TAILSTOCK CAMLOCK
(aug to dec 2006)
JOB SUPER DONE , MAN
now I can start to work on single parts and asembe them togheter.
The sieg tailstock locking system is really shit! The locking base (yellow bit is not flat side to side as the picture shows )... (left end is higher that right end ..)
this causes the clamp bit to (jam) hangs up on the lathe underrails sides every time I try to move the tailstock left or right.
Many times the yellow block is stuck in between the rails with a strange angle that require the complete separation of tailstock/bolt/clamp to solve the problem
Why this system is so bad made!!????
I am sure that all the sieg lathe (and many more brands) holders are not happy about the tailstock locking system ...
I don't care, I will transform this piece of shit in a nice, precise and smooth tailstock with a superfast cam-lock locking syetem (lever)
as always the tech drawing are the source from any job!! check this
yes, I know I have done too many drawings, but this project require lot of thinking!!
The projects starts machining down the yellow clamp sides until a perfect clamping surface is achieved.
after that I had a look on the other side and it was also really shit (not flat)... so I started to machine it in same way of the clamping sides to make a nice true flat and squared surface, ready to be machined with a new clamping bolt/base
...the hole received the same machining....
..to make a new locking bolt I started from a 25 * 8 mm steel rod, machining it down to fit perfectly the yellow block slot, 4 sides of the steel rod were made true flat.
and then were cut..
to finish the bit two more sides required a flattening action.
the tail stock is placed on the mill table to get the 15mm drill, the original 13.00 is too small to get a precise and smooth locking system (draw bar)
to be sure that the 15mm drill hole is made vertically I check with the DTI the position of the bottom of the tailstock.
right, the drill is made and as expected the drill size is 15.05mm.
now it is turn to calculate where to drill the horizontal camlock sitting. 5mm lower that the edge in my case..
drilling firs with a 9.5 mm drill bit, down for 58,00 mm
and then to get a precise 10.00 mm sitting, I have to finish it with the dormer end mill 10.00mm
with previous step the machining on the tailstock is done. now it is turn to make the two important bits, which are
1) camlock (horizzontal camlock)
2) draw bar (vertical clamping bar)
on the lathe I turned from a 16.00 mm stainless steel rod bar the camlock system.
Initially I turned down the internal side as required (9,96mm) and then the outer 18mm, at 15.98.
the camlock is made moving in offset the bit and releasing the tailsotck center.
the offset made is 0.75mm, that give me 1.50 difference of diameter on the camlock.
The camlock is 9.96 and the smaller diameter is 8.50.
This step can't be made with a 3 jaws chuck. an independent 4 jas chuck is what is needed to makes camlocks.
for helping newbies, I stick here the table I have created in the backplate page,
chuck comparison:
photo shows the camlock after the machining.
for the draw bar , I started from the rest of 16.00 mm stainless steel rod.
a nice finish on the 14.98 mm is what I need to have no play between the sitting (tailstock body) and the drawbar itself.
the picture shows the drilling of M8 hole... the external 35mm long M14 thread is done, as well the 14.98 finishing on the left side...
this picture shows the threading of internal M8. I use dormer taps. Do not forget tapping fluid that makes things easier.
right, the parts are made now. (as you note the camlock has lost the M12 two pitch thread, this is because I saw that it maintain the position without the thread, so I decided to remove the pitches..)
the draw bar is mounted on the clamp
bottom view. note the perfect rectangular bit that allow the draw bar to move right or left following the movements of the tailstock.
you know that the tailstock must be trimmed or can be moved offset to make conical parts. this is why the draw bar must be free to move right and left, but it must keep the compound strong and fixed.
what is wrong in the original sieg clamp/draw bar system is that that draw bar (the bolt) is free to move, so when the user want to slid the tailstock the clamp moves to going out from the vertical and that makes the clamp to jam onto the lathe bedways. the only way to unjam it is to loose the tailstock bolt two pitches more, .. wo wowooo a long thins that made me nervous lot of times!
with the rigidity of the new compound(clamp/draw bar) combined with a precise draw bar sitting in the tailstock body, is practically impossible to have jams onto the lathe bedrails.
next photo show HOW the camlock pulls up the draw bar. (the photo shows the "loose" position of the draw bar)
right, the two parts are mounted together... (I used an old lever I had to make the tests, then I will make the proper long one with a ball on top)
parts are arrived from ebay....two 12" long 12.00 mm steel rods...
10 minutes on the mill and the ball (pool keyring) is ready with an M10 Thread and a 10mm x1 slot .
I am machining one bit with an M12 thread (bottom side), and then M10 on the other side (ball side).
The handle is ready to, as showed.. now it is time to assemble the lever on the tailstock.
voilà, the handle is mounted...
a close up to the camlocck/lever (all stainless steel) and the lever stopping system (an M8 bolt with some thermal plastic around!)
tailstock mounted on the lathe: left unlocked, right locked
and a MONSTER view.
right, the project is finished and now I am playing with the tailstock moving it left and right each 4 seconds.
I am like a kid with a new toy!! Trust me that the tailstock camlock lever is really one of the first things to modify on a new lathe. It is so nice to feel the tailstock free to move and then "zap" locked only moving a lever! the times when wrenches and bolts were on the tailstock are gone!!
forever!!
