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I have some questions regarding workpiece setting and holding. I have a Proxxon MF70 and a 'Heinz' 8mm watchmakers lathe because they seemed most suited to 2mm scale work and they have to live in the spare bedroom along with the layout and other toy train items, along with a desk for my wife's card making stuff.

 

I have a machine vice for the MF70 but the square nuts do not run in the T slots accurately enough to ensure that it is square on the table. After a lot of faffing about I seem to be able to get it close enough, checked by making a cut and measuring the difference from one end of the piece to the other. When I come to start machining I make an educated guess where the edge is based on when the cutter first starts removing material feeding in really slowly and setting the zero there. There must be a better way?

 

When milling right through, for example when profiling (just as an example), how do you protect the table? Should I just add scrap under the workpiece? How do you use the step clamps and retain the part when the exterior waste is removed at the final cut whilst allowing access for the cutter (I hope that makes sense)?

 

My 'budget' for this is not entirely spent and I see that also available is a dividing table and an engraving attachment. The latter looks like it could be usefully employed for pantograph milling? I wondered if they were worthwhile acquiring?

 

Finally onto the lathe: I have a 4 jaw chuck for this, which I acquired from RDG tools (usually disclaimer). It is supplied with the correct part to fit into the headstock and threaded to suit the drawbar. How do I go about setting work up in this with minimal run-out?

 

Lots of questions in a short space and I hope you don't mind but I saw the opportunity to release all my queries in an appropriate (I hope) forum. I have read back all 17 pages over the last few days with interest, but most of it is a bit big for me.

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I have a machine vice for the MF70 but the square nuts do not run in the T slots accurately enough to ensure that it is square on the table. There must be a better way?

 

When milling right through, for example when profiling (just as an example), how do you protect the table? Should I just add scrap under the workpiece? How do you use the step clamps and retain the part when the exterior waste is removed at the final cut whilst allowing access for the cutter (I hope that makes sense)?

 

My 'budget' for this is not entirely spent and I see that also available is a dividing table and an engraving attachment. The latter looks like it could be usefully employed for pantograph milling? I wondered if they were worthwhile acquiring?

 

Finally onto the lathe: I have a 4 jaw chuck for this, which I acquired from RDG tools (usually disclaimer). It is supplied with the correct part to fit into the headstock and threaded to suit the drawbar. How do I go about setting work up in this with minimal run-out?

 

Lots of questions in a short space and I hope you don't mind but I saw the opportunity to release all my queries in an appropriate (I hope) forum. I have read back all 17 pages over the last few days with interest, but most of it is a bit big for me.

 

Hello richbrummitt,

 

you wont be rich for that much longer.

I presuming that the Proxon MF 70 is a type of milling M/C. To set the "vice up" you really want a dial test indicator (clock) and magnetic base. You then nip up one of the bolts that hold down the vice and run along the vice jaw (the fixed one) and take a reading from the loose end (not that loose, just have a nip on it) then tap the vice in the direction to bring it to the same reading as the first end. Then check the first end and see how it is, then do the same again until you get the same reading at both ends.

 

I don't think that the MF 70 can be used as a profile miller as the profile miller follows a pattern around with a styles and copies out the parts.

 

For a four jaw chuck you have to sett all the jaws to get the job to run true. If all you want to do is round work, I think that you'd be better off to get a set of colletts and holder , or a 3 jaw chuck.

 

Machining ante some thing that up pick up over night it takes a bit of time.

 

I hope this helps you, with a bit of luck Birtiedog will also help

 

OzzyO..

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Finally onto the lathe: I have a 4 jaw chuck for this, which I acquired from RDG tools (usually disclaimer). It is supplied with the correct part to fit into the headstock and threaded to suit the drawbar. How do I go about setting work up in this with minimal run-out?

 

Again you need a DTI (Dial Test Indicator). Chuck the material then set up the DTI so that the needle touches the workpiece. Spin the chuck by hand whilst watching the DTI then centre the workpiece by alternately loosening one jaw then tightening the oposite jaw. This takes time and practise. A 3 jaw chuck is more conveniant, but not as accurate as collets. Soft jaws specifically turned to suit the workpiece certainly help though.

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you wont be rich for that much longer.
perhaps not but hopefully I can enjoy these things.

 

I presuming that the Proxon MF 70 is a type of milling M/C. To set the "vice up" you really want a dial test indicator (clock) and magnetic base. You then nip up one of the bolts that hold down the vice and run along the vice jaw (the fixed one) and take a reading from the loose end (not that loose, just have a nip on it) then tap the vice in the direction to bring it to the same reading as the first end. Then check the first end and see how it is, then do the same again until you get the same reading at both ends.

 

How do you move the dial indicator from one end to the other and back whilst knowing for certain that it is in the same plane? Actually I just realised that you fix the dial to the pillar/base and move the table don't you?

 

I don't think that the MF 70 can be used as a profile miller as the profile miller follows a pattern around with a styles and copies out the parts.

 

What about with this: http://www.proxxon-direct.com/cgi-bin/sh000369.pl?REFPAGE=http%3a%2f%2fwww%2eproxxon%2ddirect%2ecom%2facatalog%2findex%2ehtml&WD=ge70&PN=Engraving_Device_GE70%2ehtml%23a27102#a27102 If this can be used how I think then it would be possible to set at 2:1 and trace 4mm drawings to 2mm parts?

 

For a four jaw chuck you have to set all the jaws to get the job to run true. If all you want to do is round work, I think that you'd be better off to get a set of colletts and holder , or a 3 jaw chuck.

 

I have a part set of collets that includes all the sizes I need to use thus far. I got the 4 jaw for items that are bigger than the 8mm collets go up to. Ive been building up this collection for several years now.

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perhaps not but hopefully I can enjoy these things.

 

How do you move the dial indicator from one end to the other and back whilst knowing for certain that it is in the same plane? Actually I just realised that you fix the dial to the pillar/base and move the table don't you?

 

"Yes that's correct you move the table along. One thing you may have to watch on a M/C of this size is that the cross slide doesn't move when you tap the vice, so keep it locked."

 

 

What about with this: http://www.proxxon-d...l#a27102#a27102 If this can be used how I think then it would be possible to set at 2:1 and trace 4mm drawings to 2mm parts?

 

"Looking at it you should be able to make parts with it, but it would be better to make plasticard patterns at 10mm ; ft. and use the 5;1 reducer for the small parts (are any parts big in 2mm?). One of the problems that I can see with just tracing a drawing is keeping the stylus steady along straight lines. One thing about making templates is that you can repeat the parts by just following the template."

 

I have a part set of collets that includes all the sizes I need to use thus far. I got the 4 jaw for items that are bigger than the 8mm collets go up to. Ive been building up this collection for several years now.

 

"I think that I'd still get a 3 jaw chuck as well."

 

 

Sorry how my replies have al ended up in the main text so I've done them in blue and bold.

 

There was a couple of articles in M.R.J. a couple of years back by Tony Reynalds that should help you.

 

If you want to have a chat about it drop me a PM with your land line number and I'll call you back.

 

OzzyO.

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How do you move the dial indicator from one end to the other and back whilst knowing for certain that it is in the same plane? Actually I just realised that you fix the dial to the pillar/base and move the table don't you?

 

You do indeed.

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  • 7 months later...

 

I met my old metalwork teacher a few years ago and he just had to remind me that the chuck key that I had forgot to remove " is still embedded in the workshop ceiling " cool.gif. That was over 30years ago blink.gif.

 

ATB, Martyn.

Sounds like an excuse to go and see if you ask me lol

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Setting up a 4-jaw is easy, but time consuming.

 

Once done, they tend to be more accurate than a 3-jaw.

 

The method I got taught at college was to mark opposite jaws with chalk and set marked and unmarked up seperately until it's basically there, then run it round by hand slowly adjusting until it showed the required tolerance on the DTI (ie no movement).

 

Even a 3 jaw chuck can be out of concentricity if you remove then replace the workpiece so a dial test indicator is useful. One real sin is to hit the chuck with a mallet as i once saw someone do. That would just put the spindle out if you were working in 4mm scale.

 

I was taught as a rule of thumb do all the drilling operations first then turn the work as then you know the hole and turned diameter of the workpiece are concentric in relation to each other.

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  • 7 months later...

I've recently bought myself a Unimat, and I want to change the power switch. The machine is bolted to a wooden baseboard and has a switch screwed to the board, limiting the use of the machine as I cannot move the motor and set up the machine as a mill (its in lathe mode at the moment).

I want to fit an in-line rocker type, which is what would have been fitted originally.

The motor is rated at 90 watts and runs on 230 volts. Does anyone know if a standard lighting type 6A/250V switch would be suitable? (This is the type I have in mind.)

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Hi Pete,

By in-line I mean that it has to be part of the mains cable, like a lamp switch. I can't find any double pole ones though so Ive ordered the one in the link above.

To use the machine (Unimat SL, mine's here) as a mill the entire headstock including motor is unbolted from the machine bed and set up on a column which means that the switch cannot be fixed in one position.

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I've recently bought myself a Unimat, and I want to change the power switch. The machine is bolted to a wooden baseboard and has a switch screwed to the board, limiting the use of the machine as I cannot move the motor and set up the machine as a mill (its in lathe mode at the moment).

I want to fit an in-line rocker type, which is what would have been fitted originally.

The motor is rated at 90 watts and runs on 230 volts. Does anyone know if a standard lighting type 6A/250V switch would be suitable? (This is the type I have in mind.)

 

Should be fine as far as current is concerned as a mains 90W motor should only be drawing ~0.4A.  As others have mentioned, a double pole switch would be better for full isolation but, as long as you ensure the switched side is on the live wire I wouldn't see the installation as actually dangerous.  I don't know what the law says though.

 

Something else you might consider is a sewing machine foot switch.  Dead-man protection and hands free operation in one unit.

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Many thanks to all that have taken time to reply. I've ordered the switch that I've linked to.

 

PatB - I did consider a foot switch, I have one on my RSU. The dogs sometimes stand on it, not much of a problem when soldering but dog activated lathes would be quite a different matter!

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  • 3 months later...

The 'Workshop Practice Series' is a very useful collection of handbooks - or be like me, and do a 5 year engineering apprenticeship biggrin.gifbiggrin.gif .

 

There are a number of books in this series relating to using the lathe. Which one would you recommend for a beginner ? I am thinking of buying both #34 and #43.

Edited by brian777999
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As things are a bit quiet here I thought I would go back and re-read the whole thread again as I am as stated on another thread putting together plans to buy a SIEG SC3 Lathe (haven't decided from where yet) but am interested to know what would be the best tooling and additions to buy from the start and what to look to buy in the future based on the fact that people say you buy as much tooling as the lathe its self. I realise that there are different tools for different jobs but I am going to start my self off with cutting some track gauges and turning down some wheels. I look forward to any advice

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