Power feed for a Sieg SX2.7 mill

[sploo]

I've recently acquired one of the many Sieg SX2.7L clones. Unlike my mini mill, the left side of the table has no handwheel but instead has a slot on the end of the leadscrew for an optional power feed. The official power feed is over £300, but I have various "bits" I've collected over the years for other projects, so...

I turned a ring to mount a 24V 6000rpm brushed motor, and milled a slot in the shaft to interface with an Oldham style coupling:

The ring got a few more tapped holes, and the motor was mounted on an MCP-4 25:1 reduction gearbox (obtain used on eBay about 20 years ago ):

With the end of the table removed, the slot on the leadscrew can be seen:

I machined a plate to help interface the gearbox to the end of the table, and also a shaft that slots into the hollow axle in the gearbox:

Later a knob was added to the end of the shaft to make it easier to slide. Note the slot in the shaft, that will line up with the hole in the gearbox's hollow axle:

The end of the table got two new holes drilled and counterbored, and those holes were used to mount two tapped lengths of steel rod:

Rods and plate mounted to the table:

Gearbox and motor mounted to the plate. Note how a bolt through the hollow axle captures the shaft, and allows easy engagement/disengagement of the power feed:

Next a 3D printed cover was added to protect the "clutch" from chips:

Final shot of the mounted power feed:

Next it was on to the control box for the motor...

 

[sploo]

I 3D printed a front and back plate for the control box. The rear faces have a slot for some aluminium plate:

I picked up a cheap motor controller on Amazon (https://www.amazon.co.uk/dp/B07H7HT66B?psc=1&ref=ppx_yo2ov_dt_b_product_details):

The controller was modified; a better toggle switch was installed, and a momentary push button switch was added to the potentiometer. The red and yellow lines from the pot carry the resistance, so passing them via a switch that can short the wires together provides an instant "go to 100%" option (on this motor controller high resistance => low speed, low resistance => high speed):

Front panel components mounted:

I don't have any sort of metal brake, so bending some alum plate for the enclosure was a bit hacky, but gave an acceptable result. I might later replace it with a 3D printed enclosure:

Testing:

And finally on the mill:

I haven't chosen a final position for the control box yet; which is why the lead from the motor is unfinished. I'll likely decide once I've fitted a DRO to the mill.

I've also now printed a "cup" like cover for the motor, as its magnet attracts chips.

Below a certain speed range the motor doesn't have enough torque to drive the table, but it will practically move the table from about 30mm/min up to 500mm/min (I've tested 30mm/min with a fly cutter but not a milling cutter yet).

There's no limit switches (I have an idea how to add them, but I'll have to see if I have space to fit them). I might replace the steel bolt that goes through the hollow axle and drive shaft with something made from plastic (maybe even 3D printed) and see if it stands up to normal use. If so it could provide a good weak link to protect other components from damage in the event of a crash. I'm sure I'll get round to trying one just after I first get a nasty crash

 

[Sideways]

Excellent.
Good job and thanks for sharing it
If this was a Bridgeport, the bolt on motor drives equivalent to what you have done here are pretty expensive and your self build represents a substantial saving.

I've noticed that you can buy simple variable speed control boards for turning individual stepper motors. Steppers have high torque at slow speeds so this may be another way of solving the same problem. With a stepper, you could omit the gearbox but might need a higher current power supply so similar overall project.

 

[sploo]

Thanks.

Yea, I did consider a stepper (I even have a pretty chunky stepper motor to hand) but decided that the brushed motor + gearbox was the better use of bits I had spare.

One other benefit of this solution is that it's quite thin; adding just 12cm to the left side of the table. That's useful as I'm a bit limited for space in my garage.

 

[Fergie 307]

Similar on an Amadeal 25, but using one of the motor units made for the likes of Bridgeport. Problem I had was that the power feed sold for it runs ridiculously fast, I think the slowest speed was something like 90mm/min. Made the adaptor plate from a section of heavy rolled channel and milled out the web to get a flat mounting surface. Runs as slow as 10mm/min and doesn't project above the table. Also doesn't interfere with hand operation so you can still use the handwheels at the other end without needing a clutch.

 

[Fergie 307]

The motor is of course Chinese, and cost about £80 on e bay. Seems very well made. Also comes with an auto stop switch you can fit to the bed. The thick piece at the top shown in the second image is the mounting bracket it came with, just remachined to attach to the main end plate and provide support and a mounting for the thin alloy cover. The handle has been reduced in length by half so it doesn't hang down too far. I plan to move the machine soon, and will then probably put a piece of half inch plate under it to lift it slightly, as at extreme travel the handle on the power feed hits the side of the tray. Apart from making the new end plate the only other work was to modify the end of the shaft on the machine to take the drive gear which came with the power feed. I Made a flat on the shaft, then a threaded collar which is a press fit into the gear. Then screws onto the shaft and retained by a grub screw on the flat. There is a separate plate fitted over the main mount machined from alloy which holds a ball bearing race for the end of the shaft. The motor is intended to shift the much larger table on a Bridgeport, so has massive torque. Can run from under 10mm/min up to 300. The tray is just a commercial baking tray. Only bad thing about the machine, which is generally well made and finished, was the tray. Dreadful thing which went straight in the bin!

 

[Fergie 307]

And I should point out that the picture isn't reversed, it is fitted to the right hand side, this was to ensure that it sits flush with the table. The bracket that comes with it is intended to be fitted on the left, but then leaves it about an inch above the table, no use to me as I wanted the table unobstructed. So I just turned it upside down and made my own bits to fit it on the other end.

 

[ChaiLatte]

This is more for discussion than critique.

Are you ever likely to want to cut at 100% speed (i.e. rapid speed, equivalent to having the button pressed)?

Could you gain more resolution (finer control over the range of actual, sensible cutting speeds) on the potentiometer by putting a fixed resistance somewhere?

A speed limiter on the potentiometer-controlled pixie path might save a mistake if you sneeze at the wrong moment and turn it up to 11.

 

[Fergie 307]

I 3D printed a front and back plate for the control box. The rear faces have a slot for some aluminium plate:

View attachment 157219

I picked up a cheap motor controller on Amazon (https://www.amazon.co.uk/dp/B07H7HT66B?psc=1&ref=ppx_yo2ov_dt_b_product_details):

View attachment 157220

The controller was modified; a better toggle switch was installed, and a momentary push button switch was added to the potentiometer. The red and yellow lines from the pot carry the resistance, so passing them via a switch that can short the wires together provides an instant "go to 100%" option (on this motor controller high resistance => low speed, low resistance => high speed):

View attachment 157221

Front panel components mounted:

View attachment 157222

I don't have any sort of metal brake, so bending some alum plate for the enclosure was a bit hacky, but gave an acceptable result. I might later replace it with a 3D printed enclosure:

View attachment 157223


Testing:

View attachment 157224

And finally on the mill:

View attachment 157225


I haven't chosen a final position for the control box yet; which is why the lead from the motor is unfinished. I'll likely decide once I've fitted a DRO to the mill.

I've also now printed a "cup" like cover for the motor, as its magnet attracts chips.

Below a certain speed range the motor doesn't have enough torque to drive the table, but it will practically move the table from about 30mm/min up to 500mm/min (I've tested 30mm/min with a fly cutter but not a milling cutter yet).

There's no limit switches (I have an idea how to add them, but I'll have to see if I have space to fit them). I might replace the steel bolt that goes through the hollow axle and drive shaft with something made from plastic (maybe even 3D printed) and see if it stands up to normal use. If so it could provide a good weak link to protect other components from damage in the event of a crash. I'm sure I'll get round to trying one just after I first get a nasty crash

For limit switches all you need is a button fitted into the slot on the front of the bed, or use the ones it came with. Then just a plunger or blade microswitch which will close/open (depending what suits your wiring) when it gets to the button.

 

[Fergie 307]

This is more for discussion than critique.

Are you ever likely to want to cut at 100% speed (i.e. rapid speed, equivalent to having the button pressed)?

Could you gain more resolution (finer control over the range of actual, sensible cutting speeds) on the potentiometer by putting a fixed resistance somewhere?

A speed limiter on the potentiometer-controlled pixie path might save a mistake if you sneeze at the wrong moment and turn it up to 11.

Only time I use the high speed is to return the work for the next pass, quite handy being able to whizz it back rather than winding away at the handle!

 

[sploo]

Similar on an Amadeal 25, but using one of the motor units made for the likes of Bridgeport. Problem I had was that the power feed sold for it runs ridiculously fast, I think the slowest speed was something like 90mm/min. Made the adaptor plate from a section of heavy rolled channel and milled out the web to get a flat mounting surface. Runs as slow as 10mm/min and doesn't project above the table. Also doesn't interfere with hand operation so you can still use the handwheels at the other end without needing a clutch.

I've seen those on eBay. I assumed they would be a bit large for the SX2.7 mill but that's a very clever way of mounting it.

 

[sploo]

For limit switches all you need is a button fitted into the slot on the front of the bed, or use the ones it came with. Then just a plunger or blade microswitch which will close/open (depending what suits your wiring) when it gets to the button.

I've got some NC (normally closed) switches, so the intention was to wire one switch inline with the toggle switch signal for left movement, and another for right. As such, when one got triggered it would stop the table travel in that direction (effectively making it as if the switch was turned off), but still permit the table to be moved off the limit switch under power. Now that I know the basic power feed works, once I've installed the DRO scales I'll probably revisit the placement and wiring of switches.

I'm planning on mounting the DRO scale for the X axis to the front of the table, as putting it on the rear limits the range of Y movement; which has been a major bugbear for me on my mini mill.

 

[sploo]

This is more for discussion than critique.

Are you ever likely to want to cut at 100% speed (i.e. rapid speed, equivalent to having the button pressed)?

Could you gain more resolution (finer control over the range of actual, sensible cutting speeds) on the potentiometer by putting a fixed resistance somewhere?

A speed limiter on the potentiometer-controlled pixie path might save a mistake if you sneeze at the wrong moment and turn it up to 11.

Not quite sure I understand; but Fergie's point about high speed is what the button's for - allowing quick traverse of the table back for the next cut.

It's fairly easy to set the travel speed with the potentiometer, and the table will then only move when the toggle switch is moved from its central position (to the left or right).

I do need to work out a good (fixed) place for the control box though; so the controls are always in the same location in the event that I need to get to them quickly.

 

[Fergie 307]

I've got some NC (normally closed) switches, so the intention was to wire one switch inline with the toggle switch signal for left movement, and another for right. As such, when one got triggered it would stop the table travel in that direction (effectively making it as if the switch was turned off), but still permit the table to be moved off the limit switch under power. Now that I know the basic power feed works, once I've installed the DRO scales I'll probably revisit the placement and wiring of switches.

I'm planning on mounting the DRO scale for the X axis to the front of the table, as putting it on the rear limits the range of Y movement; which has been a major bugbear for me on my mini mill.

Fair comment on the scales, I have lost about 25mm by having it at the back. Not an issue for me, but could well be for some.

 

[sploo]

Fair comment on the scales, I have lost about 25mm by having it at the back. Not an issue for me, but could well be for some.

I didn't really think about it that much when I installed scales on the mini mill, but the lack of forward/backward movement has bitten me so many times. This new (to me) SX2.7L has a longer X travel, and a reasonably larger Y travel, so I'm trying to preserve that range as much as possible. I couldn't even fit a Bridgeport under my garage ceiling height, so 1+ ton of "proper" mill is sadly a no go.

 

[Revilo]

Which company was the original vendor? I've not seen one in that shade before

 

[sploo]

Which company was the original vendor? I've not seen one in that shade before

It's a Technology Supplies TS20MD. TS are a supplier of D&T kit to the education sector.

As far as I've been able to work out, they started to list it in 2019 (which appears to be the date code on my machine), but it's no longer in their catalogue.

Ironically, the image on their catalogue (from 2019) is very slightly different to what I have (power socket on the other side of the column, and a metal plate covering the front of the ways rather than bellows). It's actually closer (albeit in blue) to the photo on ArcEuroTrade's current catalogue (No 11). Though I understand Arc now sell a slightly more modern variant with an improved control box.

 

[Revilo]

It's a Technology Supplies TS20MD. TS are a supplier of D&T kit to the education sector.

As far as I've been able to work out, they started to list it in 2019 (which appears to be the date code on my machine), but it's no longer in their catalogue.

Ironically, the image on their catalogue (from 2019) is very slightly different to what I have (power socket on the other side of the column, and a metal plate covering the front of the ways rather than bellows). It's actually closer (albeit in blue) to the photo on ArcEuroTrade's current catalogue (No 11). Though I understand Arc now sell a slightly more modern variant with an improved control box.

Ahh interesting, thanks!
There's at least 5 variations that i've seen and now there's a new "mirror-but also black" model https://www.siegind.com/shop/sx27-bench-mill-drill-led-mirror-display

 

[sploo]

Ahh interesting, thanks!
There's at least 5 variations that i've seen and now there's a new "mirror-but also black" model https://www.siegind.com/shop/sx27-bench-mill-drill-led-mirror-display

That mirror model is very "bling" isn't it

 

[Revilo]

That mirror model is very "bling" isn't it

Perhaps they should do the red highlights with a metallic paint!