|Mark Four||28/04/2022 18:20:54|
|1 forum posts|
I have recently acquired a Boxford ME10 here in the States from a friend who knew almost nothing about it other than how to turn it on. The number stamped on the bed is Me10-a-73816 and it has the imperial lead screw.
Its a nice piece with the power crossfeed, gear box, and coolant pump, and doesn't appear to have been overly abused, but its got some problems.
First problem I've encountered is that someone has fitted a larger drive pulley and rubber belt to the countershaft, and now it is impossible to get the Spindle Drive belt tight enough to not slip when taking even moderate cuts. The sheet metal of the belt housing has already been shimmed up to clear the larger pully but its still not enough to get adequate tension. I have contacted Boxford and was informed that the correct pulley is no longer available and they don't have the drawings to even tell me what the correct sizes are so I could possibly have a pulley made. Does anyone know where I might find the correct pulley or even what size it should be?
The second issue I have seems to be with the 3 jaw chuck. I have .012-.013 runout 3" from the jaws. Putting an indicator on the spindle shows no runout, and indicating on the body of the chuck shows a little less than .001, but I've got a repeatable .012-.013 on multiple precision ground rods at 3". Measuring the rod with the jaw at 12 O'clock, Jaw 3 shows .000, Jaw 2 shows .011, and jaw 1 shows .009. I have completely disassembled, cleaned, and reassembled the chuck making sure the jaws were in their proper place. I got no change. I have checked for bearing issues by chucking a long rod and wiggling up and down with an indicator on the chuck body and got 0 movement.
I would be okay with having to replace the chuck but from what I've read I believe my spindle should be 1.5" 8tpi Whitworth and I have so far been unable to find a replacement or backplate.
The last issue I'm having is locating a steady rest that will fit the bed and work with the 10" swing.
|not done it yet||28/04/2022 22:02:47|
|6812 forum posts|
Someone else might know, but I would be simply measuring the gearing and comparing the spindle speeds in the specification to that currently expected, to find the % oversized the pully actually is. Armed with that info it is a simple matter of choosing/calculating the original pulley size.
If one has access to a rev counter, no physical pulley measurements would be required.
It is likely the pulleys were integer ratios or at least relatively simple ones.
Does that help, for you to help yourself?
|Clive Brown 1||28/04/2022 23:31:29|
|828 forum posts|
The ME10 was supplied with 2 different countershaft types. Both types have twin primary pulleys to give a total of 8 speeds. For the earlier type the larger pulley is 8.5" diameter and gives speeds of 200 to 650 rpm.with a UK 1440 rpm motor The faster range is double that.
The later design was more compact, ie smaller pulleys and an overall faster range of speeds. I don't offhand know the figures.
The spindle nose @1.5" x 8 tpi is a BSF standard, ie Whit form.
I think that your chuck is probably worn or damaged in some way.
Edited By Clive Brown 1 on 28/04/2022 23:32:12
6421 forum posts
The Boxford was based on a copy of the US made South Bend lathe so many parts may fit across and be easier to source in the US.
South Bend chuck thread is the same diameter and pitch but with 60 degree instead of the BS 55 degree profile. If it does not freely screw on to the Boxford spindle you can run a BS tap down it to make it right. Tracy Tools in the UK sells the taps I believe.
There are Boxford groups on Facebook and on groups.io with lots of info.
PS There is also a strong South Bend section in the Homeshop Machinist forum that may be helpful with sourcing compatable parts.
Edited By Hopper on 28/04/2022 23:49:34
Edited By Hopper on 29/04/2022 00:10:32
2436 forum posts
I have seen some who regrind the jaws in position. Not sure how successful it is though. I have a boxford backplate i think. It came with the Myford & only goes on a couple of threads before binding. When questioned i was told it would probably be a Boxford item. Shame we did live nearer as you could have had it.
|David George 1||29/04/2022 06:00:23|
1844 forum posts
I have ground chuck jaws with great results but you need a grinder to fit to the toolpost and a cloverleaf plate, easily made, to do a good job. This is a video of grinding a self centering 4 jaw chuck but the same for a 3 jaw chuck you just need a 3 hole clover leaf plate.
|Speedy Builder5||29/04/2022 06:55:36|
|2615 forum posts|
Just an observation, should the cloverleaf, ring or whatever be located on the tips of the jaws (as per video) or as close to the chuck as possible. During the life of the chuck, the jaws will wear in their slots making them appear "bell mouthed"
Steviegtr, it may be a Southbend backplate which had the 60 degree thread instead of the 55 whit worth form.
|Thor 🇳🇴||29/04/2022 07:06:20|
1632 forum posts
6421 forum posts
It makes no difference. As long as the clover leaf plate is outboard of the chuck body, the end result is the outer tips of the jaws are pushed outwards during grinding, as if they were clamping a job. This results in the jaws being ground parallel in the (worn) working position. But probably the closer to the ends of the jaws the better I suppose. But due to the steps on the chuck jaws the clover leaf will only go on this far anyway.
The same result can be achieved by three equally sized pieces of flat bar being nipped up between the cheeks of the jaws, but is fiddlier to do..I have seen pics of it done with the pieces of flat bar hard up against the chuck body and reports are that it works satisfactorily.
Edited By Hopper on 29/04/2022 07:10:48
|not done it yet||29/04/2022 09:27:59|
|6812 forum posts|
If the chuck screws on, it is OK. The treads are to keep it tight but the location is by the register surfaces.
One may find that moving the jaws round by one slot, or two, will improve the run-out. Regrinding may improve things but possibly only very good at the particular diameter it was reground.
Modern chucks can be very good at a reasonable cost, but if the chuck actually grips the items OK, why bother? A three jaw chuck (any scroll type, actually) nearly always has some run-out and the usual modus operandum is never to remove the item being machined until all concentic surfaces have been cut. Replacing a previously turned item to a three jaw chuck will not centralise the item as it was originally - full stop! That is what an independent 4 jaw chuck is for.
If you want concentricity and easy removal and replacement of the item, turning between centres is the way to go.
Edited By not done it yet on 29/04/2022 09:29:13
|Dave Halford||29/04/2022 10:34:34|
|2054 forum posts|
I use a Boxford backplate on my Rockwell Delta 10"
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