Thanks Irving.
All sussed now,theres a little tensioning plate spring recessed in the shaft under the dial, a little bending of the tensioner plate and its gone a bit stiffer now.:clap:
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Thanks Irving.
All sussed now,theres a little tensioning plate spring recessed in the shaft under the dial, a little bending of the tensioner plate and its gone a bit stiffer now.:clap:
Lathe is allnice and clean now,but I want to swap over the chuck and spindle size to the larger size I have and use the smaller chuck possibly as a fourth axis?
Problem is I don't have a press to remove the bearings fom the stock casting,any ideas folks? short of buying a bearing puller?.
Go find a local gearbox repair place, they should have a suitable press.. and they can push the new ones in for you, keeping them properly square... bearing puller is fine for wheel hubs etc, but not for precision bearings...
When boring,does one maintain the same height as per outside turning ie center the tip of the tool for middle or just below middle of the workpiece?
Whiplash from overhaning rod sticking out the back end of the spindle,how do you overcome this?
yes you doQuote:
Originally Posted by GeorgeD
turn up a close fitting tapered sleeve the you insert in the end of the spindle.... for very long pieces an additional steady is needed (I used the fixed steady mounted on a lump of wood and clamped in my workmate)Quote:
Originally Posted by GeorgeD
Cheers,Irving.
I wasn't sure about using a sleeve loaded in the spindles rear,I'll cut a bit of broom handle off her indoors broom,she won't fly around as fast then. lol
:wink:
Whats the stronger material Delrin or Nylon? going to purchase some on ebay to account for this type of scenario.
all depends on what you plan to do...delrin is harder wearing and the better engineering plastic generally, Nylon is cheaper... Nylon is good for rollers and stuff where friction is low but there's not much sliding movement... delrin is the better choice for things such as leadscrew nuts where there is a trade off between friction and wear...Quote:
Originally Posted by GeorgeD
Its only for the rear spindle inserts for a couple of different sized longish bars to stop the whiplash.
Just turned this threaded rod down from 12mm to 10mm for the bearing,chuffed I am... don't want to push it on all the way just yet as the end bit needs a screwthread on it tolockthe bearing in place,mind you it doesn't really need it as the bearing is a tight fit.
Forgotto say,this is stainless steel.
Will have to make a guard for over the apron wheel...or its a case of ow,ow...ow...ow
due to little hot pieces of metal hitting me hand. lol
wimp...................................
Seems to me George you need to practice some more on other materials and learn something about feed rates, depth of cut and surface finish... that shaft shouldn't be scored like that, it should near mirror finish like the outside of the bearing...... I hope you weren't using the apron wheel to traverse the cut and were using either the topslide or, better still , the powered feed...Quote:
Originally Posted by GeorgeD
What part of the shaft are we talking here,Irving? if its the part where the bearing is seated then thats the threaded part ie I can't turn down anymore as the bearings bore is 10mm and as it stands now is perfect fit with a thou difference to accomodate forcing the bearing on.
If its the end part? then it doesn't matter as I stated it will be threaded for a locking nut
What size tooling is the norm for these mini lathes? fed up trying to get the dead center height...the 3/8 are nearest but the height is marginally over center.:mad:
Thats why you need a QCTP, its easy to set the height... and 8mm is the norm and then shim it... 3/8" is 10mm and is marginally too big unless you use a QCTP...
Hi Irving.
I'll be using 10mm shank tools from wendsday.took it into a local machine shop to have 3thou taken off the sole of the toolpost...he's only charging me a tenner. :dance:
Don't forget the the tip location varies from tool to tool... even if you skim the footplate (which is what I did on my larger lathe so i could use modern 16mm cutters instead of 5/8"), you will still have to shim on a tool by tool basis. Thats why a QCTP is such a time saver.. one clamp block per tool and then you can swap them around without resetting the height.
Well,when one of my bets comes in I'll continue to suffer to change bits,until then monitary funds are low...well at least thats what she says. :whistling:
My first serious piece on the mini lathe...the rail mounts,this is only one...need 3 more for the bed.
Not too bad methinks,bore diameter is spot on...only need to drill four equal holes around the shoulder. :dance:
Attachment 2679Attachment 2680Attachment 2681http://www.mycncuk.com/forums/images/misc/pencil.png
Hi George,
If you have enough material on the flange, you could drill the hole spacing to match commercial clamps (shown below), leaving yourself the option of upgrading if these plastic ones are not stiff enough.
How do RCNC,
Below is a pic of how they will be mounted, the bed will be 60mmx25mmx3mm wall,mild steel box section.
The flange will fit through a 25mm hole in the 60mm wide part of the box section and the shoulder will either be held in place by 4x nut&bolts or self tapping screws? the little red boxes are 2x grub screws and the rail counter sunk to accept those grubs.
Attachment 2683
Need to pick your brains,Irving
I'm not getting a good face cut on the ends of steel,its all rough banding.
The tool is dead center height...I have a feeling the saddle is moving as I try face cut the rod?
what tool, how far out from chuck, what diameter rod, what spindle speed... and did you lock the saddle to the leadscrew?
The tool is about 20mm out of the toolpost and is slightly angled to the face of 16mm stainless steel rod.
Speed? well can't give you exact speed in RPM but the dial is pointing at 10 o'clock position I'd say about 400 to 500 RPM?
No didn't lock the saddle up :redface:
Sorry about the noise on the pics,seems I pic noise up in the camera when using standard batteries and its ok when I use rechargable...most odd?
Attachment 2812Attachment 2811http://www.mycncuk.com/forums/images/misc/pencil.png
well locking the saddle to the leadscrew is a must, tho a proper saddle lock is better (nice little weekend project to make and fit - works similar to the tailstock camlock... unless of course you've not made one of those yet). Most of your problem there is probably that, tho movement of the cross-slide on its gib might also be a factor if the gibs aren't properly adjusted.
You need somewhere between 600 and 800rpm for that diameter/material, its actually 560 at the outer edge but increasing rpm as you go in, so 1120 at the 10mm mark, so take an average as you can't easily change spindle speed on the fly.
With stainless you need to be taking a very light cut and use lots of coolant and a newly sharpened tool. I can't easily tell from the pic as the tool tip is out of focus but it doesnt look too healthy.
Hi Irving
Light cuts ya say? anything thicker than a piece of paper and I sh*t me pants. :eek::wink:
Hi Irving
Been watching a few vids on youtube about face cutting,noticed a couple of guys using a tool going across the face with the toolpost directly in front of the piece and they used the same technique for side turning.
Is that the norm or should I just use a face tool and go into the piece with the flat of the tool.
here's the vid....
http://www.youtube.com/watch?v=yaoMP...eature=related
thats the technique I use. tbh it doesnt matter where the toolpost is, but you should always go for the shortest overhang of the tool, so running it square gives you that. You will notice in the video that there is still a rake on the tool, its not flat to the work, there is a nose that cuts and it'll have been honed slightly round to get a good finish... As a general rule I keep my toolpost square to the work and ensure the tool tip is correctly angled on all sides, but then I use HSS tools not premanufactured carbide ones.
I was thinking of grinding my own tools ie just the facing,turning and parting off ones,the boring ones I have bought in the index replacable tip type.
Would these be suitable,Irving....
http://www.rdgtools.co.uk/acatalog/S...d_prices_.html
Just a thought - what are you using to shim the tool - it needs to be something uncompressible like steel strip - hard to tell what it is in the picture.Quote:
Originally Posted by GeorgeD
If you can't get it exactly to hight, err on the low side rather than the high.
How do FF.
Its a thin piece of card,but to be honest I didn't think that would be the problem as I picked some tin can up yesterday for shimming and its the results are the same.
I'll get some new tooling this week and see how I fair from there,just could be the nature of the beast ie hardened stainless steel?after all these machines lack a bit of oomph in the torque/power,I mean 300watt motor...c'mon:lol:.
No problem with ally or delrin.
:beer:
Yes I'd imagine so, tho I bought a few ready ground but then adjusted to my own preferences and I already had a load of bits of 1/4" and 5/16" tool steel that came with the various old lathes I have acquiredQuote:
Originally Posted by GeorgeD
The key to getting a good finish is stopping the tool deflecting while cutting, there are several ways to ensure this...
All components between the tool tip and the workpiece must be rigid, not rigid as cant move them with your fingers but rigid as in cant move them with a crowbar! Card is a complete no no, even tin can shim needs to be flat, clean with at most three layers and the tool needs to be well clamped down.
Keep cutting forces to a minimum - deflection is proportional to force. Make sure the tool tip is very sharp - use a high power magnifying glass to examine it and sharpen if it looks at all rough or rounded. It can help to put quite a lot of top rake on for finishing but this tends to make the edge fragile so you have to be careful. You can also use a more pointy tool (technical term) but you then need a finer feed.
Depth of cut, depending on the material, a cut the thickness of paper (0.1mm) might be considered a fairly heavy finishing cut ;-)
Coolant will help protect the tool tip and keep it sharp, if you don't want to use a stream of coolant then the Rocol stuff is pretty good.
The replaceable tip tools tend to be relatively blunt as they're designed for production use on heavy duty machines. It's possible to get sharp ones but carbide is prone to chipping so they are fragile (if you stall the lathe and then rotate the workpiece backwards to free it off, you'll more than likely chip a carbide tool) so I'd recommend HSS tools for a lathe this size.
HTH
Mark
Hi Irving
I'm struggling here on the Lathe,basically I'm having trouble parting-off...the lathe judders and for the life of me can't understand why I'ts proving difficult to part-off?
Last nightI set the gibs as they were a bit loose,today I got some new tooling and blanks,I've tried parting-off at different speeds,the tool is marginally belowthe center...I used the live center to set the tool up.
Stainless Steel bar,had to cut the workpiece of with a grinder :lol:..it ain't funny:cry:
Any pointers as to whats wrong?
Problem solved,it would seem these Lathes struggle to part-off on hard material and the only remedy is a roller bearing change for the naff standard ball bearings
that come standard. :mad:
Now I will have to change em,thank god I don't have to turn a bit off the larger spacer on the spindle because this model doesn't have it,only the thinner plastic spacers which are easily grinded down on a table grinder.
Forgot to mention,whilst scouring the net for info on these lathes I happen to think up an idea for DRO's on the cross-slide and compound but how to fit them?
In Lidl they had those cheap digital calipers which work on the same basis as the DRO's plus they readout inches and mm...so Lidl here I come.. :whistling:
I suppose given a little lateral thinking these couldalso be adapted to other machinery?
This will do nicely sir. :naughty:knowing my luck theywill have none left.