Bazmak diary of a 7 x 16 sieg mini lathe

[bazmak]

PART 11 The next project is work in progress.The idea came to me during one of my design sessions.(The time between getting into bed and falling asleep.)
Some of JOHN MORANS mods frequently mention making new parts rather than modifying existing,so the machine can be be refitted back to the original
On his compound slide bearing mod he mentions machining the leadscrew,but for this you need a 2nd lathe?
I obtained a piece of 50sq bar x 43 lg,drilled thru 6dia and then opened up and tapped M10 x 33 dp,then faced off both sides to length 40mm
I drilled and c,bored 2 holes to suit the 2 M6 tapped holes in stepped disc on the X slide. Remove the X slide (40mm high) and fit the new block,the tool post can then be fitted on top and basic turning done without the compound slide. Next thought was to make another block faced to 40mm lg and drilled clear 10 mm
This can then be mounted as a dedicated tool post and machined as required.I plan to mill a 12w x 2mm dp slot at 5 degrees for a piece of parting off toolsteel
The 5o angle will help set exact centre height and the top rake will not be required ground. I plan to bore out the opposite side (say 1/2" to fit standard boring bars)
machineing from the headstock with collets will line it up at centre height More could then be made as cheap Q/Change toolposts
If the original 40mm spacer block is reduced then larger section cutting tools can be used.My tool centre height measures .350, therefore i use 5/16" tools or machine down 3/8" tools.Taking 0.150" off the block would allow 1/2" cutting tools. (to be continued)

 

[bazmak]

PART 12 Is work in progress as i am waiting for delivery from china, a 4'' handwheel for the right hand end of the leadscrew
Having used the vertical slide and for when turning without the compound slide we need fine graduated feed NOT THE RACK AND PINION
I decided to extend the leadscrew,fit ball bearings and a graduated handwheel dial. I wanted to replace the existing 20mm lg bearing block
with a new one 40mm lg with 2 bearings. Using a piece of MS 1/18" dia x 40mm lg i bored thru 17mm and opened both ends 21 dia x 5 deep to
Fit 2 new 12 i/d skate bearings This i welded to a piece of 50 x 8 flat 40lg.$ holes were drilled to suit the two existing and a third
drilled and tapped in the bed.The bottom RH corner of the brakt was removed to the contor of the bed.So i used 3- M6 fixings
I set up the brkt in the 4 jaw and took a 12 thou skim off the face of the brkt.This rduced the centre height to 22mm
I removed the existing brkt and replaced it with the new with the LH bearing fitted. I had previously drilled and tapped the end of the leadscrew M6 x 12 dp using a pistol drill. No real need to remove the leadscrew and use the lathe as the leadscrew was already centre drilled. I fitted a new 16od x 12id x 30lg spacer and then the 2nd bearing locking outer races with grub screws
I then turned a piece of 16 dia bar x 80 lg to 12 dia and bored thru 6.5 dia for the leadscrew extension. I the made a threaded stud
to bolt the extn to the leadscrew I am waiting for the delivery of the handle to finalize.I intend to make a graduated alum. dial locked with a thumbscrew and drill the extension to fit a threaded dowel to locate in the handle keyway. I have locked the extn to the leadscrew with a turned down WIZ nut with the thread left long for an
alum clamping nut Hopefully this will allow quick release of the handwheel as it will only be in situ when required. I will post
further comments when when the mod is complete Regards Barry

 

[bazmak]

PART 12 (Continued) Handle arrived from China. 100mm dia metal keywayed insert 3 spoke with revolving handle VERY NICE
$10 free postage HOW DO THEY DO IT.
Turned the lead screw extension down to 14 dia leaving a 2mm section at 16dia to shoulder against the bearing,14 dia for 16 lg to fit dial. then 12 dia x 16 lg to fit the handle. The handle had a 4w x 2 dp keyway. Drilled and tapped M3 at 90 o to the axis of the shaft.
Using an M3 cap screw i skimed the head to 4dia and faced to to 2mm high.,reduce the length and screw into the shaft. tweek a little
until its a nice sliding fit into the keyway.A simple way to for keyed fit without machining a keyway in the shaft
U sing 30 dia alum bored thru 14 dia and faced to 16 lg for a nice free fit on the shaft and recessed one end 16 dia x 2 deep
Setting up in the lathe and with a screw cutting tool on its side in the tool post,and using as a shaper with the rack and pinion
i produced the dial indicator lines and stamped as required.In this instance i just marked them out but near futur is to make a deviding plate the left hand ok the headstock. I drilled and tapped M4 and fitted a nylon plug and thumbscrew to lock the dial
Using the 30 dia alum i then made an locking collar to clamp the handwheel and trimmed off the excess M6 thread on the Leadscrew
extn. I also used the dial shaping method to knurl the outside of the locking collar (no knurling tool yet)
The whole set up works well.Handle can be taken off quickly by ndoing the collar and sliding off the key Dial and bearing works well
Although the leadscrew is disconnected from the chuck the gears are noisy and offer resistance Will look at disconnecting the gear train when i get to use it. The handle will be left off for normal lathe use...NEXT WHO KNOWS I am now running out of projects i might have to make something. Regards Barry

 

[bazmak]

Hi just learning how to upload photos.should be my new lathe and stand
with a couple of pieces of a chess set i made

 

[bazmak]

see the alum tray using gutter bolts to fix and fill tapped holes when tray not used
Xslide ext note th

e poker chip used as a locking collar as

Carriage clamp and new gibb plates

] Vertical slide with 63mm vice fitted

Lathe and bench as newly arrived

Support plate and eccentric clamping screws

 

[bazmak]

PART 13 is just details of the leadscrew mods.Everything has become disjointed as i have just learned how to upload photos
When gradating the dial i needed a deviding plt so rigged one up for now by marking out the headstock adaptor plt 60 equel divisions
and lightly popping then used an alum pointer taped to the headstock. The leadscrew i am sure is 16mm x 1.5 pitch so shaped
60 equel divisions. The end locking ring i cut 30 deep grooves to give a knurl/sline effect. Works well. I propose to centre drill the 60 pops and fit a brkt and detent screw from the headstock.Should be much more informative now i can add photos BAZMAK

 

[bazmak]

I seem to have lost some photos but have added descriptions on the images.Will repost all
so some might be repeated so bear with me.I am currently finishing the dividing head so will post with photos
when

co

i

de06.jpg[/IMG]mplete

BAZMAK

/albums/u664/bazmak47/XSlide01.jpg[/IMG]

albums/u664/bazmak47/Vslide05.jpg[/IMG]

 

[bazmak]

PART 14 When making the leadscrew mods i made a temporary dividing head to graduate the dial
and knurl the lock knob.It worked OK so i decided to finish it off.Its self explantory now i can upload photos
and add

] all for now folks

 

[bazmak]

PART 15 I wanted to reduce backlash in the apron gears and the rack/pinion.I emailed JOHN MORAN (gadget builder) who
kindly replied and gave me his thoughts.The logical way was an eccentric bush for the gear/gear mesh and to lower the rack
for the pinion mesh.I stripped the apron and rack and after taking multiple measurement decided that the gear/gear could move together 10 thou the bearing hole in the apron for the handle was quite good.The rack and pinion were really bad and needed to move together at least 20 thou.The rack was well made and straight/true but there wasnt enough meat and it would be difficult to slot the c,bored holes. so this was a non starter.Anyway the pinion was touching the top of the leadscrew cover so the answer was to raise the pinion.I CLEANED AND DEBURRED THE RACK BEFORE REFITTING I had dwelled on moving the pinion up

for a couple of days and one answer seemed to be to remove the 8mm stud,open out the hole in the apron and tap M10.Then make a new stud from 10 dia bar,eccentric turn the 8 mm dia and thread the other end M10.The new stud
could then be screwed into the apron and the eccentric positioned to adjust the gear centres and then locked with a nut outside the apron.A little involved and i wasnt happy it would all work.THEN CAME A SHINING LIGHT
As an afterthought i checked the stud for plumb/square with a steel rule.BINGO. The shaft was leaning away from the gear about 6 thou,a tap with a hammer fixed that.The shaft was leaning away from the rack by 10 thou over its lenght,3 or 4 harder taps
moved the stud past square by 10 thou towards the rack.I quickly reassembled everything.The gear/gear mesh has improved slightly
and the rack and pinion is almost perfect.If anything slightly stiff but i think this will ease with use
The moral of the story is try moving the stud before lowering the rack Regards Barry

 

[scruffy]

Hi Bazmak Ive just got the same machine and have found some great ideas from this thread> Thank you. I'll need to grab myself a decent piece of angle iron

 

[bazmak]

Hi Scruffy,thanks for contact keep in touch and let me know how you progress
Its a wonderful little machine when it is set up correctly

 

[scruffy]

Hi again bazmak, I have some questions for you.
How did you make the 40mm hole in the angle iron for your milling attachment? I have some big bits but I dont think they go quite that big.
Did you make that hole at the center height for the lathe? Did you use the tool post center pin to mount the clamp, or have you made new bolt on points for it?
Thank you in advance Scruffy

 

[bazmak]

Hi scruffy,have answered your questions thru email with attached photos
also found your thread and answered there.Also this post on my thread
Dont know whats best,but i find it easier to send photos via email
Please confirm you receive them.I will follow your thread with interest
Regards Barry

 

[bazmak]

Hi everybody,this is a modification of a mod.IE the vertical slide
Having just used the VS a couple of problems arose.Having done the mod to extend the cross slide travel
i realized that the VS was not on lathe CL when in mid cross slide travel.I also wanted to make it more rigid
The main problem was the 2 M6 screws picking up the stepped washer were insufficient.Being a cheapskate i decided
to extend the existing rather than make new.Obviosly anyone doing this mod from scratch would make
an extended bracket.The extended cross slide travel was nom 100mm and with CS in mid posn
decided i needed to move the Brkt approx 40mm the Photos show all.Havent used it yet will have to wait and see
regards barry

 

[bazmak]

I wasnt very happy with the cross slide.The existing cast iron gib was a joke;
Greatly undersize on all 3 dims and poorly finished.Almost 1mm undersize to
be taken up by the adjusting screws.When tightened the key twists and only
bears on 2 apposing corners. I decided to make a new one in brass,larger and
more accurate and FITTED.Also to add 2 additional adjusting screws
Question how to machine the 2 x 30o sides without a mill ??
I spent 4 hours making a clamping jig and doing varios mods to my belt linisher
Results were very pleasing and i easily got the new gib key to within 2 thou
Dimensions as shown
CROSS SLIDE DOVETAIL 155mm lg 6.6 AF high x 6.2mm AF wide
EXIST KEY 150mm lg 5.6m AF high x 5.6mm AF wide
NEW BRASS KEY 160mm lg 6.35h x 6.1 wide
Only about 5 thou now taken up by the screws
I drilled and tapped the cross slide for 2 additional screws and fitted/adjusted
the cross slide.Smooth as silk.BIG improvement,will look at the compound nexthttp://s1327.photobucket.com/user/bazmak47/media/GIB01_zps69d441d2.jpg.html?sort=3&o=2

 

[bazmak]

http://s1327.photobucket.com/user/bazmak47/media/GIB01_zps69d441d2.jpg.html?sort=3&o=2

 

[bazmak]

 

[bazmak]

Will post these mods here to keep the thread going.I was ready to start maching the flywheels for the horiz. twin but was worried about chatter caused by play in the carriage.
It was gradually getting worse so decided to strip down the lathe and resolve the issue.The gib plts were ok but the carriage could be rotated CW and ACW by riding up the V in the front bedway
Ther is no positive location front to back to the sides of the bed.In fact there was 60 thou clearance to the back and 20thou to the front.The location is achieved by the single V to the bed.Rotational force to the
saddlecaused lots of play when the carriage RODE UP the V
How to solve the problem.When i made the new brass gibb plts (see thread) i filed ,scraped and shimmed to suit.Now i had a mill,so removed the shims and skimmed down to a good fit. The front one had a 10 thou gap between it and the rack so i slotted the holes and pushed it up lightly to the rack before locking in position.I could not do this with the rear one as there was no machined face at the back only rough casting
I could fit a brass shim 60 thou thk and some screw to lightly press against the edge of the bed.But decided to consider this option at a later date.I had reoved 12 thou of shim and milled a 12 thou step in the gib plate and this shoulder i pushed up to the bed.Problem now appears to have been fixed.Only time will tell.If i Later fit the rear brass shim i might be able to cure another problem
When i first setup the lathe the cross slide when cutting was forming a concave end,being able to pivot the carriage a couple of thou on the gib plates may fix this problem
At the same time the plastic handle for the carriage was not ideal,in the pin.I made and fitted a brass bearing/spacer plate to the apron and a new cast cplate handwheel adjusted to a nice wobble free fit

 

[bazmak]

Never been happy with the carriage handwheel.Hope this latest mod solves my problems.As i mentioned previously i had broken the original 85mm dia handwheel.I tried a couple of 100mm chinese plastic handwheels and liked the one with the hinged revolving handle.However it wasnt rigid enough so fitted a 100mm cast iron handwheel.I had fitted a brass bearing plt to try take out the play in the handwheel shaft but still having problems getting rid of the end play
without overtightening.Decide to do a no of mods.
Recessed the brass plate and the handwheel and fitted an 8mm thrust brg
Made a fork and hinged the existing revolving handwheel.Previously the handle
had a slight clash with the cross slide handle which was annoying.Now its clear and i can hinge down the handle when taveling short distances by using the wheel.May need to tweek it further but the thrust race works we ll.

 

[bazmak]

Lots of little niggles with the lathe,lots of small mods that i wanted to do but kept putting off.Decided to get stuck in and do as many as i could all in one hit
Forget all other projects for a few hours.
First was the tailstock.Strap kept comoing loose on the accentric,handle was not long enough,clamp kept losening and swinging down.etc etc
Lengthened the handle slightly and fitted an alum. ball.Changed the short locking grubscrew for a long one and drilled and tapped for a capscrew stop.Now the handle stays in the operating range.Made a new heavy duty,fitted tee nut with a cap adjusting screw and a guide pin to stop it rotating.Everything now much improved. The strap on the eccentric was 3mm thk and kept coming off.#mm bearing area was elongating the hole.Silver soldered washers both sides to give a larger bearing area and stop the the strap coming off the eccentric