# Buying a Bridgeport



## boneyard51 (Dec 10, 2019)

Ok, my friend , who him and I are building B-Mod dirt track cars says he wants to buy a mill! I say this and that, he’s says he’s buying a “ Bridgeport “!    And since I claim to be the machinist in the bunch..... it’s my job to select the correct machine at a reasonable price! Oh ****!  While I do have a limited background in machining..... I never ran a Bridgeport mill!  What do I need to look for in determining if the mill is in good shape? Which “ head” is the good head? Is there any machines I should stay away from? The main thing is to get a good machine!  ........... the distance second place winner is price! Can I get some help?






Bones


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## ArmyDoc (Dec 10, 2019)

What's your budget?


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## markba633csi (Dec 10, 2019)

Do some research Bones before you commit to buy one- you'll get taken if you just plop down money
The slides, table and feedscrews tend to wear, and the variable speed heads can be a bear to rebuild
What kind of jobs do you want to do with it and to what degree of precision? 
Mark


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## projectnut (Dec 10, 2019)

As mentioned things to look for are leadscrews, table/way wear, knee wear, spindle noise, and smooth operation of the quill.  I would look for a machine with a 1-1/2 HP or larger motor, and a 9" x 42" table.  Tables come in several sizes, I believe from 36" to 49".  Some of the earlier machines are as little as 1/2 HP.  While the do work, the larger HP machines, in my opinion are more desirable.  The 42" table is the most popular size, and gives a good work envelope. 

To check for table/way wear I would loosen the table locks and grab the table at one end.  Then attempt to jiggle it in both the X and Y directions.  There shouldn't be any noticeable movement.  If it has a DRO watch to see if the values on the screen change.  A couple tenths would be acceptable, but not much more.  I would then tighten the locks and attempt to move the table.  If the table moves easily the locks and possibly the ways are worn.

To check the leadscrews in the X, Y, and Z directions move the crank in one direction until you see the table move.  Set the dial at 0 then turn the crank in the opposite direction.  A machine in good condition should have less than .010" registering on the dial before the table begins to move.  They come new from the factory with about .003" play.  Up to .030" could be tolerated for some period of time, but it would indicate the leadscrew or nuts are worn, and will eventually need to be replaced.  Nuts aren't that expensive, but a leadscrew can cost upwards of $300.00 ways.  The table should move smoothly the entire length of travel in the X and Y directions.  Tightness at the ends indicates possibly worn ways or leadscrew.

Run the head through the entire RPM range.  There should be no abnormal noise or vibration at any speed.  Also be sure to move the head between the high and low range.  It should slide easily.  If it doesn't it's a sign of poor lubrication. Also be sure to check the spindle brake.  It should hold the spindle steady when loosening or tightening the drawbar. 

As for the choice of heads I prefer the variable speed.  If you intend to drill and tap a lot it's far easier to change speeds with a variable speed head than having to reposition the belt.  These heads are a bit more difficult to rebuild if needed, but in my opinion the difficulty is far outweighed by the convenience of easily switching speeds.  Even if you do find the head needs to be rebuilt it's a once in a lifetime project for a hobbyist.  My machine was built in 1972, used in a high school for nearly 20 years, put in storage for another 10 and has spent the last 17 years in my shop.  The head is still in good shape.

I would make sure the ram a will move forward and back on the ways, the head can be nodded, and the turret can be swiveled left to right.  The head should also tilt left to right.  Be careful when loosening the lock nuts.  Make sure there is still enough tension to put pressure on the head.  If the worm gear is damaged or disconnected the head could swing down quickly causing damage or injury.

Make sure the quill lock, down feed handwheel, and auto down feed are operational.  Insert a collet in the spindle to determine if the alignment setscrew is present, and if it is damaged.  Many people remove the setscrew, which isn't a big deal.  However if the collet won't fully seat it's possible the setscrew or the drawbar are damaged.

If possible I would also attempt to tram the head in several places on the table.  It should be the same throughout the length of travel.  Different reading would indicate a possible loose gib, bent table, or wear on the table or ways.

One last thing.  Be aware of new paint, and a claim that the machine has been "rebuilt".  Many times a rebuild consists of a wash job and paint.  If the machine was truly rebuilt ask to see the receipts for the parts.  The one time I did buy a "rebuilt" machine (in this case a lathe) the owner was happy to show me the parts list, receipts, and repairs needed.

I'm sure I've forgotten a few things.  Hopefully someone else will chime in with the things, I've missed.


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## FOMOGO (Dec 10, 2019)

Good write up, I believe there are some 10 x 52's out there too. Mike


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## boneyard51 (Dec 10, 2019)

ArmyDoc said:


> What's your budget?


Budget  while it’s not unlimited, we are trying to not spend any more than necessary. I’m thinking in the $3000 range.




 Bones


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## boneyard51 (Dec 10, 2019)

markba633csi said:


> Do some research Bones before you commit to buy one- you'll get taken if you just plop down money
> The slides, table and feedscrews tend to wear, and the variable speed heads can be a bear to rebuild
> What kind of jobs do you want to do with it and to what degree of precision?
> Mark


Well, we are going to use it in dealing with race engines. I think my little Rong Fu or my Clausing 8520 could handle anything we need. But the boss ( money man) says nothing but a Bridgeport will do for the shop. I told him a Millrite MVN was for sale about a 100 miles from here , asking $650..... He said he wants a Bridgeport!
So I guess  a Bridgeport it is. He mainly wants to be able to work on the heads and pistons with the machine.
i am not familiar with the Bridgeport at all, don’t know what it’s tolerances are new or what is acceptable wear. I canmot see needing a bed over the legth of a BBC head. Not sure exactly what that is.
I understand  there are two main “ heads” for a Bridgeport? One is more desirable than the other?
We will not be doing any “ production” with the machine. I also perfer hand operated dials.




Bones


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## boneyard51 (Dec 10, 2019)

projectnut said:


> As mentioned things to look for are leadscrews, table/way wear, knee wear, spindle noise, and smooth operation of the quill.  I would look for a machine with a 1-1/2 HP or larger motor, and a 9" x 42" table.  Tables come in several sizes, I believe from 36" to 49".  Some of the earlier machines are as little as 1/2 HP.  While the do work, the larger HP machines, in my opinion are more desirable.  The 42" table is the most popular size, and gives a good work envelope.
> 
> To check for table/way wear I would loosen the table locks and grab the table at one end.  Then attempt to jiggle it in both the X and Y directions.  There shouldn't be any noticeable movement.  If it has a DRO watch to see if the values on the screen change.  A couple tenths would be acceptable, but not much more.  I would then tighten the locks and attempt to move the table.  If the table moves easily the locks and possibly the ways are worn.
> 
> ...


Projectnut, thank you fir taking the time to type that out! It was very informative and if I check all of that I should get a machine that will work for us. Is the differences in the heads,only variable speed and one that you have to change belts? 
Is that the “ J” head and I think “ m”? head??
Also tell me a little more about that “set screw” ....is that  actually a set screw or a thing you push in to lock the spindle to tighten the drawbar? Again thanks for your time and knowledge !





Bones


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## projectnut (Dec 10, 2019)

Over the years Bridgeport has made a number of different style mills.  The most common are the Series I J head  (step pulleys for head speed change) and the J2J head which achieves the variable speed by using a crank on the front of the head to change the width of variable sheaves in the head.  These are the most popular models with both having the head attached to a ram with V ways.  They are generally powered by 1 hp to 2 hp motors, and use J8 collets.  The original collets go up to 3/4", but many aftermarket brands will go to 1".  Personally I would not recommend using anything over 7/8"

The older model M head machines are usually 3/4 HP, have the head attached  to a round ram, and use a #2 Morse taper style collet that only goes up to 1/2"  They are less desirable because of the lower HP, the fact that the round ram makes the head harder to adjust, and the collets only hold smaller tooling.

Bridgeport also made Series II machines.  They are much larger than the series I machines, and less popular outside the professional production shops.  Both the series I and series II machines could be purchased in CNC versions.

Personally for the type of work you are proposing I would recommend a series I machine.  If you plan to use it for plaining heads a power feed on the X drive might be something to consider.  They are available as addons from many manufacturers, and usually run between $200.00 and $400.00 depending on the quality.  If you decide to go with one be sure to get one with 150 in/lb. output.  Some less expensive ones only have a 135 in/lb. output.  They will likely not last long.

As for the setscrew in the spindle it's a "permanent" feature that is used to align the collet.  The plug shaped end just sticks slightly into the spindle bore.  The setscrew itself does not have to be manipulated.  If it is present the collet has to be rotated to align the slot with the setscrew.  They can be removed as mentioned earlier.  Many production shops remove them to make installing a collet less time consuming.  From time to time they also get removed or replaced because a collet has spun in the spindle and damaged it.  The one in my machine was slightly dinged up from use in the high school.  Because of a slight burr it made installing and removing collets a bit more difficult.  I replaced it when I first got the machine, and it's been fine since.  

The real experts on Bridgeport machines are at H&W Machine Repair & Rebuilding.  You might want to give them a call.  They not only rebuild and repair machines, they also offer any parts you can think of, and sell used and reconditioned machines.  I've done business with them over the years.  They are very helpful and eager to share their knowledge.






						Homepage
					

H&W Machine Repair and Rebuilding Machine Parts & Accessories Services Technical Support Machine Sales Specializing in Bridgeport Milling Machine Parts and Repairs Servicing the metal working industry since 1982. Since 1982 H&W Machine Repair & Rebuilding has been providing machinery sales...




					www.machinerypartsdepot.com


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## boneyard51 (Dec 10, 2019)

Ok , got it! I guess the set screw is not a real big thing, as it can be replaced easily? If the threads are in good shape?
with this info, I should be able to determine the condition of the machine. No more than we are going to do with it, an old semi wore out  machine would probably do us, but I’m going to try to get the best machine I can find.
I will give H&W a call if we get one spotted!
Did you mean R-8 collets?  And I guess you can “ tilt” the J heads, even though
they are on ve ways?

Thanks a million! I feel I kinda know a little about the Bridgeport , now!




Bones


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## markba633csi (Dec 10, 2019)

Tilt and nod are different things- nod is like when you nod your head and tilt would be like leaning your head to the left or right. 
Then there's swivel which is like turning your head left or right keeping your eyes parallel with the horizon
Also, I believe the shortest Bridgie table is 32", I have seen a few on Ebay that short. 
The longer tables can actually be bent if you can believe that, but not from having heavy things put on them. It happens from overtightening the t-slot bolts holding the vise over a period of time- it apparently warps the table.  I have heard it can be corrected by peening the underside of the table, not an easy job though.
The variable speed heads are fine if they are in good shape when you buy it- if you find one, spend some time running it a different speeds and listen for bad noises and vibration.
Bridgeport isn't the only game in town, it's just the best known.  Other good mills are Cincinnati, Index, Van Norman, and Gorton


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## projectnut (Dec 10, 2019)

Sorry I had J on the brain after thinking of the Jacobs collets.  The collets for the J head and the J2J head machines are indeed R-8.  The heads on these machines can be swiveled on the turret left to right.  It can be "nodded"

Here's a link to a video showing a Bridgeport series I head being rotated in the Y direction.  I referred to it as "nodding"






Here's a short video showing the head being "rotated in the X direction.  I referred to it as "tilt in my first post.






Here's a short video on rotating the head on the turret.  This isn't a Bridgeport, but it works the same.  This video shows only loosening 2 bolts.  Bridgeports have 2 more on the opposite side of the ram.






Finally here's a link to the manual for a Bridgeport Series I machine.



			https://www.hardinge.com/wp-content/uploads/KneeMill-Parts-Older.pdf


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## brave_ulysses (Dec 10, 2019)

well, iirc some of the hurcos had bridgeport heads on them :0

in any case the price is right...maybe
https://dallas.craigslist.org/ftw/hvo/d/alvarado-hurco-cnc-kmb-1/7028443159.html

looks like about a 4.5 hour drive. good luck with whatever you end up with


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## boneyard51 (Dec 10, 2019)

markba633csi said:


> Tilt and nod are different things- nod is like when you nod your head and tilt would be like leaning your head to the left or right.
> Then there's swivel which is like turning your head left or right keeping your eyes parallel with the horizon
> Also, I believe the shortest Bridgie table is 32", I have seen a few on Ebay that short.
> The longer tables can actually be bent if you can believe that, but not from having heavy things put on them. It happens from overtightening the t-slot bolts holding the vise over a period of time- it apparently warps the table.  I have heard it can be corrected by peening the underside of the table, not an easy job though.
> ...


Yeah, I’ve got a Rong Fu, aClausing 8520 and an index mill, but my friend is dead set on a Bridgeport..... his money, his way! But..... that’s good...... I get to play with a new machine.  Thanks,I will get on that  mill motor tomorrow.....I hope! Thanks guys!




Bones


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## projectnut (Dec 11, 2019)

I'm not familiar with the Rong Fu and the Clausing, but I do know Index machines are good machines.  The only downsides to most of the similar built or clone Bridgeports is the availabiliry of parts.  Index is still in business under the Wells Index name, however there aren't many dealers willing to supply parts for older machines.  There simply isn't enough volume for them to make it a priority.  With low volume parts sales you can imagine what that does to the cost of individual parts.
The other downside is that the clones/similar machines are just enough different from Bridgeports (to avoid infringing on patents) that some parts interchange, and others don't.  In many cases the only suppliers of clone parts are their manufacturers.  Because the Bridgeport name is widely recognized many people think their used machines must be more valuable.  The initial asking prices are often times unreasonable.  

If you're patient I'm sure you can find a quality machine for a reasonable price.  There are currently several offerings in the Wisconsin area ranging from $2,800.00 to $8,700.00.  The only visible differences between the 2 is that the more expensive one has a Bijur oiler, DRO, and power feed on the X axis.  All of those accessories can be purchased new for less than $1,500.00.  This machine is obviously not being sold by the original owner in that the text in the add states "This machine appears to be in good condition and seems to have been taken care of."


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## mmcmdl (Dec 11, 2019)

Don't rule out a nice Lagun FTV1 2 or even a 3 if you come across one or even an Enco mill . The variable speed heads are handy but the Encos have 2 speed motors which can get you in the ballpark usually . I have BPs , Laguns , Encos and Alliances in at work and all are good machines , but they are maintained nicely . The name Bridgeport is synonomous with a knee type mill , but there are plenty others out there .


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## boneyard51 (Dec 11, 2019)

We are just starting this journey and my friend, who will be purchasing this machine, says “ Bridgeport” !  For what he is wanting to do any one of my three machines would do the job! But none of my machines are running now! I have the worst luck with mills. The very first I actually  traded for, was an Index, older machine, 3 phase. I have not completed my three phase conversion set up... so no run! Then I buy a Clausing 8520 mill and a Clausing 12 inch lathe and a truck load of tooling, for  $500. The owner decides to pull the mill out of the garage with a tractor and tips  it over, bending the lead screw and handle, dial etc. So, no run! Then while I was in Pennsylvania I run across and ad for a Rong Fu mill for $400,  I buy it for $200, go to pick it up... no belts, screws missing, motor wires  not hooked up, no tooling. I buy it anyway. Haul it to Oklahoma, in my mini-van. Put it in my shop at my house, still no run!    So..... now my friend wants a Bridgeport..... but he will only buy a nice running machine!  I may get to make some chips ..soon! I hope!  Lol


Now, I’ve got my eye on a Millrite MVN.... when the price gets right! I’ll never learn!


Bones


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## Kroll (Jan 2, 2020)

Well I'm month late,but I can understand your boss wanting a BP.For me his reason is just about all parts are still available which is a plus.So I would think that main concern would be the ways.Which where the saddle sets would be a focal point,I would move it just about all the way end towards the column then maybe see if you can feel the ways where most of the wear will be.The the next area would be where the table sets on saddle, maybe focus on that also.I think that if it has a one shot oiler see if it looks like its been used and if all the ways have film of oil on it then maybe mill was taken care of. But buying used its always a roll of the dice,and finding a used BP that only a hobbyist has ever use would be like winning Lotto.


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## hwelecrepair (Mar 16, 2020)

projectnut said:


> One last thing.  Be aware of new paint, and a claim that the machine has been "rebuilt".  Many times a rebuild consists of a wash job and paint.  If the machine was truly rebuilt ask to see the receipts for the parts.  The one time I did buy a "rebuilt" machine (in this case a lathe) the owner was happy to show me the parts list, receipts, and repairs needed.



Killer advice.  My only addition to this is the addition of fresh flaking to show that there is no way wear on the knee.  

Jon
H&W Machine Repair


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