# My Table traverse for Chinese mill.



## BaronJ (May 26, 2014)

Hi Guys,

Since my Chinese mill does not have a motorised table traverse and I don,t fancy paying the rather exorbitant prices that are wanted for them I have looked at a lot of designs on the web and decided to have a go at building one.   
Also its a pain, in more ways than one, standing there winding the table back and forth.

So I thought that I would see if I could design and build one from scratch. With this in mind I decided to have a trawl around my local scrapyards for something suitable to use and came across a  car windscreen wiper motor.

I found this one from a wrecked Nissan Micra. Being lazy, I grabbed this one because it was very easy to get it off the chassis bulkhead. Four hex head bolts and it fell out.  The power connections were a very convenient plug and socket attached to the back of the gearbox.

At this point I didn't know what condition it was in, only that it was quite clean with only a little rust on the motor case where the paint had flaked off.

When I chose it I didn't realise that it was a two speed motor, but on testing it, it soon became obvious. It also had wipe home switch built into the gearbox which confused me at first.

Anyway it runs quietly in either direction at both speed settings.  Though I'm informed that these wiper motors don't like being run backwards so that is something to remember.

The photographs show the motor after I had removed the wiring and connections from the back of the gearbox.  Though you can't see it, I drilled out the rivets holding the gearbox together and stripped it down.  The grease inside was more like wax than grease.  So I cleaned it all out and re-lubricated the shaft, gearwheel and pinion.  The gear shaft runs in a phosphor bronze sleeve.

I threaded the holes where I drilled out the rivets 4BA and made a new gasket to go between the two halves of the case.  The original gasket was a line of what looked like hot melt glue. I had to double the gasket material thickness so that the gearbox cover plate didn't bind the gearwheel.  I used 4BA countersunk head screws to fasten the coverplate.

Part of the reason for stripping the gearbox down was so that I could get at the switch mechanism inside and remove it.  It also removed half of the wires that went into the harness socket that was mounted on there.  So now there are only three wires to worry about.  Common, high speed and low speed.

One of the photographs shows the plate that the motor was secured to the car bulkhead with.  The nut on the end of the shaft is M8 and the splines secured the wiper driving arm.


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## purpleknif (May 27, 2014)

I just gutted a 12 volt drill and use a $25 PWM speed controller on mine. Works great. Gobs of torque and a ready made clutch for safety.


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## BaronJ (Jun 6, 2014)

Well it works a treat !!!


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## chucketn (Jun 6, 2014)

Does it run in reverse as easily as forward?

Chuck


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## gus (Jun 7, 2014)

Hi Baron,
Please post working Video. I have one of these DC motors. Are your using a clutch too?

Power Table slide is number 1  on my hit list. Sick and tired of hand cranking.:rant:


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## BaronJ (Jun 7, 2014)

chucketn said:


> Does it run in reverse as easily as forward?
> 
> Chuck



Hi Chuck,

Yes !  The motor always runs in one direction, these wiper motors don't like being run in reverse.  The lever moves a tumbler gear, so you have both directions and a neutral position where the drive is disconnected from the table.  This makes hand traversing very easy.

I'm also examining the potential to include a mechanical limiting mechanism.


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## BaronJ (Jun 7, 2014)

gus said:


> Hi Baron,
> Please post working Video. I have one of these DC motors. Are your using a clutch too?
> 
> Power Table slide is number 1  on my hit list. Sick and tired of hand cranking.:rant:



Hi Gus,

I don't have any equipment to record video.   Sorry !

However a forward, neutral and reverse is obtained simply by moving the lever up and down.  The secret is in the use of tumbler gears, as shown below.




Ignore the dimensions on the drawing they are wrong !  In any case unless you used exactly the same gear sizes that I used they would need to be changed anyway.




Here you can see how I did it.  I machined the wiper motor gearbox housing so that I could press fit a brass bush to support the collar for the tumbler gears.
The gears have 6 mm spindles.  These are simply press fitted into the plastic collar.  The plastic is of the type that is self lubricating.




This drawing does not have the correct measurements but gives an Idea of the layout.
See next post for correct drawing.


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## BaronJ (Jun 8, 2014)

This should be the corrected drawing.  Having posted the original which was wrong and then re-posted the original instead of this one !  Shall we say third time lucky...


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## BaronJ (Jun 8, 2014)

Some more photographs.


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## gus (Jun 9, 2014)

Hi Baron,

Thanks for the fotos and drawings.  Been cracking my head on neutral,forward & reverse.


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## BaronJ (Jun 10, 2014)

gus said:


> Hi Baron,
> 
> Thanks for the fotos and drawings.  Been cracking my head on neutral,forward & reverse.



Hi Gus,

Absolutely dead simple. 

The tumbler rotates to put one or the other small gears into mesh with the big one or neither.  Note that all three small gears are constantly in mesh !  The small one, to one of the two same size ones, and the two same size ones to each other.


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## BaronJ (Jun 12, 2014)

I got another windscreen wiper motor today.  Similar to the other one but the opposite hand and only single speed.


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## BaronJ (Jun 13, 2014)

Seems I got it wrong !  This motor is dual speed.  It uses the case as one terminal.  The two wires give high and low speeds when connected to the positive supply.

I've started stripping and cleaning the gearbox and removing the connector from the gearbox cover plate.  I've drilled out the rivets and tapped the holes M4, made a gasket and used hex cap screws to secure the cover plate back onto the gearbox housing.


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## BaronJ (Jun 14, 2014)

Hi Guys,

This is what I've done so far:-




I removed the two wires going to the motor from the connector block prior to drilling out the rivets attaching the gearbox cover plate to the housing.







The motor and gearbox on this wiper motor are not only half an inch shorter than the other but the drive comes out of the other side.  Unfortunately if I mount this one the same way as the first table drive the motor body will be above the top of the mill table.  It really needs to go below so that it doesn't get in the way when machining something that exceeds the end of the table.




Her you can see the M4 hex socket cap screws that I used to re-fasten the gearbox cover plate to the housing.  You can see the new gasket that I made to replace the original glue line gasket.  This cover plate is also the support for the worm wheel which bears against it.  The worm wheel and its shaft are under slight pressure so there is no end float what so ever in the output shaft.




I wrote the wiring details on the label so that I would know which one did what.  This motor is also dual speed !  It uses the motor body as the common connection to it.






I've already selected the gears that I am going to use for this version from the laser printer gearbox that I was given.  I have two of the black ones shown in the bottom picture.

More to come.


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## BaronJ (Jun 16, 2014)

Hi Guys,

Made some more progress today.  I need a plate to mount the motor.




So sorting through the scrap box I came across this piece of 3 mm thick hard aluminium plate.




After marking it out for the spindle hole and the three mounting screw holes, I needed to make a hole big enough to clear the gear that I am going to put on the motor shaft.  In this case 35 mm diameter.




Not having a hole cutter or a drill this big, I used this carbide router bit.  I've used these cheap router bits several times in both aluminium and mild steel with very good results.  I used neat cutting oil as lubrication and around 350 rpm, feeding by hand as I would a drill bit.  The only downside with doing this is that you get a substantial harridge on the back side of the cut.




The harridge is easy enough to remove with a sharp wood chisel but it tends to scratch the anodising off the surface.




I also used a small router bit to make the countersinks in the three mounting screw holes.  Again using neat cutting oil.

Next step is to mount the drive gear to the motor and check for clearances.  Because this wiper motor has a shorter shaft its sits much closer to the mill table end.

More Later:


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## BaronJ (Jul 9, 2014)

Hi Guys,

Got some more done on the MK2 version.



This is the pair of gears chosen from the laser printer gearbox to be the tumbler gears.  I turned off the long sleeves so that the gears were the same either side, then it doesn't matter which way up the are fitted.  I put circlip grooves 1 mm wide 1 mm down from the end of the shafts in order to retain the gears. 




The white gear is the one that will get driven by the two black ones.
The plastic plate will be used in the completed unit. The shaft supporting the white gear is a dummy just used for setting the tumbler gears in the right place.  The dummy shaft is 10 mm in diameter the same as the mill table leadcrew end. The tumbler gears shafts are 6 mm diameter just pressed into holes drilled into the plastic.




This is the white gear shown in the previous picture along with the mounting bush and retaining ring. It's yet to have the keyway machined into it.  The fastening screws are M3 countersunk.




This is the gear mounted on its bush.  The countersinks have not been done at this point although the holes have been de-burred.




This gear, part of a duplex one has been turned down so that its thickness is only as wide as the teeth. I machined both sides and drilled it to have an 8 mm bore which has a taper machined into it on the other side to fit the motor gearbox shaft.  The taper can just be seen in the picture.  This gear will drive one or the other of the tumbler gears.




Its shown here just placed on the motor gearbox shaft.  When its tightened down the splines will grip the bore and stop it slipping.




As can be seen there is not very much clearance between the gear and motor mounting plate. This is because this motor has a much shorter output shaft. When I did a trial assembly there was only one millimetre clearance between this plate and the top of the tumbler spindles.




This photograph shows the arrangement on the lathe that I used for slotting the 4 mm wide keyway into the bush for the gear.  The red handled screwdriver is a 2 mm Allen hex driver being used to adjust the depth of the cutter bit. The cutter bit is a 60 mm long square HSS tool bit with the end ground to an edge.  I made the hand slotter after having cut the keyways in the mill gears by traversing the lathe saddle back and forth.




And the finished slotted bush.  Surprisingly it was harder to cut in the brass than it was cutting steel.  Someone suggested that what I thought was brass was probably bronze.  Which might account for the difficulty ! 




Here it is trial fitted onto the mill table leadscrew.  It fits securely without any slop.  I'm quite pleased with it.

More Later:  Thanks for looking.


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## robcas631 (Jul 10, 2014)

Great job Baron!


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## BaronJ (Jul 10, 2014)

Hi Rob,

Thankyou !  Your encouragement is much appreciated.

This version the MK2, is a little more complex than the MK1.  I hadn't expected the size of the gears to make so much difference in controlling the tumbler mechanism.

More to come.

Thanks:


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## crankshafter (Jul 10, 2014)

gus said:


> Hi Baron,
> Please post working Video. I have one of these DC motors. Are your using a clutch too?
> 
> Power Table slide is number 1  on my hit list. Sick and tired of hand cranking.:rant:



Hi Gus.
I made a powerfeed for my mill-drill, i used 42V(I was runing it on 24v, plenty speed ) feedmotor out of a old wirewelder. Directly on the feedscrew with a dogclutch between. Used a PWM and potmeter to adjust the feed. Easy and simple. AND works like charm.woohoo1 No fiddling with gears and :redface2:*bang*
Reg.
CS


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## gus (Jul 10, 2014)

crankshafter said:


> Hi Gus.
> I made a powerfeed for my mill-drill, i used 42V(I was runing it on 24v, plenty speed ) feedmotor out of a old wirewelder. Directly on the feedscrew with a dogclutch between. Used a PWM and potmeter to adjust the feed. Easy and simple. AND works like charm.woohoo1 No fiddling with gears and :redface2:*bang*
> Reg.
> CS




Planning to DIY Mill table Power Feed. Bought a MIT aka made in Taiwan 30 years ago for the Bridgeport Mill in the plant. With the factorty shutdown,same went to the Rag& Boneman. MIT Power feed cost me US$1000. 

With the mini mill there are times when long pieces are milled. I can fall asleep milling long pieces with ten-------20 repeat cuts.:rant:

I have the speed controllers and motors from Ebay. After the Nemett-Lynx is up and spinning ,it will be mill upgrading.

Not been gear cutting after the last mitre gears for the Rupnow H&M Engine.
Some upgrading required for the DIY gear cutting equipment.


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## BaronJ (Jul 11, 2014)

Hi Guys,

Not too much to report today.





I've opened up the hole in the plastic plate and used the dummy mandrel to support it through the aluminium mounting plate.  This is fastened to the mill bed end with the leadscrew spindle coming through.  The tumbler operating lever is secured into an aluminium block secured into the plastic plate just behind the two black gears.  The operating lever is 6 mm diameter with an M5 threaded end.  This is screwed into the aluminium block.




The plastic block is intended to ride on the boss extending from the mill table end and is prevented from coming off by the large flat head screw to the left in the first picture and the bridge with the control lever running through it on the right.  The bridge is 13 mm high and 6 mm thick held by two M4 countersunk screws from the rear.  The aluminium block can just be seen underneath the two gears.  Its secured by heating it and pressing it into a machined slot in the plastic plate.  The plastic is too soft to provide a good threaded hole securing the control lever




The is a close up picture of the large flat headed screw that I made to prevent the plastic block from slipping off the mill table boss.  The screwdriver slot was made by hacksawing a slot across it.  The mark at one end is where I slipped a little when sawing it.  The holding thread is M6 with a nut and washer behind the mounting plate.






These last two pictures are just general views of the assembly.

I intend to cut teeth into the bridge so that I can make a dog clutch to prevent the tumbler from being pushed out of mesh.

More to come:
Comments welcome !
Thanks for looking.


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## BaronJ (Jul 12, 2014)

Hi Guys,

I got somewhat further today.  I've got the dog clutch finished and tested.







A couple of pictures of the business end of the dog clutch.  The whole thing is made from some bits of scrap brass tube and a damaged "N" type socket.  The dogs are turned down bits of a 2 mm diameter steel pin that I came across.  The brass tube is 1/4" bore.  I milled off two flats so that they were a loose fit into the slot in the piece of aluminium bar that the control lever passes through and soldered the collar made from the "N" socket on the end so that it fitted level with the slots. Afterwards I turned things down to size.




Having already found a suitable spring.  I then put the control lever and dog into the mill and cross drilled a 1.5 mm hole all the way through. Having removed the control lever I then milled a 3 mm long slot in each side of the dog tube.  The slotted fingers are not mine, they were already cut in the bit of tube.  I eventually turned them off.




This is when I milled out the three slots to take the dog pins.  That last slot looks a little rough. For some reason a corner chipped off the 2.5 mm slot drill.  However I used a file to finish off the slot.




This is a trial fit to make sure that the dog clutch fitted into each slot without jamming or riding.




Again a trial fitting of the spring and retaining pin.  Just to make sure that everything moved smoothly and didn't jam anywhere.  The retaining pin is a filed down bit of a used pop rivet shaft.  Its a nice fit into the 1.5 mm hole and retains the spring exactly.  It won't fall out if the spring pressure is removed.
The green pen marks are what I used to locate where I needed to put the control lever for each of the dog clutch positions.




This photograph shows all the bits used in construction of the dog clutch and its operating collar.  The piece of wood that they are sat on is 40 mm square so that it gives some indication of size.  The black operating collar is a short length of Acetyl plastic drilled through 1/4" with a hand turned finger grip near one end.  The other end was turned down to match the turned brass dog support at the other end.  The wires are 1 mm diameter spring steel.  I heated the end to red heat and pressed then into the Acetyl rod.  The other end was heated to red heat and bent through 90 degrees with 2.5 mm long legs on them.  You can see the 1 mm holes drilled into the brass dog support collar where they fit into.




This is the assembled clutch.  The wires hook into the holes and allow the dogs to be pulled back in order to clear the notches and allow the tumbler plate to be moved up or down.







This is a couple of views of the finished assembly complete with the end cap.  I just used a little super glue to secure it.  It really needs to have been about a millimetre longer or drilled in the end with a fastening screw.

Its just a matter of putting it all together now and making the speed controller.
For the time being I'm just using the variable voltage power supply to control the speed.  But that will be another thread.

All in all this has been an interesting exercise in what can be done with bits and pieces salvaged from various bits of scrap.  If I had to do this again I would have stuck with the original design but used larger gears to get the higher traverse speed.

Thanks for looking.


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