Messages

181

Tangent Corner / Re: Denford Orac problem

« on: August 23, 2006, 08:31:08 PM »

Hi David, Thanks for the info, I'm just waiting for the new chuck to

arrive and time to fit it. I made a plate to bring the toolchanger

up. I now have the drill positions correct and my insert tool needed

0.4mm packing. I guess this is right, I would have liked a bit more

space above the tool as sometimes I use tools made from HSS stock and

after a few regrinds especially with parting tools they'll end up

below center.

What's the largest radius insert you have used on the Orac.


Kind Regards
John

182

Tangent Corner / Re: Denford Orac problem

« on: August 20, 2006, 07:36:09 PM »

Hi Marcel, Thanks for that. I'll check it out tomorrow.



Kind Regards
John.

183

Tangent Corner / Re: Denford Orac problem

« on: August 20, 2006, 06:19:14 PM »

Hi Marcel, Thanks for that I guessed as much. Trouble is, When I bought the machine I was given the original single tool holder so I am guessing that the guy purchased the toolchanger and fitted it himself.

I shall try and get it sorted by a bit of trial and error until I find the right thickness for the spacer plate.

Kind Regards
John.

184

Tangent Corner / Re: Denford Orac problem

« on: August 20, 2006, 04:14:57 PM »

Hi Marcel, I do have a plan for the toolchanger, drawing number TP110. It has a spacer plate underneath the main body, item TP110/16. which is designated for the Orac and not the Easiturn 3.

It does not give any dimentions though. If I knew what the thickness of the plate was it would be helpful.

I have tried a 6mm plate but it doesn't give enough shim clearance for tools. I've tried a 5mm plate but still the same problem.

The thing I have noticed is that with a 6mm plate the tools were level, eg parallel with the bed. if I used a thinner spacer I will be getting back to sloping tools again.


Are your tools parallel or sloping upwards.

Kind Regards
John

185

Tangent Corner / Re: Denford Orac problem

« on: August 20, 2006, 02:45:14 PM »

Hi Tony, Yep, I use 0.4mm radius tip, Thanks for the suggestion though. I knew there was something not right with the machine when I put a HSS tool ground correctly (no radius) and tried that. Still had the heavy chattering. I removed the chuck and put a clarkson collet chuck in the spindle taper with a piece of 5/8 bar in it. No chatter what so ever. Guess it's the chuck then!

The main thing that threw me was the fact that the tools in the toolchanger are angled upwards towards the stock at about 3 degrees. Thinking that due to this, the tools will rub under the cutting edge, if set to the correct height so you can face to the middle of a bar the tool is not at a tangent to the centre if you know what I mean.

I have tried putting a plate under the toolchanger and adjusting the setscrew to get the tool height right and the tools level which is a fight between the drill tool center positions and the lathe tool positions.

I have found that in order to get the right positions and the tools level and the drill positions correct, I have run out of shimming clearance and all the tool positions are a bit low.

This has made me think that the toolchanger on the Orac is not designed specifically for the machine and is a bolt-on extra.
Not having any pics to look at I can only assume that the sloping tools situation is normal for this machine.

I must say that in using it, I have found no problem in cutting material.

A quick thanks for Marcel's info, I have checked for this and although the toolchange is dog slow, It stops solid on the ratchet with no play at all.

If anyone can give me more info on the toolchanger setup (or pics) I would be gratefull.

Kind Regards.
John

186

Tangent Corner / Re: Denford Orac problem

« on: August 18, 2006, 05:10:08 PM »

Hi Graham, Thanks for your info, After checking and double checking all possible things it could be you're right it's the chuck. It's one of those cheap Chinese one's and I tried yesterday to true the jaws up but I found they were soft jaws and I work with stainless steel alot so I have ordered a new one which is a TOS make and comes with a certificate. It's also supplied with hardened inside and outside jaws.

That should solve my problem and I can get back to normality again. 

Thanks again for your help.  



Kind Regards
John

187

Tangent Corner / Re: Denford Orac problem

« on: August 16, 2006, 07:27:03 AM »

Hi Graham, Thanks for your reply. My problem started when I recently bought the machine and fitted with insert tools. The toolchanger sits directly on the cross-slide and the tools are inclined upwards towards the chucked material at about 3 degrees. Having this chatter problem and thinking that the tool position is wrong I have made a spacer plate to raise the toolchanger so that the tools are level (90 degrees to the bed)

After doing this and setting the drill tool positions at exact center i find that my turning tools are now too low and there is no more adjustment. On this machine the tools are shimmed on top and the tool set screws are underneath the tools. Not quite a good idea in my book.

As this problem still persists I have ignored the settings for the drill tool positions and concentrated on getting the current insert tool correctly aligned.

It is level and at center height, well just a tad above just in case there is a bit of flex when cutting.

The finish when cutting is good although the side of the shoulder shows radial lines due to the chatter when turning into the shoulder.

I thought about your comments and this morning I went to check it out, pointing the tool as far as the set screw allowed to give a larger side clearance has produced helical pattern on the work and the side of the shoulder looks like a golf ball. Chatter still persists.

I must mention that the workpiece is 16mm dia and protruding 30mm out of the chuck.

I have cut longer stock with a center at the end and the chatter is alot less and at times none existent.

I have used the same tool on my Clarke hand-lathe with good results and no chatter so I'm still thinking there is something wrong with the Orac machine


Any ideas are welcome.

Kind Regards.

188

Tangent Corner / Denford Orac problem

« on: August 15, 2006, 03:39:33 PM »

Hi,  Is there anyone out there who uses a Denford Orac with a toolchanger fitted. I have a tool vibration (chatter) problem and all attempts to sort it have failed.

I've been a (hand) machinist for some years but being new to CnC causes it's own problems as well but all the different speeds and feeds i've tried fail to stop it.

I've checked head bearings, tightened gib screws, toolchanger bearings, tool height etc,,

I'm using a TPUN (triangle) type insert tool and when cutting down a shoulder on a bar, the tip cuts fine until it gets to the end of cut and sets in heavy chatter.

I've tried other insert tools and the same problem occurs.


If anyone would like to add their words of wisdom it would be gladly appreciated.


Many Thanks..

189

Mach3 and G-Rex / Re: Servo Dynamics

« on: August 03, 2006, 05:49:41 PM »

If you are into electronics What you will need is an 8 bit up/down counter connected to the step and direction outputs of mach3
and the same for your encoder then both 8bit outputs from the counters are fed to an 8 bit adder. This will give you the error signal in digital form. You will then need to convert the 8 bit error output from the adder to analouge with an A to D converter with an output offset to give the +10-10 command signal.

It might be worth having a chat with the guys at CNC4PC as they do some converter boards and I would have thought that a frontend for these old drivers would be ideal for a retrofit.


Regards
CJ

190

Works in progress / Re: Idea for Mach3/4 Jog screen

« on: July 09, 2006, 03:55:49 PM »

Hi, Nice one guys, That will make life alot easier. 

Many thanks.