B
Bogstandard
Guest
I am not doing a full runthru of engine turning (ET) because a lot has been talked about it before, so I am doing an abridged version of what I use, and how I do it. There are lots of different ways to carry out engine turning, my way is the one I prefer.
These have been mentioned before, but to save you searching, I have included them again. The first one Is Eamon Keoghs page, and it shows how a professional makes his items look. He is very approachable and gave me a few very good tips.
http://www.cs.ucr.edu/~eamonn/et/et.htm
This is a company that makes flat sheet engine turned panels, I would imagine using CNC for the patterns. I have sent you directly to the display page, and if you click on the little pics, they open up to show how the pattern is produced.
http://www.fpmmetals.com/Architectural.htm
Now my way of doing things. First off, where the ET is not being done, I polish the parts of the job to a finished state. ET will cover up slight scratches on a surface, but don't expect it to cover up the scratches if you have been using the plate as a rollerboard, without the wheels.
These are my tools of the trade, there are many others that can be used, anything within your imagination, as long as it is legal. The rules are, something spinning with a flat end, something that can go between the spinning flat end and the job, that can scratch the plate surface, and when it is all brought together, engine turning ensues.
The white mounted bobs are my main preference. It comprises of a hard rubber compound with an embedded abrasive. You can buy the same sort of material under the name of 'Cratex'. The other two bits show items that I have used in the past, aluminium and delrin rod, but again almost anything will do, but it does need to be a softish material, wooden dowel is a good one. Apply the abrasive to the end of the rod, and your are away, recharge the tip when it needs it, or for a real messy job, cover the whole surface in the abrasive and just go for it. I use the full cover method when I want a very fine finish, and so liquid metal polish is used.
So from now on, I will be showing me using my favourite bits, and if you do try 'Cratex' the following few paras will be of interest. For our Imperial cousins, all measurements now will be in yards, furlongs and miles.
If you are going to do accurate ET then you need to set yourself an easy standard to work to, otherwise, within a few passes you WILL be that confused you WILL make a b***s of it.
I will be working on a 0.500" (1/2") baseline, if you work in metric I would suggest something like 10mm or 20mm. You need an easy figure to divide into half.
You can see on this pic, my 'scratcher' is a little larger than it needs to be, it could be used as is, but some of the effect would be lost.
Normally I would spin the bit against a grinding wheel dressing stone to get it to size, but in this case, because I couldn't find my one, I used a bit of looped rough emery. It did the job, but it was a lot slower. On no account do it against a file, it will remove the file teeth without a pause for thought.
Now we got size (or near enough it doesn't matter).
If you looked at the last link that I posted, it should give you some idea of the effect you require. Most people go for the standard fishscale effect, starting at one side or end and work your way across or down. Being an awkward a**ehole, I like to do my favourite one, that is starting in the middle and by swapping from side to side, eventually get to the outer edge. I prefer this one as it gives a more even holographic effect than the fishscale one, when viewed from certain angles.
This is where my little book comes in, I find the centre of the plate, and draw up a diagram of the pattern and offsets. Doing it this way, I can always refer back for my offsets and put my mind straight again. A quick calculation and I am back on course.
'Scratcher' centred up on the job, and aligned with the end of the plate.
Notice how close it is set to the plate, about 0.100"(1/10"). This allows the handle to be moved down with a couple of fingers pressure. I do a constant count that is dependent on a test scratch on a similar piece of material. I found on this plate, down with slight pressure on the plate, count to four, release. That will be constant throughout the whole exercise.
Zero, zero, and that is my datum set up for the whole job. Everything from now on works from that point. The Y will always be a multiple of 0.250"(1/4"), the start of each alternate row will be either a full half inch number or a quarter inch number, followed by half inch spacing. I start at the same end for each row, but you could just put in your sideways and endways offset, and go back up the row. But you must remember that each row either side of centre, should be started at the same end as the opposite one the other side of centre. Confusing isn't it? Now you see why I am totally brain dead.
This is the first run from datum to the other end with a 1/2" pitch.
Before going further, I will explain about lubrication, if you are using this dry stick method. Without lubrication, the stick will quickly burn out and erode away.
Eamon Keogh suggested to use WD40 as a lubricant, rather expensive if bought in the spray cans, and on this job I have used it for convenience. Normally I would make my own lubricant out of either white spirits or paraffin, with a dash of 3 in 1 oil, shaken not stirred. I usually paint a stripe of it down the line run and just go for it.
So using my pattern, wind back to the datum start.
Then put my offset in for the next run. The third run will be on the opposite side of centre and so on.
I had had enough by the time I got this far and couldn't concentrate any more, about two hours accurate work. I am lucky in that when I turn my machine off, the DRO remembers where it was, so I could pick up the job again anytime, as long as the plate wasn't moved out of the vice. If yours won't allow you to do that, or you are handballing it with the dials, you have two choices. Either carry on and finish it, or stop when you reach a known datum, and write it down, then restart on the known datum of where you stopped.
This pic looks like a crap finish, engine turning never looks right in a straight on light.
This is what it looks like in oblique lighting, and shows the normal effect the eye would see.
There are very many ways of doing ET, from handballing with an electric drill, thru running down the edge of a ruler under a drill press chuck, to what I am doing here. None are wrong, if the effect suits yourself, it is correct.
Give it a quickie go, you just might impress yourself.
I will finish this job off when I can get back to it, and show you the finished result on my next post.
Bogs
These have been mentioned before, but to save you searching, I have included them again. The first one Is Eamon Keoghs page, and it shows how a professional makes his items look. He is very approachable and gave me a few very good tips.
http://www.cs.ucr.edu/~eamonn/et/et.htm
This is a company that makes flat sheet engine turned panels, I would imagine using CNC for the patterns. I have sent you directly to the display page, and if you click on the little pics, they open up to show how the pattern is produced.
http://www.fpmmetals.com/Architectural.htm
Now my way of doing things. First off, where the ET is not being done, I polish the parts of the job to a finished state. ET will cover up slight scratches on a surface, but don't expect it to cover up the scratches if you have been using the plate as a rollerboard, without the wheels.
These are my tools of the trade, there are many others that can be used, anything within your imagination, as long as it is legal. The rules are, something spinning with a flat end, something that can go between the spinning flat end and the job, that can scratch the plate surface, and when it is all brought together, engine turning ensues.
The white mounted bobs are my main preference. It comprises of a hard rubber compound with an embedded abrasive. You can buy the same sort of material under the name of 'Cratex'. The other two bits show items that I have used in the past, aluminium and delrin rod, but again almost anything will do, but it does need to be a softish material, wooden dowel is a good one. Apply the abrasive to the end of the rod, and your are away, recharge the tip when it needs it, or for a real messy job, cover the whole surface in the abrasive and just go for it. I use the full cover method when I want a very fine finish, and so liquid metal polish is used.
So from now on, I will be showing me using my favourite bits, and if you do try 'Cratex' the following few paras will be of interest. For our Imperial cousins, all measurements now will be in yards, furlongs and miles.
If you are going to do accurate ET then you need to set yourself an easy standard to work to, otherwise, within a few passes you WILL be that confused you WILL make a b***s of it.
I will be working on a 0.500" (1/2") baseline, if you work in metric I would suggest something like 10mm or 20mm. You need an easy figure to divide into half.
You can see on this pic, my 'scratcher' is a little larger than it needs to be, it could be used as is, but some of the effect would be lost.
Normally I would spin the bit against a grinding wheel dressing stone to get it to size, but in this case, because I couldn't find my one, I used a bit of looped rough emery. It did the job, but it was a lot slower. On no account do it against a file, it will remove the file teeth without a pause for thought.
Now we got size (or near enough it doesn't matter).
If you looked at the last link that I posted, it should give you some idea of the effect you require. Most people go for the standard fishscale effect, starting at one side or end and work your way across or down. Being an awkward a**ehole, I like to do my favourite one, that is starting in the middle and by swapping from side to side, eventually get to the outer edge. I prefer this one as it gives a more even holographic effect than the fishscale one, when viewed from certain angles.
This is where my little book comes in, I find the centre of the plate, and draw up a diagram of the pattern and offsets. Doing it this way, I can always refer back for my offsets and put my mind straight again. A quick calculation and I am back on course.
'Scratcher' centred up on the job, and aligned with the end of the plate.
Notice how close it is set to the plate, about 0.100"(1/10"). This allows the handle to be moved down with a couple of fingers pressure. I do a constant count that is dependent on a test scratch on a similar piece of material. I found on this plate, down with slight pressure on the plate, count to four, release. That will be constant throughout the whole exercise.
Zero, zero, and that is my datum set up for the whole job. Everything from now on works from that point. The Y will always be a multiple of 0.250"(1/4"), the start of each alternate row will be either a full half inch number or a quarter inch number, followed by half inch spacing. I start at the same end for each row, but you could just put in your sideways and endways offset, and go back up the row. But you must remember that each row either side of centre, should be started at the same end as the opposite one the other side of centre. Confusing isn't it? Now you see why I am totally brain dead.
This is the first run from datum to the other end with a 1/2" pitch.
Before going further, I will explain about lubrication, if you are using this dry stick method. Without lubrication, the stick will quickly burn out and erode away.
Eamon Keogh suggested to use WD40 as a lubricant, rather expensive if bought in the spray cans, and on this job I have used it for convenience. Normally I would make my own lubricant out of either white spirits or paraffin, with a dash of 3 in 1 oil, shaken not stirred. I usually paint a stripe of it down the line run and just go for it.
So using my pattern, wind back to the datum start.
Then put my offset in for the next run. The third run will be on the opposite side of centre and so on.
I had had enough by the time I got this far and couldn't concentrate any more, about two hours accurate work. I am lucky in that when I turn my machine off, the DRO remembers where it was, so I could pick up the job again anytime, as long as the plate wasn't moved out of the vice. If yours won't allow you to do that, or you are handballing it with the dials, you have two choices. Either carry on and finish it, or stop when you reach a known datum, and write it down, then restart on the known datum of where you stopped.
This pic looks like a crap finish, engine turning never looks right in a straight on light.
This is what it looks like in oblique lighting, and shows the normal effect the eye would see.
There are very many ways of doing ET, from handballing with an electric drill, thru running down the edge of a ruler under a drill press chuck, to what I am doing here. None are wrong, if the effect suits yourself, it is correct.
Give it a quickie go, you just might impress yourself.
I will finish this job off when I can get back to it, and show you the finished result on my next post.
Bogs