DIY fixed steady for a lathe: CQ9325 10 x 18" (250x450mm)

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PekkaNF:
Let the show begin :clap:

I have tried to read the da-rulez and I figured I had invite critique?
http://madmodder.net/index.php?topic=2527.0
"Also bear in mind, if you ask for comments or critiques... you may not like what you hear. But thats also what this board is about... without constructive criticism, someone may not finish a project or worse yet, get hurt."

I don't have a very thick skin, but luckily I don't understand all the fines either. And please bear with me: I have dyslexia on all languages, I read fast and understand most of it, it's mostly writing: I'll put letters slightly on wrong order or use "close" letters and I even don't see it. My speciality is to "skip" few important letters every now and then...I'm trying speller, but it gives me ridiculous suggestions - normally opposite I want.

Anyway everyone have to start somewhere if someone sees that I'm making something completely wrong I'm happy to be corrected.

The trouble I had was manual circular milling - first time I ever tried but there is probably a better way of doing it. In the bright side:
* It workked, although it was slow, but it was a deep hole and I could not run mill fast enough
* End mill stayed shar and it was very cool (immersed on coolant all the time)

then again:
* Should I have used an slotdrill? I used four flute end mill that has a limited plunge ability. I used very gentle ramp down (slow Z with left hand, while winding willies out of rotab w/right hand.
* Probably should have gone bigger and produced more swarf, this "deep", would have improved D/x
* feeds are hard to handle well manually, on the other hand I felt all the time how the cutter was cutting
* Made a bad choice with coolant - heard it used, I had to have a try. Next time I'll rig shopvack with narow spout

Maybe I should have tried something completely different? I could not see myself using holesaw, I don't thik chips would have come up and I dont like to peck drill on kneemill without pinole. On bright side: I would look soon like govenor of California when he was young.

But that was yesterday. Today I have to consider arms.

If I understgand right arms:
* better be softer than piece to be turned
* Should not easily weld on that piece - this would exclude most aluminiums

I have 10*10mm square brass rod and then probably a bronze plate that is 8-9 mm thick....from junk-yard (alhough they don't call it that anymore they all are recylcle something). Both feel smallish, I'll probably lash up someting temporary and fix ita lter when I'll get something better. Now How do I keep witnesmarks when I take it off the rotab?

Anything I should know about the arms. Most builders don't go into very many details here on materials and shapes. V-on the end and everyting reasonable square? That's it?

THank you,
Pekka

AndreasL:
:thumbup:

Very nice I must say.

Keep us updated about your progress.

PekkaNF:
Thanks. Hey, I was looking for a advice...typical Finn.

Anyway, didn't had a change to do much on this one.

I have mixed feelings about the arm materials:

1) I have 10*10mm brass rod, but that is probably way too small, unless I made 4 mm slot for M4 retaining screws....
2) Second choice is mystery bronze/brass, probably I could make 8*15 mm arms, where I could use M5 retaining screws...

Any toughts? Should I just put some OD25 mm tempering steel rod on the lathe chuck and spin it 750 rpm and advance a piece of both materials on the lathe tool holder towards rotating piece and see which fails first?

Thanks,
Pekka

Henning:
Since you asked for advise...

I'd say some sort of brass would be good for the arms as you call them. I do suggest you take a good long look at incorporating ball bearings though.
Have a look here to see what i mean: http://littlemachineshop.com/products/product_view.php?ProductID=2419&category=1

Actually, thinking it through, most arms are probably bronze of some sort...

PekkaNF:
Thanks. I'm not a big fan of inrunning nips - they tend to draw in all sorts of debris that is produced on the lathe. I have some cam rollers, I probably could use them if I had to.

I'll be using this on steel first, I think I'll aim to it and if it comes to softer metals I'' try first nippin brass shim or something between arms and a rotating member.

I have been toying with an idea of using a large deep grrove ballbearing and a spider or sort of pot chuck instead of arms on a fixed steady...I'm ALMOST convinced that it could work with softer materials and if done with extreme precision. I'm not there yet.

Still drawing right size of arms - that is a bad sign: If I dwell on something too long, it usually fails first time. I'm jinxed!

Pekka

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