Tips on what to test when buying a used machine to recondition or use.

Richard King · Feb 21, 2018

In another thread the OP asked about Way Wipers and it got me thinking of a simple test when looking for a well maintained or poor maintained machine. Next time you go and look at one or even one in your shop. Take a set of feeler gages with. Wipe off the ways in front of. The wiper a see if you can slide the gage under the wiper.

I just inspected (class inspection) a Bridgeport and we could slide in .004" under the front of the knee wiper. It. W as obvious from looking at the hatched ways it would slide in. But I wanted to show the students. This can be done on lathes and mills.

Richard King · Feb 21, 2018

Sitting in a traffic jam. Have some time. Another test on bigger machines that have an electrical cabinet, is to open it and not only look in there for jumpers (lose wires with clips jumping from device to device, the inside looks like a bird's nest or neat. Take the sniff test. Stick your head in there and sniff it. If it spells like fire have an electrian take a look.

A real simple test on a lathe other then the ways. Look at the rack under the bed. It will not be worn up near the chuck. But if it's worn about 2 feet back from there the rack teeth will be sharp or wider pitch.

Tyrone Shoelaces · Feb 22, 2018

On a lathe drain the oil from the apron, on a milling machine drain the oil from the knee. If clean oil comes out great. If coolant or a coolant and oil sort of mix comes out be prepared to reconsider your purchase. Spare gears etc for these areas will not be cheap or easily obtainable.

On a general theme does the coolant pump work, does the work light work, are all the original plastic knobs/switches still existing ? Has the machine got it's full compliment of vee belts ? You can manage without all these things but their condition is indicative of how the machine has been treated by it's previous owner.

Another thing that I was wary of. Has the machine been recently re-painted ? I always preferred machines in their original paintwork even if it was a bit tired.

More to follow when I've woken up properly.

Regards Tyrone.

Peter from Holland · Feb 22, 2018

From a picture ( I know its hard but I buy from a picture on a general base )
look at the paint and try to determon if its original paint or that the machine is repainted
If its original paint look at the wear of the paint Where and how much is it worn off
Look through the dirt Thats easy to clean

To get a indication of wear on the bedways Put a indicator on the ways and carriage and lift it at different places
The difference in those readings is a indication of wear You measure againts the underside of the ways which sees little wear in general
Also look for visable wear on the backside of the V Most people look only at the front The backside is worse in general

Peter

Richard King · Feb 22, 2018

Also take a battery powered light...they call it a torch in the UK and we call them a flashlight here. On lathes Use it to look in the spindle holes. Pull the belt covers a bit like looking under the hood of a car. Test run it. I used to get a kick out of customers who had bought a used machine "as-is" and never ran it thru all the feeds and speeds to test it. They would be calling me to fix it. I said the last time you bought a car, Did you take it for a test drive?

Tyrone Shoelaces · Feb 23, 2018

One obvious thing is the condition of the sight glasses. Do they have oil in them ? Are they clean or are they in such a state you can't actually tell if there's oil in there or not ?

Having said that a decent sight glass isn't always a good guide. I went to a " really noisy " " Auto-Ward " N.C.capstan lathe years ago. They'd modified the old manual " Ward " design by fitting a fancy fascia onto the old headstock casting and joined the new sight glass to the old one with a short length of small plastic pipe.

When I got it all apart it was obvious the plastic pipe had blocked up under the fascia and although the sight glass was showing the correct oil level there was absolutely NO oil in the headstock, just red dust. Obviously everything in the headstock was ruined !

Regards Tyrone.

RC99 · Feb 23, 2018

For me personally, what I would put up with depends on the rarity of the machine. An overview of general condition can tell a lot, but I am not going to expect a used machine to be perfect, unless say it was ex-government or bought with government money through a grant/subsidy,(thus never had to pay for itself).

Do all the controls work? Backlash of screws. Lube systems working. If say for example a lathe bed is hardened and it shows wear, you can be sure as eggs the mating saddle it worn a hell of a lot. Feel the spindle and how it sounds. I feel I can get a pretty good idea just by looking and feeling, but if it is something rare and I want it, I would put up with more then if it is just a general purpose machine of a dime a dozen.

One way to get some idea of lathe bed wear is use the saddle lock say six inches from the headstock then see how far you can move the saddle before it locks up.

How "loose" is the tailstock barrel. Stick a finger or something else like a torch in the tailstock taper and look/feel for damage.

With constrained ways like cross slides, is it tight at the extremes of travel and rattling in the middle.

I have no idea how to check CNC machines.

bebop · Feb 23, 2018

I've found it informative to put a mag base on a slide you wish to check then put the tip of an indicator on something solid that's not moving ......I'm not really checking the
" movement" of the slide ... I'm just going to load the screw from one direction then the other just to see if it shifts / moves in a way that your not expecting it should, not a hard number kind of check but will give you an indication of the wear in the ways/ saddle.
Cheers Don

Richard King · Feb 24, 2018

bebop said:
I've found it informative to put a mag base on a slide you wish to check then put the tip of an indicator on something solid that's not moving ......I'm not really checking the
" movement" of the slide ... I'm just going to load the screw from one direction then the other just to see if it shifts / moves in a way that your not expecting it should, not a hard number kind of check but will give you an indication of the wear in the ways/ saddle.
Cheers Don

DON...longtime....glad to see your still kicking and scraping... you pulled scraped those Sips?

AlexO · Feb 25, 2018

The most important thing to inspect on a used machine is the spindle / spindle bearings and gearbox issues. For a lot of used machines spindles / bearings are not available anymore OR have never been available - there are NO spindle bearings for some MAHOs. Same for some lathes. The second most important thing is the health of the gearboxes. Broken teeth or worn spline shafts can not be fixed short of MAJOR expense.
By comparison, the ways of a machine can be (almost always)fixed and often, better than new. However, fixing the ways beyond a very minor touch up involves relocating screws, shafts, gearboxes ( !!! ) etc. Sometimes, this might not be that easy or even possible. This is a subject almost never discussed here in detail.

pressbrake1 · Feb 25, 2018

I first look at the job its been doing. The biggest lathe killers are hydraulic shops.
Chrome bar dust and cast iron from the glands both of which destroy the ways quickly and no hydraulic shop would sell a good lathe.

I check lube packs have oil and work or the plungers do something with built in lube pumps.

Noise and operation of all functions.

All the above a novice can do

Tyrone Shoelaces · Feb 25, 2018

Yeah, a machine that's been used on cast iron for most of it's life will be showing plenty of wear and tear on the ways. Beware of the machines with covered ways if they've done a lot of cast iron.

I nearly got bitten with a " Ward 7 " that way. The machine looked and felt in good nick but when I pulled the way covers back there were fire ups on both ways.

Regards Tyrone.

Richard King · Feb 25, 2018

OT a litte,

Years ago had to have been 30 I guess a customer called me to come out and repair a hydraulic pump on a Heald ID grinder. As I walked into the bigger shop I could hear it. It was a Vickers vane pump and it is very common when the pump is loud it is sucking air. It's a high pitched whine. The only place it can suck air is on the suction side of the pump or around the motor shaft where there is a seal or back plate seal. An old trick my Dad showed me was to squirt oil on the shaft as it enters the pump and the pipes in the suction side as it goes into the oil holding tank. You listen for the noise to change pitch. I did that and no change, Then I said to the maintenance man who was standing there.

Have you checked the oil level? He said he had just added more oil before I came and it was full. Hmmmmm...sounded good, but I had him remove the cover on top of the tank to have a look for myself. They shut off the machine, pulled the cover and it looked more like milk then light brown hydraulic oil. I said that air in the oil, Then I rolled up my sleeve and reached in the goo....As I felt for the oil strainer in the bottom of the tank I felt a layer of thick goo and when my hand reached the strainer (some call it a oil filter) which was around 3" diameter and 10" long and it screws onto a pipe that leads to the suction side of the pump.

It was covered with a thick layer of goo and that was the problem the pump was cavitating. I said to the maintenance man when is the last time you changed the oil? He gave me this dumb look and said he had never changed the oil, just added it when it was low. I laughed and said "try that with your car engine and see how long it lasts. Moral to the story is change the oil in your machines depending on how often you use them.

This also is so important to clean and change the way oil pump which on many of the Knee Mill is a BiJur style one shot pump and there is a strainer felt and screens on the suction side of the pump. :-) Rich

Richard King · Feb 25, 2018

pressbrake1 said:
I first look at the job its been doing. The biggest lathe killers are hydraulic shops.
Chrome bar dust and cast iron from the glands both of which destroy the ways quickly and no hydraulic shop would sell a good lathe.

I check lube packs have oil and work or the plungers do something with built in lube pumps.

Noise and operation of all functions.

All the above a novice can do

I remember when I was an apprentice 50+ years ago, my Dad got a job rebuilding a big K&T vertical mill inside a black smith metal fabricators shop that made steel stair cases, rails, steel fences and the like. Over on one side of the shop a guy had a shaft in a lathe and was welding on the shaft as it slowly turned. The shop owner walked by and my dad said to him, the spindle bearings in that lathe are shot. The guy said how can you tell that from over here? He said look where he has his ground wire attached. It was on a leveling screw on the headstock so the current was going thru the casting and up through the spindle. So if your looking at a lathe to buy and see welders close to the lathe or you see weld splatter on the ways, walk out of that shop as fast as you can.

pressbrake1 · Feb 25, 2018

Heald borer hydraulics used to be my nemisis! The actuall boring heads(red heads) were beautiful things

Richard King · Feb 25, 2018

That's where I first saw Mobil Red #28 grease. :-)

bebop · Feb 25, 2018

Hey Rich &#55357;&#56846; yup still “scrapen by” ya I did the finish passes pull scraping .... roughed in with my Biax &#55357;&#56847; I don’t want to work that hard.

Cheers

dian · Feb 28, 2018

Richard King said:
OT a litte,

Years ago had to have been 30 I guess a customer called me to come out and repair a hydraulic pump on a Heald ID grinder. As I walked into the bigger shop I could hear it. It was a Vickers vane pump and it is very common when the pump is loud it is sucking air. It's a high pitched whine. The only place it can suck air is on the suction side of the pump or around the motor shaft where there is a seal or back plate seal. An old trick my Dad showed me was to squirt oil on the shaft as it enters the pump and the pipes in the suction side as it goes into the oil holding tank. You listen for the noise to change pitch. I did that and no change, Then I said to the maintenance man who was standing there.

Have you checked the oil level? He said he had just added more oil before I came and it was full. Hmmmmm...sounded good, but I had him remove the cover on top of the tank to have a look for myself. They shut off the machine, pulled the cover and it looked more like milk then light brown hydraulic oil. I said that air in the oil, Then I rolled up my sleeve and reached in the goo....As I felt for the oil strainer in the bottom of the tank I felt a layer of thick goo and when my hand reached the strainer (some call it a oil filter) which was around 3" diameter and 10" long and it screws onto a pipe that leads to the suction side of the pump.

It was covered with a thick layer of goo and that was the problem the pump was cavitating. I said to the maintenance man when is the last time you changed the oil? He gave me this dumb look and said he had never changed the oil, just added it when it was low. I laughed and said "try that with your car engine and see how long it lasts. Moral to the story is change the oil in your machines depending on how often you use them.

This also is so important to clean and change the way oil pump which on many of the Knee Mill is a BiJur style one shot pump and there is a strainer felt and screens on the suction side of the pump. :-) Rich

weirdly enough air was entering the system on the pressure side on my grinder. i wouldnt have thought this possible, but its a fact.

Richard King · Feb 28, 2018

I was thinking once I was asked to go check out a machine a Used Machinery Dealer told a customer they had completely dismantled a machine and rebuilt it. I drove over to the dealers shop and he told me where the machine was at inside the plant and after he got off the phone he would come out and have their men hook it up so I could see it run. I walked out to it and it had a nice paint job, but as I examined the machine I started to see the Allen Cap Screws were full of dirt and painted over. So that meant they never rebuilt anything just cleaned it ad painted it. LOL. I walked up to the office and said to the salesman. What a bag of crap...rebuilt my behind...and walked out the door.

Earl Sigurd · Feb 28, 2018

I found a precision level on the carriage as it is taken in steps from head to tail shows a multitude of sins. Easier with an electronic level that you can zero if the machines attitude is way off.

Tips on what to test when buying a used machine to recondition or use.

Diamond

Diamond

Diamond

Diamond

Diamond

Diamond

Diamond

Cast Iron

Diamond

Banned

Stainless

Diamond

Diamond

Diamond

Stainless

Diamond

Cast Iron

Titanium

Diamond

Aluminum

Similar threads