My "NEW" Prazi SD400 Lathe build

RaisedByWolves

Mangler of grammar, off my meds.
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2nd one for me.

I found this offered on FBMP for a rather high price and the seller claimed it was new. It certainly looked good in pics, but at 2K it was much too expensive even if it was new. I haggled with the seller over this for more than a month and had it in my head I was maxed out at $1100.

After 6 weeks the seller gradually dropped the price down to $1400, but told me in a PM he would take $1200. Being afraid to lose it as it was now in line with offerings from PM and LMS, I jumped on it. Knowing the quality, both in manufacturing and design I couldn't resist the opportunity to have a brand new lathe to build out into what I had planned on for the first SD400 I bought.

A clean slate so to speak.


And other than some shelf wear, this machine is indeed brand new. Never made one chip as hard as that is to believe.


Here it is next to its little brother the day I got it home. I initially thought the brown on the compound was rust, but it was only WD40 mixed with sawdust.



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Little staining from the WD40 is all there was after a wipe down.

Doesn't look as bad in person, the camera picks up every bit of color.


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There are no chips or signs of use anywhere. The brown spots are WD and sawdust.



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The flaking on the ways is still pristine. This is before it was even wiped down, the entire bed is pristine.


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My plans so far are are for a Custom Crafter motor and controller upgrade, tailstock thrust bearing and upgraded handwheel and an electronic lead screw kit. Im not sure what ELS kit Im going to use as of yet. The one that Clough uses dosent inspire me, but this guys kit looks promising.





So, first things first. Im kinda back on a budget after putting out the money for this so I have to work at the lower cost upgrades first. No big deal as the first modification Ill be making is similar to one that made a huge improvement on my SD300, radial and thrust bearings in the tailstock. But with this lathe I decided to upgrade the tailstock handwheel to a larger, heavier (10-12 times the mass of factory handwheel) cast iron handwheel.

The need for this addition to the tailstock is that with these smaller machines, the drilling forces at the handwheel feel like you're pushing a much bigger drill than you really are. This is due to both internal friction in the tail stock (Plain bearing made of steel) and the relatively small size of the handwheel. Having a larger and more importantly, heavier handwheel also helps release the tooling from the taper when changing tooling.

On all but the smallest lathes, ie under 9" the handwheel has enough mass so you can "Whip" the handwheel in reverse, and let the inertia of the heavy wheel knock the tool out of the taper. This also helps when retracting the drill from the hole as with a heavier wheel you get more turns when you whip it, again, due to the mass.



I looked at a lot of different offerings for cast iron handwheels and really didnt like many of them. Wrong number of spokes for the size I wanted, cheap looking castings, low quality finish....

Then I found this from a company called Fixtureworks.



And its perfect!



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Almost an inch bigger (.800 and change) but still at a size where it wont look like clown shoes on this size lathe, and it will add a nice "Big lathe" look to the machine.

Before I could begin on boring the bearing pocket for the radial bearing I needed a carriage stop. I threw together a basic carriage stop made from a block of aluminum and a 14-28 bolt. Nothing fancy, just something that will work.




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Next I found some appropriately sized bearings on A-zon and got to work.


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I set up the 4 jaw and indicated the part in and got out my best available (At home) boring tool. It has a nice sharp brazed carbide insert and as I found out, far too much stick out for the length and diameter of the shank.


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It just wanted to chatter and make god awful noises, so this had to go.

So I went with my 2nd choice, an Edelstaal 1/4" boring bar and insert. Up to this point I hadn't used this boring bar and didn't know what to expect with it only being 1/4" in diameter. I love the whole line of insert tooling, well, everything but the price, but I got this in another lathe package and hadnt tried it yet. I have good results with the other turning tools in the line, and with no other options I dressed down the insert to fit the into 10mm hole in the handwheel bearing block and got to work.

Oooh, tiny!


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Tiny, but I was better able to eliminate excess stick out with this one and it performed very well.


Using a snap gauge (Sue me) to sneak up on the correct hole diameter.


Almost there....


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And done. Got a really nice finish and a nice slip fit on the bearing.




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Congratulations on a nice score! I look forward to seeing the modifications.
 
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