Rough Finish

[rcfreak177]

I Have a SX3, great machine in its manual form, mine is now cnc and is even better. I have never owned or used an X2. I will not harp on about the manual X3 or SX3 as I only used it half a dozen times before the conversion.

There is another guy on this forum (rodw) Rod also bought a SX3 a while back and had some good things to say about the machine.
Here is his thread in regards to his gear.
http://www.homemodelenginemachinist.com/f15/rods-aussie-shed-19885/

Rod is also a great guy to chat with, (lives not that far from you near Brisbane) I am sure he will rate the machine in manual form for you.

This goes without saying but having a shop with both a mill and lathe makes thing so much easier, also opens up broader horizons for potential projects.

I say if the funds are there go for it, you won't regret it.

Baz.

 

[Philipintexas]

PYROBREWER: Now that you have us all wondering, how did you hold the material as shown in your original post??

 

[goldstar31]

Experience dictates that the tool was not at correct height. There is signs of is or what was a pip. I would have thought that it would have instantly brought a correction of tool height. After all, that is about the only useful thing that QC tool things possess( in my opinion).

OK, I have had my say but there are others who are now writing on Madmodder about -how to grind a suitable tool- without a jig.

Not my way of doing things but seemingly a vast improvement to what has happened. Certainly worth a look.

What is also 'worth a look' is the excellent series of suggestions by a Mr John Moran in his Gadgetbuilder website. He constructed a jig to Martin Cleeve's design-- and I made one up. Again, he describes several tool and cutter grinders and offers his opinion. Now, I have a Quorn, I have a Brookes or more correctly, the improved version as a Stent and a Kennet and a Clarkson. He describes a Tinker which is something that one makes in a easy week and out of lumps of metal. Actually I have the plans but making one is rather overkill but the principles are excellent.

Whatever your views and experience, Mr Moran has certainly provided a lot of clever machinery.

 

[pyrobrewer]

PYROBREWER: Now that you have us all wondering, how did you hold the material as shown in your original post??

This is the only photo I have of the setup as it was - 4 jaw chuck jaws gripping 2 on each long axis. There is a video that also shows nothing. I had to move the plastic safety cover over by one screw hole to avoid it tapping on the job. It was in tight as I was worried about it flinging around the room!

Am I being unduly cautious about this?

What speed would a "pro" spin this at?

Tool Bit was checked against centre in tailstock and passed through the centre of the job without noticeable tit. The were some regions of smooth running (in the bad section) so I checked the Tool for tightness, post was secure as well as slide gibs all tight. Carriage was locked down using the built in carriage lock which I have found to be not very good or at least I am not very good at using it - this may be more likely. I had to fix it once as it had fallen of the tightening screw! It is just a small tab that simply grips the bottom of the bed.

However! on closer inspection with 10 power loupe a chip had broken off of the indexing tip. It was my last and am waiting for new tips from hare and forbes.

https://www.machineryhouse.com.au/L005A

Are these available somewhere separately as i will soon have an excess of threading tips!

http://www.homemodelenginemachinist.com/attachment.php?attachmentid=65282&stc=1&d=1382433783

 

[goldstar31]

If you are running out of tips, you should ask yourself why.

Carbide is not a very forgiving material and the least mistake of whatever sort will break the tip.

Last evening I had 5 minutes to myself and went into the workshop after a long absence- to see what damage from damp and see whether I had given the wrong information. I grabbed the first spare tool- a wrong chamfering tool, stuck it in my little grinder and cut a facet holding it in my fingers. All went well and then I lost the cutting edge. In my haste, I'd forgotten to tighten the tool holder down. OK, I put the edge back on the tool in seconds but this was hss. I'd lost a few minutes and at no other cost to myself. Even then the finish with a loose tool was far superior to yours.

The moral is obvious.

 

[pyrobrewer]

If you are running out of tips, you should ask yourself why.

Carbide is not a very forgiving material and the least mistake of whatever sort will break the tip.

Last evening I had 5 minutes to myself and went into the workshop after a long absence- to see what damage from damp and see whether I had given the wrong information. I grabbed the first spare tool- a wrong chamfering tool, stuck it in my little grinder and cut a facet holding it in my fingers. All went well and then I lost the cutting edge. In my haste, I'd forgotten to tighten the tool holder down. OK, I put the edge back on the tool in seconds but this was hss. I'd lost a few minutes and at no other cost to myself. Even then the finish with a loose tool was far superior to yours.

The moral is obvious.

I've run out of tips because I have never bought any! The tips I had came with the machine, my first.

I am glad you were able to produce a better result than my FIRST attempt at this procedure.

I am sure that I have made many schoolboy/apprentice mistakes with the 5 or 6 pieces I have chucked up so far. And no doubt will make many many more, as I am happily at the start of what I hope to be a long, steep learning curve.

Also, as a complete newb, unfortunately you will need to explain the "obvious moral"

 

[goldstar31]

The moral or morals might be summarised as
1. a correct set up
I admitted what I did wrong.
2. then there was the question of being able to 'soldier on' regardless of being stuck for tooling. I'd chosen high speed steel bits but I could have rummaged for an old allen key or a cycle spoke or a bit of a cracked ball race- to mention three equally unusual but more than possible tools.

I must emphasise that I did refer you to tooling and techniques which were adopted by other workers- rather than myself. I was at pains not to suggest that my approach is not the only way of doing things.

I can only apologise if this has caused offence to you.

 

[pyrobrewer]

Thanks you have given me an idea to make a flat faceplate that I can glue sheets of abrasive paper onto. You are correct about the lack of large equipment, I have a bench fully set up for Jewellery work (on of my trades) I have to get used to scale up from MM to inches

Mill is on the wish list.

The likely causes have been mentioned several times so will not beat on that.

This is one time where a fly cutter on a mill will do a better job than a lathe.
IMHO having it surface ground while will solve the problem is overkill and counter intuitive the point here is home shop machining.
I am guessing you do not have a mill or a large enough one for this piece.
Personally I would take the item to the belt sander and smooth down the ridges.
But you may not have a belt sander with metal cutting belt. so silicon carbide paper and oil should smooth out the ridges . A little flat filing to start may speed things up.
Tool makers and die repairmen have used files and abrasives for years to smooth and correct a lot worse. Your shop your dime you are the QC guy that needs to be made happy.
Tin

 

[pyrobrewer]

I Have a SX3, great machine in its manual form, mine is now cnc and is even better. I have never owned or used an X2. I will not harp on about the manual X3 or SX3 as I only used it half a dozen times before the conversion.

There is another guy on this forum (rodw) Rod also bought a SX3 a while back and had some good things to say about the machine.
Here is his thread in regards to his gear.
http://www.homemodelenginemachinist.com/f15/rods-aussie-shed-19885/

Rod is also a great guy to chat with, (lives not that far from you near Brisbane) I am sure he will rate the machine in manual form for you.

This goes without saying but having a shop with both a mill and lathe makes thing so much easier, also opens up broader horizons for potential projects.

I say if the funds are there go for it, you won't regret it.

Baz.

Cheers mate

I have done some correspondence with Stuart From Titan about mills. My initial enquiry was about http://www.ebay.com.au/itm/200976330837

I then asked about the SX3 and he suggested the TM25v
http://www.ebay.com.au/itm/200977847587 it is the same as the one listed but with a belt drive.

[ame="http://www.youtube.com/watch?v=m_T9EiLIU6U"]http://www.youtube.com/watch?v=m_T9EiLIU6U[/ame]

I just got out of hospital (gall bladder removal) and have a sympathy card to play against the financial controller, but I am not sure it will stretch double for the TM25v no matter how much better it is! Maybe I could have something else removed! And after buying the lathe she is aware of the "accessories" which can double the price again.

Rod would be 3 1/2 hours south of me if he is in Brizzy
Cheers
Mick

 

[Tin Falcon]

I think the biggest lesson learned hear Is.......................
Carbide loves speed. But ........ is sensitive to shock pounding and easily damaged by intermittent cuts.

Usually when things go south it is because we forgot to follow the basics.

so what are the basics ?

1) work held securely I think you did that.
2) tool
a) correct tool for the job would have been a good grade of HSS with cobalt.
b) held securely minimum stick out
c) correct height

Speed rpm of the lathe calculate based on material and diameter of the material and tool material. Use chart or clulator such as

http://littlemachineshop.com/Reference/CuttingSpeeds.php

feed how much the tool is avanded per revolution.

lube coolant sulpherized oil or water suluable oil for steel
hope this helps.
Tin

 

[pyrobrewer]

I think the biggest lesson learned hear Is.......................
Carbide loves speed. But ........ is sensitive to shock pounding and easily damaged by intermittent cuts.

Usually when things go south it is because we forgot to follow the basics.

so what are the basics ?

1) work held securely I think you did that.
2) tool
a) correct tool for the job would have been a good grade of HSS with cobalt.
b) held securely minimum stick out
c) correct height

Speed rpm of the lathe calculate based on material and diameter of the material and tool material. Use chart or clulator such as

http://littlemachineshop.com/Reference/CuttingSpeeds.php

feed how much the tool is avanded per revolution.

lube coolant sulpherized oil or water suluable oil for steel
hope this helps.
Tin

Thanks Tin
Much better post than "mine is better than yours", or "you did it wrong" type posts
I know I did it wrong/poorly thats why I asked the question...
Cheers
PS Had a good laugh when i worked out what avanding the tool was!

 

[Philjoe5]

I would only add one item to Tin's list.

Every cutting operation on the lathe puts a force on the cutting edge of the tool. Even a relatively rigid set up on our hobby lathes will result in enough force on the cutting edge to flex the tool and give a rough finish. So what to do? When you're near to the size you want to machine to, reduce the cut depth and you'll reduce tool flex and improve finish. On my 350 lb lathe, a finishing cut is rarely more that 0.002" - 0.003", often less than that.

Cheers,
Phil

 

[pyrobrewer]

SWIFTY: Yes, I realize alum. is different, just saying I think this is a problem of lack of rigidity in the work as opposed to the cutting speed. As I said, I've cut to the center of junk steel at slow speed and never experienced this kind of finish.
I think the poster wants an answer to his particular problem not suggestions of different methods that might be better.
Given what he's trying to do, I think it can be done with decent results if there is adequate rigidity in the work piece and tool.

I just did a trial cut similar to the one originally posted. 2" X 4.5" X 3/8" thick hot-rolled steel (?) in a 4-jaw chuck, light cut (.025) with a HHS tool @ 425 RPM and a slow feed, no lubricant. My results are, the finish improves toward the center of rotation. As expected, the interrupted cut is slightly rough and finish improves when the cut is continuous even though it is painfully slow surface speed near the center.

To address the original question, Even though it's not necessarily the best tool for his job, what caused his finish to go to pot?

My, what a big chuck you have! It wouldn't swing on my lathe!

 

[pyrobrewer]

SWIFTY:
I just did a trial cut similar to the one originally posted. 2" X 4.5" X 3/8" thick hot-rolled steel (?) in a 4-jaw chuck, light cut (.025) with a HHS tool @ 425 RPM and a slow feed, no lubricant. My results are, the finish improves toward the center of rotation. As expected, the interrupted cut is slightly rough and finish improves when the cut is continuous even though it is painfully slow surface speed near the center.

I have not yet seen a tool mounted the way yours is. It must be very easy to grind that tool as it appears to have just one facet?

 

[Philipintexas]

It's my go-to tool for almost everything. It's called a "Diamond tool holder" and comes from your country. One quarter-inch tool will last a life-time and it's easy & quick to sharpen. www.eccentricengineering.com.au

 

[Forestgnome]

Personally I've had more problems with carbide during facing operations than any other cut. Sometimes I'll get a little flex right at the tit and off goes a chip on the carbide. I use HSS unless I'm cutting cast iron or hardened material.

 

[pyrobrewer]

It's my go-to tool for almost everything. It's called a "Diamond tool holder" and comes from your country. One quarter-inch tool will last a life-time and it's easy & quick to sharpen. www.eccentricengineering.com.au

You have sold me on it (and their website) I have ordered the 9.5mm L&R option pack and an extra bit!

 

[Tin Falcon]

The Other basic I should have mentioned if set the tool to prevent dig in. Like phil said there is a tendency for the tool /machine /setup to flex when force is applied.
My first list mentioned steps to minimize the flex. But one must also remember to position tool in such a way as when the tool flexes it moves away from the part when more force than it likes is applied.
So how does one do this ?
Facing think of the tool perpendicular to the part. Slightly toward you is OK but the tip away from you may case dig in.

Turing tool on center or slightly BELOW .
boring slightly ABOVE center.
Tin

 

[goldstar31]

I appear to be getting swept up by other people's opinions. Whether they are right or wrong or argue which is better or worse but my way to tackle a long job rather than the turning in the face plate of 'my' bit of square stuff is to sweep face using the faceplate or catchplate ( or even the 4 jaw at a push) holding the work on the saddle.

Within the limitations of something like a 918/920( I had one), I also had- probably have a gimcrack bit of round with three positions to hold a short length of hss tooling and for it to have a No2 Morse taper to hold it in the spindle. Now this is how the people who wrote the books and did all the designs that people today are making or copying or improving went about their business. It was not until about 1973 that the first real milling machines became available for the likes of them and me.

I made up a Ned Westbury mill from home made aero chocolate castings from the local college.- I know. The little sweep face effort was Martin Cleeve who never had a mill of anysort.

My contribution for today. People can argue, disagree or do whatever they deem appropriate but that is what done-- and it worked.