Need Routine Maintenance Infor for Sirco PA-20 Lathe - Same as Summit 17-3 or 19

I just purchased a Sirco PA-20 lathe - picking up tomorrow and will be setting up in my shop over the next couple of weeks. There doesn't appear to be a lot of info on Sirco lathes on line but it looks identical to a Summit 17-3 an 19. The newer Summit 19-4 also looks the same externally but has a 4.125 spindle bore - mine is 3 inch, the same as the Summit 17-3 and the 19. I think both the Summit and Sirco lathes are probably made by a company called Potisje in Eastern Europe.

The Summit literature says the lathe has automatic lubrication to headstock, carriage and bedways - it also says the gears are in an oil bath. There appears to be two separate gear boxes - the spindle box gear box is a separate casting and has its own oil level sight glass - there is also a sight glass on the lower feed gear box.

I bought it from the son of the previous owner of the lathe who bought it used about 10 years ago - the owner has passed away and the son is not familiar with it. I was able to run it before I purchased and it seems to run very smooth and function properly with no unusual noise or vibration. This is my first lathe so I have a lot to learn but have a friend who is a tool and die maker and can help me out.

I don't have a manual for the lathe and am looking for any info related to general maintenance for this lathe such as

- if I change oil what type of oil should I use
- is there an oil lubrication pump and if so is there an oil filter to change
- what other routine maintenance or adjustments are required

Pictures below are from the internet of an identical lathe to mine






Any info and advice from someone who has experience with these lathes and/or has a copy of the maintenance and or operating manual for the Sirco PA-20 lathe or the Summit 17 or 19 will be a great help.

If you know where I can get a copy of the manual at a reasonable price that would also be great

thanks
Gary

I worked for a company when I was about 19 years old or so back in 1978 that had Sirco's. The company was Canadian owned hence the Sirco's and Toz brands. Much more common across the Niagara River. The Tags on the machines said Omnitrade machinery Toronto, Canada.
I don't know if Omnitrade is still around but it may give you a starting point. As I recall the lathes were made in Yugoslavia. They were excellent rugged lathes. I remember the headstocks use to get very warm when running but it never seemed to cause a problem. I worked at that company for 12 years and in all that time the Sirco's never had an issue, and they were pushed hard!

I have a couple of Summit 19" lathes. The recommended oil was Shell Turbo 68 (plain lubricating oil) in headstock and gearboxes, and Shell Tonna 68 (with tackifier) for the carriage. I don't know if you can even buy barrels of oil from Shell (in Canada) any more, but probably you can find a cross-over at other dealers.

The carriage has a plunger pump that operates once per rev of the carriage handwheel. The headstock has a gear pump, no filter that I know about, there will be some fines in the bottom of the sump if you want to do a wash out with kerosene or something. The feedbox is splash, but there might be an upper nipple on the feed box that feeds a chamber with oil wicks to various bearings in the feed box. There are oil nipples all over the place to lubricate things.

So far as maintenance goes, there are two clutch packs and a brake pack (which looks exactly like the forward and reverse clutch packs). Access for adjusting these is through a plate on the back of the headstock. You have to do the adjustments with the motor off (oily mess). These clutches have a ring with a lock pin for doing the adjustments. The lock pin has a little head on it that you can lift and give a 90 degree swivel so it will stay out of the way while you make the adjustment.

Generally, if the machine has been running properly, but no longer seems to 'snap in' when you push the engagement lever down (or up in reverse) then you need to adjust the appropriate clutch by only one notch at a time. If you go too tight, then you can no longer snap the clutch lever in (it is an overcenter snap feel), and you don't want to get abusive. It should cycle smoothly from forward to stop to reverse. You can really only get a feel for how it is actuating by running it while evaluating your adjustment (with the cover back on). I think the oil flow while running makes it easier to engage the clutches, while they can seem stubborn if you are trying to engage the clutches while the motor is off.

If the spindle coasts too long when the clutch is in neutral/stop, then the brake 'clutch' needs adjusting. You'll have to deduce which is which by watching the operation of the clutches, but the brake clutch will be very hard to adjust unless you actuate the forward or reverse clutch, which will free up the brake clutch detent ring and then you can adjust it. Only go one notch, even though it seems like it will readily go more than that, don't do it, it will makes things very sticky and stubborn to operate. These spindles do not stop on a dime with a heavy chuck to slow. It should slow down fairly rapidly. On my machine with 10hp three phase, it will accelerate to 672 rpm in about 3 seconds and stop in about the same time. I've got 2 12" chucks on the spindle, because I have one on the outboard end to support longer pieces through the spindle. I had to make up my own special backplate to do that, but there is quite a bit of spindle sticking out the back end to mount something on.

About the only other thing I've had to do was fix the hex in the sliding clutch lever on the carriage, which wore out and got pretty sloppy to operate. I found an extra deep, 6 point impact socket to fit the hex shaft (17mm). For that, I bored out the hex hole in the clutch lever and made a press fit of the needed portion of the impact socket. Works great as a repair, longer lasting than the original cast.

Thanks for the quick response HuFlungDung - a lot of great info. I got the lathe home today - raining so I just backed the trailer in my shop and took the tarp off so it wont hold any moisture in.

After giving a quick look over I have some basic questions on the controls if you have the time to answer a few newbie questions

On the headstock there are 3 levers as follows
- The right lever closest to the chuck has SLOW - NEUTRAL - FAST marked with a felt pen - When I ran the lathe before I bought it I did use that lever and was able to shift speeds from slow to fast and into neutral so that one seems pretty obvious but if there is more to it let me know.
- The center lever is a large round knob with a small lever - it has a sign over that says "before switching over stop the machine" - I assume it is to shift gears but no sure exactly what it does.
- the right lever has a label over that has 4:1 and 1:1 on it - also has a small plate with O in it and a plate over top with a table - 2 columns x 6 rows of numbers - again haven't figured out function.
- There is also a circle like a sight glass above the left lever near the top of the gear case but it does not have a line like a normal oil level sight glass ??- I pulled the end cover off and see there are two sight glasses on the end of the gear boxes as well as two drain fittings - I assume the upper one if for the headstock gear case so not sure what the one on the front panel is ?

If you happened to have a manual for one of your Summit lathes and could scan the page that shows the functions of the various levers and what each position is that would be very helpful

thanks
Gary

I don't recollect my manual's location

The right lever is a high/low range shift. You have to stop the spindle to shift. It can be balky, so you have to grab the chuck and rock it to complete the movement of the shift lever. This lever is one you'll move often to neutral in order to rotate the spindle by hand, because otherwise you'll be fighting the automatic brake.

The center round dial operates a rack which slides some gears around. It is a 3 position thing. Then the lever behind that gives you another choice of two speeds at each of the 3 positions. Add 'em all up, you should get 12 speeds.

The 'other right' lever is for the speed/direction of the output gear to the feed box. So you've got 1:1 for the standard range of feeds (right and left direction) then 4:1 is to speed up that output gear by 4x, giving the effect of cutting threads that are 4x coarser than is possible in the 1:1 position. This takes the strain off that output gear shaft.

The feedbox is very well designed, you can instantly shift between metric, inch, diametral pitches (for worm gear threading), without changing end gears. There is a plate on there showing one gear change required to cut 27 tpi, but pfft, who needs that one You can shift the feed rotary selector on the fly, as well as the selector lever behind it, at least at moderate speeds up to 970. Note that for metric threading you generally leave the halfnuts closed for the duration, and use forward/reverse on the clutch lever to change directions between cuts.

Edit: a gear change is required to cut the diametral pitches. I've never used it often enough to remember this tidbit, I have another lathe I use for that work.

HuFlungDung said:

I don't recollect my manual's location

The right lever is a high/low range shift. You have to stop the spindle to shift. It can be balky, so you have to grab the chuck and rock it to complete the movement of the shift lever. This lever is one you'll move often to neutral in order to rotate the spindle by hand, because otherwise you'll be fighting the automatic brake.

The center round dial operates a rack which slides some gears around. It is a 3 position thing. Then the lever behind that gives you another choice of two speeds at each of the 3 positions. Add 'em all up, you should get 12 speeds.

The 'other right' lever is for the speed/direction of the output gear to the feed box. So you've got 1:1 for the standard range of feeds (right and left direction) then 4:1 is to speed up that output gear by 4x, giving the effect of cutting threads that are 4x coarser than is possible in the 1:1 position. This takes the strain off that output gear shaft.

The feedbox is very well designed, you can instantly shift between metric, inch, diametral pitches (for worm gear threading), without changing end gears. There is a plate on there showing one gear change required to cut 27 tpi, but pfft, who needs that one You can shift the feed rotary selector on the fly, as well as the selector lever behind it, at least at moderate speeds up to 970.

Click to expand...

Thanks again for the quick reply and all the info - When I removed the end cover I did notice there was a set of gears on the outside of the gearbox - 4 meshing gears and the lover shaft has 2 gears on it - one is meshed with the one above and outboard one that is not meshed with anything - there is also an arm with a slotted hole o a radius and locking bolt in it connected to these gears - is that what you were referring to as the gear change for 27 tpi ?

thanks again
Gary

Yes, that would be where the gears would be changed. Did you get all the gears with the machine? The actual tooth numbers of those gears should be on that information plate.

HuFlungDung said:

Yes, that would be where the gears would be changed. Did you get all the gears with the machine? The actual tooth numbers of those gears should be on that information plate.

Click to expand...

I didn't get any extra gears - I now noticed there are diagrams on the inside of the end cover that show the different gear arrangements - the gears that are installed seem to be the correct ones for standard inch and metric according to the diagrams so probably OK for anything I will be doing.

I need help on another matter - the lathe has a 3 phase motor on it but I only have 240 volt single phase. I will need to change to a single phase motor or use a 3 phase motor with one of the electronic VFD's that will accept single phase input and give 3 phase output.

I thought it would be simple to just match the existing motor horsepower and rpm except when I pulled the motor out this morning I see the name plate had been knocked off and I don't know what HP or RPM it is. I know the previous owner was running 3 phase 240 volt in his shop using a rotary phase converter setup but that's all I know about it. His son told me that he converted it from 575 Volt when he got the lathe but wasn't sure what size motor was installed. It is T frame motor but based on the dimensions it could be anywhere from 3 to 7.5 HP.

From the specs I see online it looks like this model came with a 7.5 HP motor from the factory but cant find anything on the motor rpm. I tried to work backward from the chuck - max rpm of the lathe is 1500 rpm - I selected the 1500 rpm gear setting on the gear box, turned the input pulley and counted 3.3 revolutions of the input shaft pulley for each revolution of the chuck. That would mean the input shaft needs to turn at 5000 rpm to get 1500rpm chuck speed - does that sound reasonable ??

There is a 3 groove V belt pulley on the headstock input shaft - it is painted the same color as the lathe so looks original - it is about 6 inch pitch diameter - to get 5000 rpm input I would need a 3600 rpm motor with about an 8.33 inch pitch diameter pulley or an 1800 rpm motor with a 16.66 diameter pulley.

Do the rpms ad pulley sizes above make any sense to you ? - If you could confirm what HP and rpm motor you are running on your Summits as well as the pulley diameter on motor and headstock that would be very helpful for me to size the right motor

thanks again
Gary

I suspect you must have had the lever behind the rotary selector in the wrong position, because that has an effect on the gear ratio of about 3:1 since you have these options 670 and 220; 970 and 315 etc.

So it should be nearly 1:1 when you've got 1500 rpm selected (you've got 467 selected).

When I first got my first Summit, I had limited power so I put in a 5hp and ran it off a rotophase converter. It was a dog. Just going to real utility 3 phase was an improvement, but 10 hp was much peppier I'd suggest you go for the 7.5hp, since a lathe's main motor function is actually accelerating the chuck. Oh, it will use a little bit of power when its cutting, but those long windup times get pretty annoying after a while and you'll wish you had more. These lathes have pretty heavy spindles and large bearings because of the big bore.

Pulley sizes on mine are about 1:1 as I recollect, yes probably 6 inch OD. Lots of surface for belt wrap = long service life.

You'll want to get probably a 15 hp rated VFD, so as to avoid nuisance tripping of it on overload when starting up the spindle. Running a 7.5 hp on a 10 hp in order to get the 3 phase would be marginal, and you don't want marginal, because it costs more money to buy a 10 + a 15 than just a 15

I'm running 12" chucks, so maybe you'd be running 10"? You need at least that size to get a 3" through bore, I would think. I had to bore my chucks to get full capacity.

About the only time I ever used 1500 rpm was when I had a small collet setup on the spindle. That wouldn't take much power to get going, it was fun to run it.

HuFlungDung said:

I suspect you must have had the lever behind the rotary selector in the wrong position, because that has an effect on the gear ratio of about 3:1 since you have these options 670 and 220; 970 and 315 etc.

So it should be nearly 1:1 when you've got 1500 rpm selected (you've got 467 selected).

When I first got my first Summit, I had limited power so I put in a 5hp and ran it off a rotophase converter. It was a dog. Just going to real utility 3 phase was an improvement, but 10 hp was much peppier I'd suggest you go for the 7.5hp, since a lathe's main motor function is actually accelerating the chuck. Oh, it will use a little bit of power when its cutting, but those long windup times get pretty annoying after a while and you'll wish you had more. These lathes have pretty heavy spindles and large bearings because of the big bore.

Pulley sizes on mine are about 1:1 as I recollect, yes probably 6 inch OD. Lots of surface for belt wrap = long service life.

You'll want to get probably a 15 hp rated VFD, so as to avoid nuisance tripping of it on overload when starting up the spindle. Running a 7.5 hp on a 10 hp in order to get the 3 phase would be marginal, and you don't want marginal, because it costs more money to buy a 10 + a 15 than just a 15

I'm running 12" chucks, so maybe you'd be running 10"? You need at least that size to get a 3" through bore, I would think. I had to bore my chucks to get full capacity.

About the only time I ever used 1500 rpm was when I had a small collet setup on the spindle. That wouldn't take much power to get going, it was fun to run it.

Click to expand...

You are bang on again- didn't realize the lever shifted both ways - I had it to the right - when I shifted it left I came up with just over 1:1 - 10 turns of pulley gives 10.75 turns of chuck.

I have a 12 inch chuck as well so I was thinking it might be a good to decrease the motor pulley a bit to increase torque and improve acceleration by sacrificing some speed - I don't think I will have a need for 1500 rpm - thought setting up the pulleys for 1200 rpm chuck speed max might be a good compromise.

thanks again
Gary

With a VFD in the picture, you've got lots of speed options. You'd probably use +/- 25% frequency shift using every gear as a 'range gear' of sorts. So you could still readily get to 1500 if you needed to. Yeah, I can't see too much of a downside other than compromising a bit on belt life with the smaller sheave on the driver.

As I recall, when I added the rear chuck support to my lathes, I made a backplate with a hub that slid over the tail end of the spindle. There wasn't a lot of room to spare (3/4" wall thickness of the hub) so I had to reduce the working diameter of the top sheave a little to get that in there. So I probably have a bit of overdrive, but I've never cared to document the difference. You might have more room on a 17" machine, although I'm not sure how different the headstock is on the 19". Adding that rear chuck made the removal of the end cover more difficult (obviously) and you have to get in there to oil the gear bushings on all the idlers. So I upgraded all the idlers by taking them off, boring them for dual ball bearings and so I never have to oil them anymore. I also took and sawed the top cover horizontally at the height of the spindle centerline, so I could lift that off to fasten on my backplate.

I expounded a bit extra there because I feel it is important to have a rear chuck for the sake of supporting long bars and tubes, stuff that might be 4 to 8 feet long, or even longer (with a floor steadyrest). That is a lot of stress on just one chuck to support that kind of thing, and it gets to wobbling and things get dangerous very quickly. An alternative would be a set of spindle liners, I guess, but it takes a lot of liners to handle everything from 1/2 up to 4.125 (in my situation) and some stuff is pretty rough (maybe even a little crooked) for a liner, so if it doesn't fit tight, it will still get to rattling and clunking around.

I generally run a lot of finished material (ground and polished whatever) so I don't use roughing jaws (except for the bigger 4 jaw that comes with the lathe) so as not to score up the bars. So using a front and rear chuck with smooth jaws generally provides enough grip to stop the bar from wriggling its way through the chuck on a heavy cut. This is a constant issue with using only one chuck, along with the wiggle waggle of the bar held 'not too well' in a single 3 jaw: it just worms its way through.

Thanks for the additional info last week - was busy with work and didn't get back to getting more familiar with the lathe until the last couple of days. I was able to get a 7.5 HP single phase motor from a friend at a reasonable price - its a Leeson, 230 Volt with a service factor of 1.15 and full load current of 33 amps. It will simplify the electrics for me - I have all the other parts around I need to hook it up single phase.

Installed the motor on the lathe today with a pulley I calculated would give me the 1500 rpm chuck speed in the highest gear. I measure 1400 rpm on the headstock pulley with the clutch disengaged so I just be very close to 1500 with the small overdrive gear ration in the 1500 rpm setting.

The lathe ran fine at the lower speeds - 672 rpm and below - when clutch engaged chuck gets to speed very quickly and doesn't seem to effect motor speed much. On the 970 setting it did slow the motor down enough that the start capacitor switch kicked in briefly but got up to speed within a few seconds and ran fine.

In the 1500 gear it slows the motor down almost to a stop - tecapacitor start switch kicks in and it very slowly starts to ramp up but overloads kick out long before it ever gets up to speed - I tried engaging the clutch slowly to let it build up speed gradually but still trips the overload and would probably overheat the clutch pretty quickly.

I could see if I can increase the overload size but I don't think I will be able to run the 12 inch chuck at 1500 rpm using this single phase motor with capacitor start without a lot of stress on the motor and the lathe clutches - haven't worked much with 3 phase - I assume a 7.5 hp 3 phase motor would be more forgiving to a long speed ramp-up time since they don't use capacitor start ???

When I originally got it with the 5 hp motor I didnt think I would ever need 1500 rpm for my usage and planned to change the drive pulley to give me something in the 1000 to 1200 rpm top speed. I think I will still do that - if I reduce the motor pulley by about 30% that will give me a low speed of 15 and top speed of 1050 - all the speeds in between are almost identical to the original speeds except 1 gear lower - 31.6 becomes 22, 46.7 becomes 31.6 etc. Also there is no chance of selecting the 1500 rpm gear by mistake. The smaller drive pulley should improve the acceleration in all the gears and prevent

Do you see any downside of this arrangement other than the chuck speed settings will not match the actual speeds ???

Blueacre, I will not be much help to you because of my memory lapse, but I used to own a PA 20 and did the exact same thing as you. I too installed a 7.5 hp single phase motor and never had a problem with getting the chuck up to speed. by slipping the clutch.
I see HuFlung has got this figured out for you though, as I had to just keep experimenting with different things to learn how to run mine since I was without a manual too. You would think I should have retained some of that info. since it was self taught, but sadly, nothing is coming back to me.
I sure miss that 3" spindle bore though and the standard and metric threading.
Dave

Blue,
I have an extra manual for my 19x80 Summit. It's yours if you want it. It's not the exact same machine as mine, but it may be helpful. You can probably get the exact manual from Summit at summitmt.com

For oil, I used Mobil Heavy Medium. You will need at least a 5 gallon pail for a full change. If it's been sitting for 10 years, I would definitely drain it, flush it out, and refill before doing any real work. I'd also do a good cleaning of the drip pan (you will see it once you pull the headstock cover). Make sure you clean out the drip line immediately behind the sight glass. This is how you check to make sure the headstock is getting lubed. It takes a minute or two for the oil pump to fill the drip pan and for the drip line to start showing oil. There are two additional sight glasses for the oil levels.
The headstock and gearbox have separate fills, drains, and sight windows. You win a prize if you can find both sight glasses. (There's the obvious one on front of the gearbox. The 2nd one is tricky to find. Look at the headstock end of the lead screw, and bring a flashlight). For some reason, the manual gives the proper amount of lube in kilograms. If yours is like mine, the gearbox sight glass will be clear enough to show the proper fill level. The upper headstock... maybe not. I filled mine, and ran it a bit with the cover off. If it gurgles, add another quart or so. You can't hear it gurgle with the cover on, though.
Summit still has lots of parts for these, including all the little placards. If I read your post correctly, you have the same 5 position lever which vexed me a bit when I first got the Summit.
It has reverse feed high and low, center neutral, and forward feed high and low. These are marked as 1:1 and 4:1. Again, this is for the feed, NOT spindle rotation. That's the carriage lever: lift up for forward, and push down for reverse.
Hu was kind enough to give me some pointers for clutch adjustment. I have mine mostly right, but I think it may be time for new clutches. It's a job I have put off for a few years, but will probably do this year.
Did I read your post correctly? This is your first lathe? Treat it with an abundance of caution. It's easily powerful enough to pull you into the chuck or part, and mash you into a pulp.

>>Do you see any downside of this arrangement other than the chuck speed settings will not match the actual speeds ???

Is there some reason you are not using the Summit's 3 phase motor on a rotary phase converter? Sounds like you already have the parts...

I don't run my Summits at 1500 rpm very often takes too long to get there and too long to stop with 12" chucks. There is also the tendency for a bit of vibration at that speed. I don't think it is worthwhile striving to get it by changing the ratio, it isn't going to do much for you without a 10hp 3 phase motor. I get by running anywhere from 220 to 967 most of the time, so it's a 5 speed lathe

You're better off getting a 6 inch chuck or a collet chuck if you want to run fast, then it will perform more satisfactorily. Build yourself a wooden cradle to fit the bed and the 12" chuck so you can easily remove the chuck and slide it off the camlocks without denting the spindle taper register.

Do not ride the clutches unnecessarily, as that sort of thing can warp the clutch plates. The clutches are all steel plates, with oil feed through the center so they can tolerate a bit of slip, but if you warp them, then you'll not get them to release properly because of the limited travel for engagement. A little bit of warp on half a dozen disks will take up all the free clearance. So then you'll be backing the clutch adjuster off to stop it from spinning in neutral and you won't get it to snap in when you actuate the clutches.

>>I get by running anywhere from 220 to 967 most of the time, so it's a 5 speed lathe

I've been doing a lot of internal threading lately, so I'm using the slower speeds, like 67 and 97. I'm just not brave enough to thread to an internal shoulder at 220RPM.

Dan

Dan Cassaro said:

Blue,
I have an extra manual for my 19x80 Summit. It's yours if you want it. It's not the exact same machine as mine, but it may be helpful. You can probably get the exact manual from Summit at summitmt.com


Did I read your post correctly? This is your first lathe? Treat it with an abundance of caution. It's easily powerful enough to pull you into the chuck or part, and mash you into a pulp.

Click to expand...

Hi Dan, thanks for all the info - yes it I my first lathe and I plan to be very cautious. I grew up on a farm and have a healthy respect for rotating equipment. I did learn to run a smaller lathe in high school but that was many years ago. Fortunately I have a friend who is a veteran tool and die maker with many years of lathe experience and will help me learn.

You mentioned you have an extra manual for a 19x80 - I would be glad to pay for it - let me know how much you want and I will be in touch

thanks
Gary

Dan Cassaro said:

>>I get by running anywhere from 220 to 967 most of the time, so it's a 5 speed lathe

I've been doing a lot of internal threading lately, so I'm using the slower speeds, like 67 and 97. I'm just not brave enough to thread to an internal shoulder at 220RPM.

Dan

Click to expand...

I came to the same conclusion myself over the weekend - if I leave the pulleys as they are and just not use the 1500 rpm setting it should be fine for my use. If I did reduce the motor pulley size the chuck rpms will not match the dials on the lathe and there is greater chance of belt slip with the smaller pulley. I am only running 2 B Belts instead of the 3 it originally came with.

Blue,
I sent you a PM.