Oh boy, I did it again! PRAZI SD400.

[RaisedByWolves]

I must be broke in the head.

Found this guy about 3hrs away and it wasn’t too expensive so I cobbled together the cash and went down and had a look.





When I got there I met the couple who owned the business. It was an aerospace company that was liquidating as none of the heirs wanted to run it.

Got to talking to them and in looking the machine over I discovered a big problem. This was a surprise to them and a bit of a disappointment to me as I already have 3 project threads going.

RBW's adventures in tiny Industrial machines. Prazi lathe and milling machine score.

I have lusted after machine tools since 9th grade shop when I made a working cannon, and much to my shop teachers dismay set off all of the car alarms in the neighborhood with it outside of the shop doors in the faculty parking lot. He thought this was impossible for a kid like me, but I had...

www.hobby-machinist.com

Prazi BFE65-Littlemachineshop Big Mill table Frankenbuild, spin off thread.

This thread is a spin off of the following to keep things from becoming cluttered. Lathe Mill score thread. I got this mill head in a package deal as posted in the above thread but the milling table/base was not included. Having read everything I could find about this combo and working as a...

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Time to fix up my old Steinel SV4 milling machine.

If anyone needs a manual for this machine you can download it here. Takes it a bit to download so be patient. https://onedrive.live.com/view.aspx?resid=FF09154D1189EB47!201 What is a Steinel mill? Mine looks like this. This is where it sits as of now. I had to drag it out of its...

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Oops. Baby makes 4!

Craftsman power hacksaw rebuild.

Trying to cut things to length in a small shop can be tricky. I have a small bandsaw, but cutting round stock can be problematic and the blade speed on these is generally too high to cut steel with anyway. I had a small Dunlop branded unit years back that was in pristine condition, but I sold...

www.hobby-machinist.com

Anyhow, we found that the lathe had suffered a crash at some point and the saddle traverse pinion gear shaft was bent and not allowing the saddle to traverse. It would travel, bind for a bit, free up and then the gear would skip.

Yeah, it was that bad.

Still, finding this I was in a good position to negotiate and I scored the lathe, tooling and this sweet KENNEDY workstation for $1100. That was about a 2/3 of their asking price which I would have gladly paid if the machine were in good running condition.

Got the lathe, stand, 3+4 jaw chucks (Prazi 4” 3 jaw and Bison 5” 4 jaw) a collet nose and closer and steady rest plus several indexable tool posts, assorted carbide tool bits and a heavily misused set of boring bars meant for a boring head that they were just screwing down in the tool holders.

I think a set of collets (first pic, bottom shelf to the left) and a couple of the change gears got lost in the shuffle and I’m hoping they find that along with the missing travel rest, but as it stands I’m ok with this.

It was raining like hell that day so I bagged the lathe in huge industrial garbage bags and left the bench nekkid to rely on all the oil soaked into the maple top to protect it from the elements.

Beauty shot of it from when I first got it unloaded.








Literally minutes after getting it home I got the shaft bent back enough with a C clamp to actually move the saddle well enough I could work on it.


The gear probably isn’t salvageable, but should be cheap enough to buy new, and the shaft I can make from tool steel and support better for less backlash.


Here’s the offending gear.

Look at that stick out!





And the C clamp in place attempting to bend the shaft back.







When doing any type of guerilla shaft straightening like this its important to know that you will need to bend the shaft past straight as it will spring back a bit. I used the handle of the C clamp as a crude (Very crude) micrometer dial, taking it to one point in the rotation after contact and checking, then taking it further and further as needed to get my intended result.

I couldn’t get it perfect by a long shot so it will still have to come apart, but it looks like they were greasing these gears so it needs disassembled for cleaning anyway.



Junky, funky lead screw was nice looking once the schmutz was cleaned off.








The 4 jaw looks like new and the 3 jaw looks good but it also will be taken down and cleaned.

 

[markba633csi]

That's the biggest model they made I think and probably the best- congrats

 

[RaisedByWolves]

That's the biggest model they made I think and probably the best- congrats

Thanks.

This is the biggest model they made in this design, but they did make an SD500 which is a true geared head lathe with a 10" swing.

Brochure for the entire line at the time along with the "Artists rendering" exploded view Ill be *****ing about in a moment.





SD500 specs. Far as I can tell this was around $10K when this was published.

And as good as the Germans are at making tools and machines, they absolutely sick at making literature. Here the tailstock travel is listed at 2", when that is the travel for the SD300 and the SD400 writeup is identical to the SD300 when the actual specs are not.









Got a little more done tonight and hit a wall.

I started trying to disassemble the apron to get at the bent shaft and gears for cleaning and initially thought I might be able to remove it without needing to remove the lead screw, but nothing worked.

I even consulted the manual, which is one step above horrible. Cartoon like drawings with no definition (Is that a screw head or did the artist flinch) so that was no help. I picked around enough to realize everything that looked like it might be a set screw that would unravel the whole thing were just pins and blind holes.


Looked sad at this point. But man....that lead screw.....






You can see I got everything almost far enough apart to slip the half nut over the lead screw, but it just wasnt happening.








So with that not working I went after removing the lead screw from the headstock end. Initially I thought I saw another of those bastar d C clips they use on the smaller lathes.

The rounded protrusion on the left of the spanner nut.




But it wasnt, it was the nylon locking collar crimp. I got the gear off to find that this machine may have been built on a Friday.


Look at that old world craftsmanship!








Once I had the taper pin tapped out I was faced with this nyloc nut and nothing to drive it with. I could have just grabbed everything with vise grips and disassembled it tonight, but I wouldn't be able to look myself in the mirror after buggering everything up like that.

I want to make it better, not worse.

I took some measurements and I'm going to make a drive socket for it tomorrow and a clamping block for the plain portion of the leadscrew so I can get some purchase on that and get the nut off.

 

[markba633csi]

Use an Ideal clamp around it then you can loosen with pliers without scarring it up
But if you want to make a proper tool that's fine too

 

[Firstram]

Use an Ideal clamp around it then you can loosen with pliers without scarring it up
But if you want to make a proper tool that's fine too

I've never even thought about using hose clamps as plier guards. What a great idea!

 

[tq60]

Use impact gun, it will zip it off easy.

Sent from my SM-G781V using Tapatalk

 

[RaisedByWolves]

Use an Ideal clamp around it then you can loosen with pliers without scarring it up
But if you want to make a proper tool that's fine too

Had to look up “Ideal clamp”, but that might work. Vice grips with a piece of leather works well too.

I’m a toolmaker so I tend to make tools for fun while waiting for engine earring to figure out what they want me to do.

I went quick and dirty (and I feel dirty) and used a piece of black pipe that was close in size to what I needed and did a thing.

Normally I would use some type of tool steel for this as it’s much more machinable, but I figured I’d see how this would turn out if I just winged it.


Turned out it looked like a bag of smashed assholes.








Cleaned up OK I guess. Normally I make stuff like this out of O1 or A2 if I have it in a small enough size, but the pipe was handy so we’ll see. I like making it out of good material so I can have it for future adjustments, but This should do.

A little filing, a 1/4” cross hole, the worlds longest 1/4-20 bolt and…. Well, it’s not aweful.





Note to self, wipe the greasy finger prints off of lense when using flash.



.

 

[RaisedByWolves]

Got my custom made wrench home yesterday and it fit perfectly.

Didn’t need to make a shaft wrench after all as there was a very convenient hex section on the end of the lead screw to put a wrench on.






I don’t know what grease or assembly lube they used on these machines but every single nut/collar/pin has required some heat to remove.

Not much mind you, I can hold the parts in my hand afterward usually, but about 250* loosens everything up.

Here the machine is turning to keep the adjacent plastic gear happy.









After it wouldn’t come loose and having applied heat, it still wouldn’t budge, but what I thought was a solid milled hex on the other end dig give up, and it turns out I didn’t need to make that wrench after all.


Oops!






With that crafty lil nut off the apron could now escape from its lair.








And then I saw this!

Y.U.K!!!!!









This is why you dont blow your machine off with compressed air.

Every crevice was packed with swarf.








After my initial disappointment at this state of affairs I’m actually glad it was lubed improperly (I’m thinking some type is spray lube in a can) and blown off as other than the bent shaft, a good cleaning uncovered near pristine wear surfaces! Parts cant wear if they aint touching!


Before and after cleaning the half nuts.

This is after some of the swarf was already washed off mind you.










Upon further inspection I found the half nuts to be actual cast iron and showing no signs of wear (Wears like iron!). No Zamak or brass used for these just tells you how much value you get with these machines and why they cost so much. I was actually expecting these to be brass at best.

Both sides of the same nut.








I’m kind of thinking that with all that crap in there the machine would no longer feed properly and combined with the bent shaft its possible they just stopped using it at some point.



Everything all cleaned up and ready to go be modified….. heavily!

 

[RaisedByWolves]

Got the compound off and degreased well enough to find a couple instances of malfeasance.

The end of the top slide was run into the chuck at some point.











Not a huge deal, but since I’m going through the entire machine I figured I might as well clean this up.

Cleaned up at .055, looks much better.







Then it was on to the compound itself. This was also run into the chuck (sigh…..) and again, not a huge deal, but it’s ugly.







I milled the top slideway and cleaned it up. This took .075, and while there is still a small mark, to go further was to go into the realm of diminishing returns.

Not much of this was affecting accuracy, but I did gain back a little rigidity as whoever cleaned up this crash did a **** poor job on the gib-side way. It looked to have been just blasted off with a hand grinder rather than having some take the time to do a good job. I beveled it with the center drill and I was able to get rid of most of it.



The compound is held down to the T slots on the cross slide by a retaining ring and 4 bolts and T nuts, and of course this also took a hit.

I simply beveled this with a large center drill as the 81* included angle was closest to what the boogered up areas angle was. A 90* cutter would have been fine also, but this left a bit more meat on the outer edge and felt like the better way to go.








All cleaned up and looking pretty.