Your opinin please - evaluating a used Bridgeport to purchase

[jkujawa]

Hello,

I am looking at a used Bridgeport machine for my shop. We do light prototyping, mostly in aluminum, and though I have used a mill it has been some years so I am definitely a novice.

The machine I am currently looking at is priced around $4k, and has power knee and x, Sony DRO, pneumatic drawbar, Bijur oiler, and comes with collets and a vice. It has been in service in a place that does repairs on airplane components (they are FAA certified). The shop is very clean, large, and well equipped. In general all their equipment is current and very clean. This particular machine is being sold because they don't have the work to keep it busy and they are consolidating space. He admitted that this is the least 'tight' of the machines, but it only recently came out of service.

The owner of the shop seemed knowledgeable and honest. He told me what he knew about the machine, and what he didn't. He had no problems with me talking to the machinists about it. I am going back tomorrow or monday to fire it up and check the runout (I knew in advance I couldn't run it today because there was no power where it is. One of his crew offered to shuffle the machines to position it to run, but I didn't want to disrupt the productivity as my visit was unscheduled).

I have two questions:
1) The flaking on the Y ways is just barely visible, but the travel is smooth and consistent. In the last 3 photos below you can just barely see the pattern (it is a little more evident in person). What do you think about the wear? I am, as I said, completely inexperienced in this field.

2) The unit overall seems to be in good condition, and I think it will easily meet my needs (I'd like to be able to machine parts, mostly aluminum, with .001-.003 accuracy). What do you think a machine like this is worth?

Thanks very much!



They are replacing the switch. The part is actually in the photo, in that brown box.


A few shots of the ways - the brown stuff is NOT rust. It is kind of a waxy oil film.

[snakebit95]

Well, the first thing I noticed when I looked at the photos is that the head is a different color than the base; which indicates it was replaced at some time. You might ask the question. I would also run the head through various speeds, listening for noises. Perhaps start in low-gear and step through a couple speeds, and then run a few speeds in high-gear.
Your photos of the ways indicate some significant wear. In my opinion, $4K is a bit high. But then again, most of the machines I see in good shape that sell for $2.5K-$3.5K do not include digital readout or power drawbar; so those items do add-up.
You may want to check the backlash in each axis to get a feel for the wear on the screws / nuts.
Finally, if you decide you want the machine.......I would ask them if they have a vise, collets or clamp-set they would throw-in on the deal too. Usually shops have more than they need, and are more than willing to throw in a few things to help a hobbyist. Hope this helps!!

[jkujawa]

Thanks very much for the response. Yes, the guy said he'd include a set of collets and a vice, and the machine also has a Bijur oiler. I did ask about the head and he said he was not sure of the history of the machine (they had 6 or 8 almost identical machines in a row, so it is believable that he doesn't remember). I am going back tomorrow with an acquaintance who is much more knowledgeable than I (incidentally, he had the exact same comments as you when I sent him the photos!)

One of the challenges where I am (S. Florida) is that there are relatively few machines down here, as there are not many 'industrial' areas. As a result, there don't seem to be as many used machines floating around. To get a machine from, say, Michigan is about $1100 + crating, so unfortunately location comes into play.

I'll let you know what a second inspection turns up. Any other thoughts, comments, recommendations?

Also, I have the serial numbers from the head and body. Is there any way to decipher these (eg, determine year, model, etc?) Thanks again!!
John

[NC Cams]

Check the fit of the ways at the extreme limits of travel.

If the table motion gets real tight as you approach the end limits of travel, they could have adjusted the slop out of the more heavily worn center travel area to "make do". THis isn't all bad just a PITA if you need to use the extreme limits of table travel.

The lean on the table/wiggle it around while you have an idicator in the quill test works here.

Look for table dings. A well used machine WITHOUT table dings suggests that the thing was well cared for or at least not horribly abused.

Run the head at min/max speeds in all gear change ranges. Run it with table as low as possible and with quill fully extended - severly worn or bent spline drive will drop out at full extension (high $ to repair).

$4k seems a bit high unless machine is in prime condition - even so......

I have an Excello in comparable shape WITH a DRO and ALL ORIGINAL with full documentation that is for sale now and I'm only asking $2900. Too bad I'm in Michighan. We'd gladly load it on your truck and cover part of the shipping for a $4000 selling price.

[NOCARRIER]

Did you buy this machine? I understand where you are coming from as I am also in South FLorida and the pickings are really slim. I ended up buying my bridgeport in South Carolina. I paid $6000.00 for it but the ways had tons of flaking and the table didn't have a single nick in it.

I knew the machine was well taken care of just by looking at it. I didn't mind spending a few extra bucks to get a cream puff.

[handlewanker]

Power knee and X with digital readout, oiler, air drawbar a vice thrown in and collets! The only thing I'd be worried about is if someone else found out about it and got there before I did, and paid the money.
If this item had been at auction then you would have to keep your fingers crossed as well. 4K, how much did you think you would get it for?
Ian.

[jkujawa]

Originally Posted by handlewanker Power knee and X with digital readout, oiler, air drawbar a vice thrown in and collets! The only thing I'd be worried about is if someone else found out about it and got there before I did, and paid the money. If this item had been at auction then you would have to keep your fingers crossed as well. 4K, how much did you think you would get it for? Ian.

Thanks for all the replies!!

Ian - I am having a hard time figuring out 'reasonable' values, so I really don't know what I should expect to pay for it. I certainly don't expect to find a give-away, but I don't want to get ripped off either. As you can see from the responses above, even on this board of experienced people there is a wide difference of opinion about what these items are worth.

NOCARRIER - I have not bought it yet. We had a trade show last week (IBEX, in Miami) so we were pretty wrapped up in that. I am going back today to run it, and taking along a friend who is more knowledgeable than I. If you don't mind I will send you an email with some additional questions. Since you are local and have gone through this I would appreciate any help you might be able to offer (eg, who I can contact to refinish the ways if in fact that is all the machine needs to be 'pristine')

Thanks again!!
John

[NOCARRIER]

Im not sure however, if you are buying a machine with the intent of re-conditioning it, I'm not sure this is the machine you want. It seems like you need a super precise piece of equipment. Remember downtime is expensive. Personally I'd rather make a road trip for the right machine. As for the complexity of finishing the ways, I still havent found anyone in the state of Florida that does it. Keep in mind that the chrome plating on a chromed bridgeport needs to be removed, re-chromed and then scraped to fit. It is not cheap by any means.

My opinion is as follows: While tooling may be expensive I have the ability to repair, make, install modify, scavenge on e-bay, most of my tooling needs. As for repairing the machine I'm pretty much sure I can get by with most of the mechanical aspects of thing like the screws, head etc. When it comes to the ways of the machine (essentially the "heart and soul") , I have no experience nor the will to try practicing on such a rare (being the slim picking of our area) commodity in my shop. The ways are delicate, precise, rare, and actually quite demnding. I find constantly cleanining thinking about those ever so minute particles trapped in the way wipers eating my machine away.

Lots of tooling is great, but a machine that can't properly use the tooling that comes with it does not bring good karma.

[snakebit95]

Hey John,
You will always find a wide variety of opinions on this forum because everybody has different intentions for these machines. If I owned a production shop and relied on the machine to produce income daily, I would definitely be looking for a top-notch accurate machine that I did not have to repair all of the time. For the typical garage / small shop hobbyist, this type machine takes the cake!! I think it depends on what you plan to do with the machine, and what type of parts you expect to make on it (based on level of precision). NOCARRIER makes a lot of good points. The ways are probably the most critical feature of the machine that could cost a lot of money to refurbish. Most other parts can be replaced without too much trouble. Tell us a little about what type of work you plan to do on this machine. Will you be using it as an over-kill drill-press, or will you be machining intricate parts? The decision is pretty simple if the plan is to machine highly precise parts on it.

[One of Many]

I'd guess this to be a late 80's to mid 90's mill. Either a lot of hours, or a combination of the results of the material cut on it, bad way wipers and/or improper lubrication.

The wear looks consistant, but should be investigated with an indicator. By the evidence of swirl patterns, someone has done a masking of the real wear with an abrasive disk of some type. That much wear would break through the chrome. Rubbing with copper sulfate solution should show what is and isn't still chromed.

You could set the table in the center of the y axis and tram the head there. A 12-15" piece of ground bar atop the table parallel to the y axis could be indicated atop the bar while then moving the y axis to disclose any rise at the extremes or actual wear from center to extremes. You could also move the ram back and double check the tram at each extreme. This tells you that the table does pitch toward the shallower wear areas.

I'd also do something similar as NC Cams suggests and place the x axis at its extremes then push and pull while the y is in different locations along is travel. The saddle may shift quite a bit in the center, but tighten up at the extremes where the wear is minimal. With all that weight overhang of the table, you can again check the tram to see excessive table tilts further. A feeler gage in the y axis lifting side is another indication of severe wear on the dovetail.

The original Bridgeport specs don't even claim any better than .001. Much of that will be operator experience in getting the machine to do as expected during setup, regardless of its condition. What they did claim, as I recall was a 9" square patch on the table over the saddle. Point to point is a small part of these variables. Retaining things square and parallel once the table is moved to another position can be where a lot of precision is lost.

4 grand is about average in the Northwest for a basic manual mill. The tooling and bonuses of the DRO and draw bar do make for a decent machine, but if it is a pain to use due to its wear, I'd consider making them an offer that makes you comfortable to live with its condition. Even if you found another mill in better condition and transfered all the goods over, you may still be ahead selling the iron on its own.

The asking price and fetching price can be quite a difference if they really want it gone.

DC

[jkujawa]

Thanks yet again for all the great comments.

Whichever machine I get will see very light use - probably less than 20 hours per month. Right now I do not have the need for an extremely precise machine. I will still send out any CNC jobs or items that I need more than 2 or 3 of.

One of Many - Good eye! Yes, you are absolutely right regarding the crude repair of the ways. The table still rides true and tight though so while it is not ready to go back onto a production line, I think it will allow me to accurately crank out a handful of prototype parts a month in 6061.

I did find a few companies who will refinish the ways. Unfortunately as NOCARRIER indicated none are here in FL. Nonetheless, my thought is that if I use this unit for a year and find it is not quite up to snuff I could pull off the knee, ship it out, have it completely refinish with stripping and re-chroming, rescraping and flaking, regrinding and squaring the table, etc for about $3k. I did make an offer on the machine so the net result is if they accept it I'll have a machine I can get started on, and if I have to do all the repairs I'll end up with a machine with a load of years of use still in it (basically with nearly-like-new head/ways/table), and some nice options for a reasonable price.

I'll keep you posted. Thanks again!!

[Willbird]

I didnt see it mentioned, so I'll say it, make sure all of the quill feed positions work properly :-). Also alternately tighten and loosen the 4 bolts going in from the front of the head, I have seen some with broken casting in there from over tightening. I would also make sure both worms work properly (the ones that pivot the head right to left and front to back), and check the column studs too, go over the whole machine if you can and tighten and loosen each of those bolts/nuts one at a time. Check the rack that moves the head dovetail in and out

I see in the picture this is not the case, but them weirdest dang thing I ever ran into is that the worm that pivots the head right to left is an OPTION, I did not know that, one place I worked we had a bport without it....thats the only one like that I ever ran into in being around them for 30 years :-).



Bill