Bridgeport wiring for VFD

[Richiew]

Replacement bolts for knee lifting screw. Every time I tackle a job it seems to need more parts which slows my glacial progress still further.
I also ordered some 5/16" 24 grub screws. I only needed one to replace an incorrectly dimensioned one where the grease feeds in near the top of the head.

The spring case arrived today. First impressions were favourable. I was expecting a rough gash down the side. It's been done nicely though with the cut and the relief milling.

Spring tapped in no issue. A pair of pliers needed to pull off the retaining strap once the spring was three quarters of the way down.

This is where I encountered another problem.

Left is the new Chinese case with the Chinese spring installed. Middle, is the original case and on the right is the part that fits in the hole in the middle. It connects the quill pinion shaft to the handle. The Bridgeport case aperture is about 28.50mm, the Chinese one is about 27.69mm depending on how my Aldi calipers are feeling. The thing on the right is 28.5mm across and doesn't fit the Chinese case.

Onto the lathe. Please excuse the disgraceful amount of stick out on the tool. I do know better.

Success.

 

[Richiew]

This is them back on the mill. The end of the quill pinion shaft showing. The spring holding pin is on there too but you can't see it.

This keyed piece that now fits joins the handle to pinion shaft. The spring hasn't been tensioned yet. The screw holes top and bottom don't line up and there's no screws in yet.

All back together, bar one of the screws, which made a leap for freedom. Works fine. The quill stays where you put it. It's not supposed to retract like a drill does.

Top end was back together now so couldn't resist a quick test. I need to swap two of the VFD wires around as we are turning the wrong way when I press start. The CVT works fine varying the speeds. I must lubricate the top end as Fizzy warned me.

The base goes back together next.

 

[Agroshield]

With the non-countersunk knee-nut screws, is there anything up inside the knee that could hit them when the knee is lowered as much as it will go?

 

[Richiew]

I honestly don't think it drops that far, Agroshield. That spring cover has a minimum height of about three inches collapsed and that sat on top of the nut for years, reducing the travel. I'm not sure the spring cover is going back on but I can't see the nuts being an issue. With my current mill I usually work at the top end, milling small stuff. I can't see me decking any engine blocks and needing the full height.

 

[Richiew]

Got dragged out of the garage at 11pm this evening. Mill has just about gone back together today. Gib repair seems a success. It got fitted, removed and refitted without issue. Nothing jammed or broken this time. I have shimmed it 4 thou too. I put the original gib plunger back in with the worn spacer flipped around so the worn face didn't register. The clamping system appears to work now, it's about adequate. I don't think it is the best design. One indirect clamping mechanism, subject to wear. My little Marlow mill has two screws clamping directly against the gib. The ergonomics are much better on the Bridgeport though. I have to reach around the side and over the table with the Marlow but the Bridgeport clamp is to hand at the front of the knee.

I found my missing screw and refitted it.


This is the state of play this evening. Power feed needs fitting to the right hand side, Wipers need fitting to the front. I may have to adjust the backlash again on the X and Y feed nuts. I can get at them without dismantling the whole thing.


I ran the mill head under power again. The power downfeed works, the spindle brake doesn't, unfortunately. I can probably manage without it using an ER40 collet chuck as it has flats to lock it still when changing tools. My R8 collets might have an issue.

DRO needs refitting if the delicate read heads still work after being dismantled. I'm looking to replace it in future with a 3 axis system. That's one of my reasons for the new knee screw and nut.

I have some paint coming which is a reasonable match for the green. RAL6019. I just want to cover up the dark green strip down the middle.

My estimates are always terrible but I'd like to make some chips by the end of Monday at the latest.

After that, the table holes need filling and maybe a basic remote start stop switch box for the VFD. I can leave the motor at 50hz as there's CVT on the mill, so no potentiometer needed.

 

[Richiew]

I gave up on the power feed and refitted the manual handle. I think the power feed was only trial fitted previously as the screws for the power feed end plate are too long and they really only suit the manual end plate which is thicker bodied. I couldn't get everything to fit correctly and get the handle bolted back on. I've ordered shorter UNC allen screws to have another go. Should have taken more pictures when I was dismantling months ago.


Got the machine quickly set up. Had to rotate the head to fit the drawbar but now it is in I shouldn't need to bother in future. Aliexpress ER40 collet chuck fitted. I couldn't get the front way wipers fitted. The new felt wipers are too thick and the screws are consequently too short. Some #10 32tpi countersunk screws ordered. I've also ordered a load of 1/4" 20 tpi screws of various lengths as they seem to be all over the machine too.

First chips, this is a 3/4" roughing mill so no fine finish expected here. I haven't trammed the vice or the head yet. Was rushing before being called in for dinner like a ten year old. The knee clamp turns out to be more effective than I expected. I did my usual trick of trying to raise the table with the knee lock clamped and it stayed stuck despite me cranking on it. All is forgiven and I take it all back.

Had a very quick go with a 12mm 4 flute end mill. Everything is new to me and there's three times the power of my old mill so I haven't developed a feel for it yet. The Marlow complains if you over do it but I haven't trained my ear for the Bridgeport yet. New vice too. Proceedings came to an abrupt halt. Broken end mill. No harm done really. These bigger machines feel much safer as the long table means you are further away from the business end when manually feeding.

Think I'll try filling the table holes tomorrow after a little play. Temporary way covers may be a good idea too. DRO needs fitting back on as well.

 

[Agroshield]

The power downfeed works

I have read that the power downfeed on a Bridgeport is not so heavy duty and should not be used for anything much over a 3/8" drill. I do not know if that is true, but mention it so you do not break something by overloading it.

The new felt wipers are too thick

Would soaking them in oil and leaving squeezed in a vice overnight allow them to be installed?

 

[Richiew]

Cheers for the downfeed info Agroshield. I have it on my TOS drill and never dared use it to be honest. Too much to go wrong. I think I'd only try it on the Bridgeport if I wanted a decent surface finish with a boring head which shouldn't be too much for it being light cuts.

I had soaked the wipers but they are good quality thick stuff. I bought some in the end to save time. Screws are ordered now so I'll wait. I'll use the felt that I do have to fill in the gap in the middle.

 

[Richiew]

When I fixed the clock spring and removed the clutch mechanism on the other side, the gear for the power feed could be seen if I identified it correctly. It was bronze and pretty narrow so I am sure you are right Argoshield.

 

[Richiew]

Pics of some little jobs. Wipers fitted. They cover the important bits but leave large gaps for chips to accumulate behind the wiper plate so I used the way felt I had to plug the gaps. Did the same on the rear side of the saddle which mirrors this one. New table lock handle fitted too. Way covers have been ordered from Aliexpress. The longer screws may help here as I think the covers use the wiper plates screws for attachment.

DRO refitted. It still works despite the delicate read heads left for months in a plastic bag on the base. The paint I ordered was a poor match. Tried adding some darker green paint to it but still looks wrong. I'll let it dry properly and smear it with fresh oil in the hope of toning it down. It will be covered by the rear way cover soon so won't be seen.

Most of the many holes on the table got filled with JB Weld. Need to decide on a mounting spot for the VFD and make up a simple stop/start control box. The power feed wants fitting at some point but not too bothered about that right now.

 

[Richiew]

A few more bits on this.

Way covers from Aliexpress. They aren't an exact fit, but they do the job. The column cover is just a slab of rubber with a pair of metal strips at each end. The bellows covers are much better.

The column cover if held up with old fishing line tied round the column. It is screwed to the saddle using the bolts than hold the wiper covers on plus a pair of strong magnets.

Again, attached to the saddle using the wiper screws. I have a bootlace threaded through the steel plate at the front and tied around the bearing holder plate for the Y axis screw. Temp measure until I think of something else.

The primordial soup in the base was removed using a big oil transfer syringe. It was 90% water (Old coolant?) with thicker oil on the top. This is just a sample. There was a lot more.

Marigolds got borrowed and the two pits dug out.

In one the pits I found a couple of bits of steel and makeshift T slot bolt.

 

[Richiew]

Squared up the head, removing any nod or lean. There seems to be a lot of expensive tools on sale to help with this but I made do with the indicator in the pic shown below. Did the usual sweep front to back and then side to side to get the head reading even. The table looks in a poor state and I had to avoid the obvious JB weld areas. I ran a clock across the length of the table out of curiosity and it reads a lot better than it looks. I was surprised.

Started thinking about a control panel for the VFD. Considered something like this pictured below. Decided it was too cluttered so I dispensed with the 10k pot. The mill has CVT so I don't really need the pot. I could always fit the pot sticking out of the top if needed. I already had the latching emergency stop button. The buttons are from Ebay, advertised as arcade buttons. They are a little bit smaller than the ones I remember on the 1980's arcade games and they are microswitched. I wanted a decent sized chunky button and these fitted the bill and are pretty cheap.

Marked up on the side not showing. Pilot holes drilled.

Step drill to 24mm I think.

All the button switches wired up for the COM signal in black. A spare Wago employed to gather them up. It's like a common earth on a vehicle wiring. The emergency stop is wired separately as I'd only ordered 6 core wire plus some four core for the potentiometer which only requires three wires. The emergency stop isn't a true emergency stop as I understand the cheap VFD doesn't do sudden braking. It is a big, easily mashed button to hit in a hurry though.

I have start, stop, Jog fwd, Jog backward, reverse plus the big stop button.

The signal wire is a really narrow gauge, so a ferrule was clamped on to give the brass coloured clips something to grip onto.

All wired up. Wiring colours match the buttons. Two cable glands fitted for strain relief. The wire are very delicate and definitely need it. The tools and items in the picture were used to put it together. All wiring and buttons tested with the multimeter buzzer.

Welcome to Richie's Playskool-My-very-first-Bridgeport-control-panel ™

(Suitable for under fives under supervision.)

I did a lot of research on VFD control for the cheap Chinese inverters. The info is pretty scant if you really don't know what you are doing. I wasn't sure if I needed momentary or latching switches and not many people make it clear in their builds. All the arcade buttons on my build are momentary. The emergency stop happens to be latching. I found two really good sources.

Firstly @My Old Landy's video on youtube.

You may have to right click and copy/paste the URL.

Secondly this thread on the Model Engineer Forum. Thank you very much Martin of Wick from the Model Engineer forum.

AT1 inverter 3 wire control | Model Engineer & Model Engineers Workshop

Model Engineer and Model Engineer Workshop are leading magazines for modellers, with reputations for bringing you the best tips, tricks, and inspiration from the modelling world. From miniature steam locomotives to clocks and automata, get the most out of your builds with Model Engineer and...

www.model-engineer.co.uk

I have copy/pasted his findings below in italics as the info is worth repeating. All credit goes to Martin.

For anybody struggling with the XSY AT series VFD manual cryptic control parameter descriptions, based on my limited testing. I hope this will be useful to someone. Further details set out below:

As suspected, all 6 of the analogue inputs are configure as active high, meaning the control logic is activated by an input signal and not an interruption of signal. There appears to be no way of changing this.

The VFD in its default state set no signal input to the non running condition.

The permissible control inputs are restricted, but do allow for continuous contacts via a latching switch (described as 'wire' switching, or momentary contact via a non latching push button arrangement described as 'key or keying'. The more useful input parameters for the 6 analogue input block locations 50 to 55 are as follow:

PARAM 1 wire control stop This changes the VFD default condition to run on power. With contact between com and terminal, the attached motor will not run. with no contact, the device will revert to the previous control state. It is unlikely that many workshop users will need to use this parameter.

PARAM 2 keying stop should really say key start/stop This uses a single non latching push button control to activate the motor. Push the button once for on, push same button again to turn off. It requires a contact set that is NO, or 'push to make' linking com and the terminal set as P2. useful if you only have one button!

PARAM 3 keying operation This changes state from deafault non run condition to the motor run condition and uses a single non latching push button control with a contact set that is NO. Pushing the button starts the motor, further button pushes have no effect unless the status has been changed by the input to another terminal.

PARAM 4 stop keying This changes control state from the run condition to a stop condition and uses a single non latching push button control with a contact set that is NO. Pushing the button changes motor run state to motor off but will have no effect ( it may however interrupt jog mode if pressed during jogging ops). P3 and 4 are used normally used together to effect two button RUN and STOP controls (if that is what you want).

PARAM 5 and 6 wire forward operation wire reverse operation These require a latched contact between com and terminal. Forward and reverse are relative conditions, so need to be set in the context of your particular application. used if a toggle switch or rotary switch operation is required. For example, you might set com on the centre of a 3 way switch wit rev one way and forward as the other. HAVE A CARE as leaving the machine switched to run and starting the VFD a couple of days later without remembering will result in a start up on powering the VFD. you may want to set parameter 1 in location 65 to avoid this.

PARAM 9 wire reversing switch This changes the run state from forward to reverse. When latched, setting the motor to run by another terminal, will cause the motor to run in the reverse direction. Unlatching will restore the original direction of rotation. Normally used with a simple toggle/rocker switch in conjunction with a wire run or key run input.

PARAM 10, 11,12 keying commands These are not well described in the manual. P10 should really say Key forward/reverse switching). They are all momentary inputs requiring non latching NO push button control. P10 allows a single push button to change motor direction, pressing the will reverse the current run direction and so on backwards and forwards. This function will only operate in conjunction with other keying commands (ie P3 or 11 or 12 in the active condition). P11 will start the motor only in the forward direction, P 12 will start the motor only in the reverse direction.

PARAM 17,18 jog forward / reverse Self evident, use if you want a jog function. Can be used with a latching switch to connect com to terminal to hold in jog or NO non latching if you just want to 'blip' the rotation for a part rotation. See params 86 onward for controlling the jog frequency braking etc.

PARAM 19 E stop FWIW, a stop switch and all round missed opportunity. Requires a NO contact mode for your e-stop input. Can be implemented as latching or instant. Latching is preferable as it sets an interlock and prevents normal or jog start until unlatched. If you don't have a latching e-stop, I suggest you also wire into another terminal set with P16 so it sets a fault condition at the drive as ERR 9 preventing further unwanted starts until the cause of the panic has been sorted and the VFD re-set.

Unfortunately, there appears to be no way of setting a braking function on the E-stop, the condition when you most want to stop the rotation instantly. You can set the brake to operate on the normal stop where you don't really need it, but it doesn't implement in the E-stop. Grind your teeth in rage if you will, but remember how little you paid for the device.

Thanks and all credit to Martin from the Model engineer forum.

 

[Richiew]

My vfd bolted to the side of the control box. It is out of the way but not too out of the way. Two bolts out of four with Nylocs.

This is what it is replacing.

Am thinking of using this bracket which held the old control panel.

Maybe like this but it might be too low. It needs to clear the Y axis DRO scale as it comes forward so it can't be set too high.

Maybe like this as I test the strain relief. I think I'd rather have it as a pendant hanging from the ceiling but that might get in the way there too. I don't honestly think there's a perfect place for it.

I still need to wire the control box to the VFD and program the VFD to the buttons but that should be straight forward.

 

[My Old Landy]

Nice clean job my friend

 

[dieselsamurai]

Im about to embark on a similar journey so this stuff is gold to me , still got to get mine apart from where it is and back to my workshop . Seems points not to go through it top to bottom now while it will be apart.

the quill drops slightly when the down feed handle released im hoping that its out of adjustment and not broken

will definately need to go through the lube system as it appears in the same state as yours

Im hoping to resurrect the power feed as I wouldnt do without it on my other mill, trouble is im 99% sure its a 50vdc motor and theres a lot of gubbins in the control box that i have yet to understands its function

may need advise soon !

 

[Richiew]

Bridgeports are really nice to fiddle about with. The bottom half is a really simple design. They come apart and go back together no problem at all really. This probably explains the thousands of rebuild videos on youtube. I have not ventured into the head on mine. It probably needs looking at going by the sound it makes but it is fine for now. I lied in one of my earlier posts. The spindle brake does work. The brake lever is cammed so it needed pulling up and not just rotating. I'm blaming a youtube video for duff info for that one.

Parts aren't cheap but most are available. If you are going split the machine then be aware the table is very heavy.

H&W machine repair is a good youtube channel to watch. The bloke rebuilds them for a living and knows his stuff.

 

[Richiew]

Good rebuild here.

Would you take a punt on this bridgeport vari speed milling machine?

Got a chance to pick up this bridgeport vari speed head milling machine for £250 Obviously it’s been left a while but it has been indoors just a cold damp old barn I always wanted one and don’t mind a project but I don’t know it’s history and it could be junk but probably worth the money in...

www.mig-welding.co.uk

 

[Richiew]

I should probably add that there is nothing so expensive as a cheap Porsche Bridgeport. At least you have some tooling with yours.

 

[dieselsamurai]

I should probably add that there is nothing so expensive as a cheap Porsche Bridgeport. At least you have some tooling with yours.

I have been down this route many times before but its a keeper so I know its going to cost me one way or another , Ive always wanted one and like a challenge

At least its not as rusty as my lathe when I got it !

 

[Richiew]

It will be worth it. It always makes me smile when I walk into the garage. Really chuffed with mine.