Member postings for AlanW

Brian,

I have acquired a variety of cutters over the years, some sharp but the majority in need of refreshing. Most have clearly had the flutes sharpened in a professional environment (because the diameters are undersize). With no T & C grinder and a reluctance to spend the required time to build one, I opted for Harold Hall's solution using a bog standard bench grinder. It is probably a bit tedious to set up for grinding the secondary clearance, a job best done in 'batches' but the principle works surprisingly well. See how simple it is here:

http://www.homews.co.uk/page121.html

Alan

Not so long ago, I bought a (very) cheap 1/2" NPT die on eBay from a source in China. It looked OK in the photograph but the one that eventually arrived had a dimple in the wrong place and no split. A couple of minutes with a diamond cut-off disk in a mini drill had it useable and it actually cut very well.

I only needed it for a one-off job, so it wasn't worth opening a dispute (especially over a fiver including postage). My thought is that someone is supplementing their meagre income by selling the contents of a factory scrap bin. It would make sense; if a dimple is out of place, why bother to complete the rest of the manufacturing processes.

Alan

Further to my last post, I made a couple of extended length spindles and spacers to allow larger gears to clear the idler spindle. I haven't tried many of the combinations but the new arrangement worked fine for 26 and 27tpi and also for a 30.5tpi screw for a Victorian sewing machine. With some combinations, it puts the last but one in the train in half mesh with the leadscrew gear, so I need to lok into solving that issue.

Thanks for your input folks.

Alan

Thanks Graham, all very useful. I didn't notice at first that intermediate pitches are generated, thinking that they were just different combinations for the same result.

If you have read my previous replies, you will have gathered that I need to make some changes to the lathe for quite a few of the gear combinations to work, owing to the lack of distance between the second gear on the top spindle and the idler gear retainer. Having given it more thought and seen Andrew's modifications, I will probably make new, slightly longer, spindles and spacers of around 3mm thick so that the second gear clears the end of the idler spindle completely. That should allow quite large gears to fit.

Woodworkforums.com has now let me download the calculator posted there but I haven't had a chance to try it out yet. Then again, thanks to you, I have a comprehensive list so I may not need to.

Thank you.

Alan

Hi Andrew,

An interesting collection of parts. Unfortunately the selectable idler would make no difference. The idler on the WM240 is clearly different from the C6; my idler is a nylon ring gear that is a sliding fit on the outside of an unshielded ball bearing. The large washer that baulks the outer gear on the top spindle probably serves the additional purposes of shielding the bearing AND preventing the gear from sliding off the bearing. More thought needed, I think. Thank you for your suggestions. In fairness to the lathe, most of the gears I am likely to cut will be metric and the lathe covers the range adequately. However there will be occasions when imperial will be needed. For example, last week I was able to cut a 1/4BSP (parallel, thankfully) which is 19tpi; I also needed to cut 1/4 and 3/8 NPT but the 18tpi is conspicuous in its absence. As it happened I chose to buy dies because I didn’t want the complication of cutting tapered threads on the lathe.

Brian,

Point taken. Rest assured, the Holy Grail is safe from me! I was actually too hastily referring to the solutions provided by Graham (all eight pages of them when pasted directly into Word). On closer inspection of the list, what I thought were multiple solutions are actually intermediate pitches as well.

Alan

Hi Graham,

I have measured my WM240 as you detailed and obtained the following:

a) Distance from feedscrew centre to bottom of 40T idler 152mm (150mm measured +2mm)

b) Distance from feedscrew centre to top of largest (90T) gear 185mm

c) Distance from feedscrew centre to lowest banjo lower spindle centre 39mm

d) Maximum size differential between gear diameters on top banjo spindle 8mm (52:60) *

e) Air gap between gears 1mm (boss on all gears except 25mm)

f) Spacer diameters 22mm

g) Maximum distance between upper and lower banjo spindle centres 100mm

h) Smallest size top banjo gear in mesh with 40T idler smallest gear (25mm)

* This distance seems disappointing when compared to the 20mm for your C6B and, reading down the top banjo spindle combinations, it looks as though quite a few selections would be prevented with the idler as is. The limitation is caused by the second gear fouling a large washer/cover plate over the idler gear bearing. More space could possibly be gained by replacing the ball race with either a plain or needle roller bearing. I tried several combinations of adjacent size gears but couldn't better the 8mm. 60:70 just rubs on the offending bearing cover, preventing complete meshing.

Other than the lack of gear size differential, most of the WM240 measurements are not vastly different to your C6B.

I appreciate the time you must have put into this for me. Thank you.

Alan

Thanks very much Graham and Andrew.

Wow! What a lot of combinations, just from the standard gears. Now to do a cull to the smallest % error. I wonder why the manufacturers won't give this sort of information to make life easier for their customers.

Graham, when I'm let free this afternoon, I'll measure the space as you so clearly explained in your post. I'll then get back to you if that is OK.

Many thanks

Alan

Graham,

I forgot to note in the earlier post that the leadscrew pitch, being a metric lathe, is 2mm. At least that is how I see it with the non-ganged gearing for 2mm pitch showing 40T on spindle and leadscrew.

Alan

Hi Graham,

That is a very kind offer. Thank you. I'm sure there are other 240 owners that would also be grateful for a list of extra threads.

The magic gear that is absent from the 240 range seems to be the '66'; bit of a cheapskate omission if it could provide such a range of other common thread pitches. (Anyone from Warco reading this?) The full set of gears I have includes: The resident 40T on the spindle plus 40T idler; the actual 'change gears are 25, 30, 33, 40, 42, 52, 60, 70, 75, 80, 90, 90.

Comparing your solution above for 24tpi to the standard gear set also shows that '50' is also not included. Both of the omitted gears are available from HPC in Mod 1 size at reasonable prices. The banjo size would also not be too much of a problem because a redesigned replacement would be simple to manufacture. I've been there before adding an extension to my Hobbymat banjo to extend the range. That, though, was simply to add a 30:60 or 35:70 cluster to double or halve existing threads.

I have tried to access the thread on Woodworkforums.com but ,even after registering, it won't allow access.

I look forward to seeing what your calculator comes up with.

Alan

Ian, I hope I haven't found this thread too late to receive a response. I bought a metric version of the Warco wM240 recently, only to find that it has some gaps in the tpi thread range. The more glaring omissions to me are 18 and 24tpi, used in the Unified and Whitworth ranges. I've tried on-line change gear calculators but haven't found any solutions that make any sense. With the WM240 having the same 40T spindle and idler gears, I wondered if your calculations for the C6 would apply, if I obtained the suitable extra gear(s).

The table for the WM240 is below.

Alan

Edited By JasonB on 17/07/2015 18:45:37

Alan,

I hope I'm not too late entering this discussion but I live near Boston and have a Hobbymat myself, so I could, and would, be willing to visit you to see if I can do anything to help.

Are you sure it is the leadscrew nut locked to the leadscrew or just that the backlash adjustment is too tight? Leadscrew backlash is taken up by screwing the handwheel onto the end of the leadscrew and locking the handwheel with the nut; it is quite easy to inadvertently tighten the handwheel a little more when tightening the nut - result, leadscrew wont turn (been there, got the T-shirt). Unless the leadscrew is rusty, which it shouldn't be if the lathe has been lubricated, I can't see how a bronze nut could become immovable.

I will email Neil a reminder of my contact details to pass on to you.

Another Alan

Does anyone know the purpose of the equipment, made by Zeiss, in the photo and how it was used? As can be seen in the photo, it is incomplete and the vacant stowage positions in the case suggest that at least one large and other smaller items are missing. I suspect that it is some kind of optical measuring equipment; when peering into the offset lense of the circular object at top left, a degree scale with vernier can be seen, backlit by a very small mirror. More photos in the Gallery under ‘Zeiss equipment’.

Thanks

AlanW

Edited By David Clark 1 on 05/02/2013 13:55:33