Sieg SC-4 Lathe 8 1/2" x 16"

[philjoe5]

I was walking through my huge 20 " x 30" foot shop a few weeks ago and discovered I had this nice blue workbench



Well I had to find something blue to put on it, right?  A pot of blue flowers would look nice, but I was informed the season has passed.  So I found this instead:



It's the Sieg SC-4 8 x 16 bench lathe sold under various badges.  It Looks good on that bench and I can always use another lathe.  This one has an ER-32 spindle mounted collet chuck which closed the deal for me. I checked runout with a few drill rod test bars and found TIR's of 0.0005" and less (not measureable by my indicators).  This is quite satisfactory to me for a machine with a retail price of $1600 USD.



All the features of this lathe are impressive and it's by far, the best import lathe that I've owned out of the box.  I had owned the import 9 x 20 and own the import 10 x 22 as well as a Logan 10 x 24, so this is lathe #3.  Time will tell how it stands up but it's off to a good start.

I'll post updates when something good or bad happens

Cheers,
Phil

[b.lindsey]

Congrats Phil...nice looking machine too!!

Bill

[Kim]

Nice addition to the shop Phil!
And while the flowers would have looked nice, I hear its best to stay in season.
Luckly, lathe's are always in season! 
Kim

[AussieJimG]

Dribble, dribble, dribble

Jim

[steamer]

Congrats Phil...nice looking machine too!!

Bill

Yes congrats Phil!....do keep us informed.

Dave

[mechman48]

          

George

[HobbyNut]

Nice lathe 
What 10 x 22 do you have? and how do you like it?

[sshire]

Ohhhhh! That is excellent!

[philjoe5]

PatO,
I have the Grizzly 10 x 22 lathe and it is my main workhorse for turning my large workpieces.  I've modified it so my lowest speed is about 80 rpm. 

I'm evaluating the 8 x 16 lathe for use in a Makers Group that will introduce machining to anyone interested or to someone in need of metal parts for a device they're making.  So far, it seems to be quite a capable machine.  Along with its desirable features it has all the quirks of a new machine but I'm quickly adapting to them. 

And heck, it's a well made lathe for its price, what's not to like

Cheers,
Phil

[Don1966]

Nice find PHIL and congrats. ........................ 


Don

[HobbyNut]

PatO,


I'm evaluating the 8 x 16 lathe for use in a Makers Group that will introduce machining to anyone interested or to someone in need of metal parts for a device they're making.  So far, it seems to be quite a capable machine.  Along with its desirable features it has all the quirks of a new machine but I'm quickly adapting to them. 

And heck, it's a well made lathe for its price, what's not to like

Cheers,
Phil

So you are in a Makers group. That's interesting, as I am a subscriber to the Make magazine and attended a Makers Fair this Summer. I find it amazing how a lot of us have the same interests. I am into model planes, boats, cars, helicopters, and engines, as well as full size motorcycles, hot rods, car racing and cooking!! 
My monikor "HobbyNut" is very fitting!!
I am looking at getting a 10X22 is the reason I asked. Mine will be the CRAFTEX brand here in Canada.

[philjoe5]

Now that the smell of fresh grease has wafted away, it’s time for a reality check with this lathe.

Things that surprised me:

There isn’t a carriage lock in the usual sense.  To lock it, disengage the lead screw from the gear train and engage the longitudal powerfeed. 

There isn’t a threading dial mount on the carriage.  One reason perhaps is that there’s a metal shield protecting the leadscrew.  However, the motor is a DC variable speed and it has a spindle brake so when you hit the stop button, it stops immediately.  So you can thread by hitting the stop button at the end of the thread, retracting the tool, reversing the carriage to the beginning, etc.  I haven’t tried it but I think it should work just fine.

Things that impressed me:
A calibrated carriage handwheel in 0.020” increments.  Not a DRO but easily capable of getting a turned length to within 0.010” which is more than acceptable in some cases.

The ER-32 pass through collet chuck.  The worst TIR I’ve seen using the ER-32 collets was 0.0015” on a piece of 9/16” diameter stock.  Mostly TIR is 0.0005” or less.

The drive mechanism for autofeed is positive.  When it’s engaged, the carriage goes forward only.  The simple half nut engagement on many of the Asian lathes can cause the carriage to jump back about 0.020” when the half nuts are engaged, which can be annoying at times.

Variable speed is a joy to use.

It seems a capable machine but can it make precision parts?  I’ve built many model engines, mostly steam engines.  The last engine was an IC engine.  In my experience the valve cage and valve assembly is challenging to make, requiring one to obtain parts within 0.0005” of a target diameter.  Additionally, the long stem of the valve must be turned in steps that require moving the workpiece from its holding device in a few, if not several steps.  A 3 jaw chuck won’t do, and I can’t image trying to use a 4 jaw chuck to accomplish it. 

I have the ER-32 collet chuck for workholding to use for this job. 

I start by turning the end of some 3/8” stainless down and threading it 4-40 using a tailstock dieholder.  Next, I turn a 3/8” length down to 0.124” to make the first part of the stem.  This provides clearance for a fixture used to hold the threaded end. 



The fixture is screwed onto the end of the valve and clamped in a live center drill chuck.  The remaining ¾” of the stem is then turned down to 0.124”. 



The valve seat is cut at 45 degrees.  Then the valve is lapped in a valve cage with a drop of metal polishing compound.  (Ignore the aluminum prototype on the left)



The valve is parted off and  holding the valve stem in the collet, the face is trimmed to length.

The valve cages were made from bronze.  They are reamed 0.1245” on the guide end, and drilled with a “Q” drill on the seat end.  They are turned to two diameters, 0.312” and 0.375” to fit into the cylinder head.  I cut the ports by milling a slot before I install them in the cylinder head.  The seats are cut at a 45 degree angle using a boring bar.

Three sets of cages – valves are shown here along with a threaded spring keeper.  The keeper is locked in place with a jam nut.



It’ll be a month or so before I get to test these valves but they appear nicely finished and I don’t anticipate problems.  I’ll report back when they’re tested.

I purchased the optional A2Z QCTP with this lathe.  And contrary to a lot of bad press I’ve seen about anodized aluminum tool holders it performs very well. 

The lathe controls work well, there’s plenty of oil ports, and the finish on the valves and other steel parts I’ve turned is good.  A useful light bench lathe.

Cheers,
Phil

[wheeltapper]

QUOTE
'snip'

It seems a capable machine but can it make precision parts?  I’ve built many model engines, mostly steam engines.  The last engine was an IC engine.  In my experience the valve cage and valve assembly is challenging to make, requiring one to obtain parts within 0.0005” of a target diameter.  Additionally, the long stem of the valve must be turned in steps that require moving the workpiece from its holding device in a few, if not several steps.  A 3 jaw chuck won’t do, and I can’t image trying to use a 4 jaw chuck to accomplish it. 

'snip'
QUOTE

If it helps at all I have the Chester version of this lathe and I made the Nemett Lynx engine on mine.
Roy.

[philjoe5]

Roy,
Yes, I think it helps.  Good old iron is getting hard to find everywhere so any source of a good bench lathe is always welcomed.

Cheers,
Phil

[philjoe5]

Just to close out this thread I'll point to this recent post:

http://www.modelenginemaker.com/index.php?topic=4802.0

It seems as if this lathe is capable of making parts demanding the precision required for valves and valve guides for an IC engine.  Just wanted to complete this tool review.  IMHO, you can make all kinds of claims about a tools ability to perform but an example of what you can make with it is best.

I hope readers find this useful

Cheers,
Phil