Milling machine Y axis

[DEREK SPEDDING 1Participant @derekspedding1]

I have a Hobbymat milling machine that i obtained about 20 years ago. Done loads of mods on it and it works fine for what I need it for.

The only thing that has hacked me off is that the Y axis motion is in the opposite direction to what I would say is normal. I have not used a miller since I was an apprentice almost 50 years ago.

Can I ask what is the norm for them. On the Hobbymat turning the feed handle clockwise moves the table outwards toward the operator which is opposite to normal lathe convention.

Things came to a head the other day when I scrapped an casting so I ordered a Y axis leadscrew that fit a Sieg mill.intending to doctor it to fit the hobbymat thinking it would be a left hand thread. It arrived today and that is also a right hand thread. I am beging to think I am loosing it.

So can anyone tell me what direction the table moves when turning the handle clockwise.

Thanks

Derek

[DEREK SPEDDING 1Participant @derekspedding1]

[RobCoxParticipant @robcox]

I think my SX2 has a left hand thread on the Y axis. The DRO is set up so that the tool moving away from the operator relative to the workpiece, ie workpiece moving towards the operator, is a movement in the positive direction. To achieve this the handle is rotated counterclockwise – that I think makes it a left handed feed screw.

The littlemachineshop website indicates that x axis nuts are RH and y axis LH for the X2, so that seems to confirm this.

Your Hobbymat would appear to have a RH feedscrew – opposite to the Sieg.

Rob

[Peter KroghParticipant @peterkrogh76576]

I have never seen a mill, or lathe, where turning the handle clockwise moves the table towards the operator.

Pete

[Michael GilliganParticipant @michaelgilligan61133]

It depends how the nut and screw are configured

• If the screw winds into a fixed nut, then RH thread will produce the 'natural' movenent.
• If the screw is in bearings at each end, and the nut 'rides' it, then LH thread gives the 'natural' movement.

A diagram or photo of the Hobbymat slide would be useful.

MichaelG.

[colin hawesParticipant @colinhawes85982]

It is normal to have a left hand thread on machine tool's X and Y axes so that clockwise rotation moves the table away from you. Colin

[Neil WyattModerator @neilwyatt]

The hand of the leadscrew depends on whether the nut or the handle is fixed to the moving part.

For example on the X2 the Y handle is fixed to the base, the X handle is attached to the table.

Neil

[DEREK SPEDDING 1Participant @derekspedding1]

Thanks Chaps. Its all clear now why the new leadscrew I bought is no use. My table is configured with the nut riding on the screw and the screw is in bearings at each end. I had expected to be supplied with a LH screw.

The Hobbymat has been built with a RH thread for some reason. I should have dealt with this years ago as going from turning something on the lathe and then using the mill I had to think twice which direction i turned the handle.

Been looking without success now for a LH screw 2mm pitch 12 or 14 mm Dia. Its looking like I am going to have to make one myself.

Thanks

Again.

Derek

[ManofkentParticipant @manofkent]

All rather strange. I have a Hobbymat mill and have just checked. Turn the Y axis handle clockwise and it moves in towards the column.

Mine is based on the BFE 65 head.

John

[JonParticipant @jon]

Seen it a few times on home made tools but never any commercial item.

Derek just re arrange the leadscrew and nut/s
Must have a fixed nut in centre presume RH thread. Only need fixing lead screw to one end of table to via a bearing and adjustability. This pushes table then clockwise from the right and anti clockwise table towards you.
Better with two bearings either end of table with adjustability to take end play out of screw. Both ends will then push and pull depending upon direction.

[Michael GilliganParticipant @michaelgilligan61133]

Derek,

Try looking at Marchant Dice : **LINK**

http://www.worldofcnc.com/collections/trapezoidal

They sell very reasonably priced Trapezoidal leadscrew 'by the 100mm'

Link above is to the web-shop, but they also list on ebay.

MichaelG.

[DEREK SPEDDING 1Participant @derekspedding1]

I can only assume that the table was one of the first they built and corrected the problem on later ones.

Tried to link to a video that I took just to prove Im not going crazy but was unable to create the link on here.

However Jons idea sounds interesting, I will give it some thought. but will entail building out the travelling bed by about 6" . Humm.

The other thing I had been toying with was to offset the handwheel and add 2 gears. This would automatically reverse the operation but would add more backlash and probably loose a bit of "feel".

Will post back when I resolve it.

Derek

[DEREK SPEDDING 1Participant @derekspedding1]

Thanks for that. . Helical gears are a good idea , an improvement on what I was thinking of. Can anyone point me at a good source?

[duncan webster 1Participant @duncanwebster1]

If it has a large number of teeth I reckon straight gears would be OK, but remember that if you move the graduated dial it will be reading the wrong way (or perhaps it reads the wrong way now!)

For suppliers look at HPC in Chestefield **LINK** or Reliance gears in Huddersfield **LINK**

I've used both in the past an been well satisfied. Second hand change wheels would be cheaper

[Neil LickfoldParticipant @neillickfold44316]

It all depends on the Mill. Some have LH leadscrews and some have RH leads screws. Neither is wrong. I have seen geared cross slides on mills, where it is 1:1 and then 10:1 to get the precision. A lot of machines with Ballscrews with a clockwise handle turn brings the table to the operator, so the cutter is effectively in the plus direction from the operator. Similar on the LH end of the mill, a CW handle movement is the Cutter effectively in the positive direction.

Neil

[DEREK SPEDDING 1Participant @derekspedding1]

Thanks for all the advice. After carefull thought I took the path of least resistance and went for the gear option.

I had some 40mm dia fine tooth gears from a big industrial stapler taken of a printing machine.. I built a gearbox using shafts running in ballraces.. Just finished it today and it works a treat.

Should have done this years ago..

Derek

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