book is American, fairly modern, well-written, with lots of pictures!

My workshop is too small for a Bridgeport so I'm used to a much less rigid Chinese machine. All mills work in much the same way, allowing work clamped to a table to be moved X,Y relative to a cutter. In some machines Z movement is provided by a quill moving the tool, a more rigid solution is the lift the whole table.

Bridgeports are desirable because they're moderately rigid and come with lots of reliable features - versatile, general purpose and aimed at small professional workshops. Not much to criticise. Biggest risk with them, I think, is a tendency for owners to assume sheer size, weight and power mean they can maintain accuracy whilst taking seriously heavy cuts. They're good, but not that good.

Not the Bridgeport's fault, but perhaps they encourage overconfidence. It's more obvious that smaller mills have limitations, but all machines have a sweet spot, and part of the learning process is finding it. Don't panic, it's fairly broad.

Two common beginner mistakes are either going in too hard or pussyfooting. I was a pussyfooter, until this forum put me right (thanks Andrew). The problem with taking very light cuts is it quickly blunts the cutter for very little in return. Results worsen until the learner evenetually realises the cutter is blunt, and then - because he only tool light cuts - he's convinced the cutter must be cheap rubbish. Possibly it was, but beware; light cuts quickly destroy sharp edges on good tools.

What's needed is a cut of decent depth coupled with about the right feed-rate, with a sharp tool spinning at about the right RPM. Getting the combination right optimises finish, metal removal rate and accuracy. Taking light cuts with a blunt cutter is bad news, and so is a vicious assault that strains the motor and drive train, flexes the machine's frame, bends the cutter, and overstresses the sharp edge. I start with rule of thumb settings:

• rpm = 10000 / cutter diameter in millimetres. This is about right for HSS and mild-steel. Apply a multiplier for the material, for example half for cast-iron, x5 for Aluminium, x2 for Brass. If the cutter is carbide, multiply the above again by 2 or more.
• depth of cut 5 to 20% of cutter diameter, I go for a little over 10%, or an eighth because the mental arithmetic is easy
• feed rate by ear and eye. The finish should be reasonable, and I like to hear the motor and drive train sound loaded to about 20% short of complaining! i.e not straining or idling.

May be necessary to experiment with all three, but usually tweaking the feed rate is enough.

Practice, and avoid unknown scrap. Buy known metal where the spec has words like 'free cutting', or 'good machinability'. Many alloys are not easy to machine, and some are impossible! Pussyfooting with a lump of work-hardening stainless steel is heart-breaking.

Dave

The late Sir John wold have been wearing a black armband for your purchase as opposed to buying a 'Beaver', BUT, having being brought up on a Bridgy, only comment I can give is it's a milling machine, NOT a cleaver. Same comments are forgotten of Lathes.

Regards Ian.

Nothing wrong with Bridgeport's, I made my living on them for many years, super versatile machine, I wish I had one in my garage!.

Tony

Plus 1 for the comment, I to made my living using one and now have one on my garage. To the new operator. Listen to the machine, it will tell you if it is unhappy.

There are a huge number of accessories made for Bridgeports and all of them have many features not found on common mills. Having a good book to find out about them is a great idea.

Hi Tony, Not sure what you mean by wearing a black armband as opposed to buying a beaver?

Everybody on this forum is amazing. I thank you all for your engagement.

I am under no illusions that I can be taking .5" passes through hardened steel on it My main need was size and boy, is it big enough!!!

I am most certainly more with Dave in that I'm more at risk of damaging through pussyfooting!! I really appreciate you breaking down your formula for taking cuts, I will take that with me for life!

Finally, Mr old mart, I have a library's worth of reading material for machining but probably not anything that discusses Bridgeport accessories, do you have any suggestions on that front?

Sorry, my only Bridgeport experience is from seeing my old firms toolmakers using all sorts of fancy extras on their pair of machines for one offs. I do know that there are lots of controls that rarely get used that you need to be aware of.

A picture would help before commenting, as there are variations on table size. power feed and especially the type of vertical head.

Andrew

I did manage to find this Mr Lucas video...

I found another i thought to share, This one is an hour long so relatively comprehensive by comparison to other videos....