Member postings for Tony Ray

Carl,

I can recommend the Ivan Law book having used the info within to cut 18 DP gears for a Boxford.

I made an arbour to hold the blanks - turning a section of the blank to make a shaft would waste a lot of material especially in the larger sizes - an 84T 1.5 MOD wheel is approx. 130m in dia. These are better made out of sheet material.

I too have an M250 and have looked at this very issue (yes I'm on the Yahoo group)

On the subject of material I really would not use delrin; Tufnol or aluminium will prove to be far more durable and these are readily available in sheet form. I have cut gears in both using my SX3 mill without difficulty.

Whilst it is possible to make single point cutters using the method in the book ( and I have for another application) I opted for buying Brown & Sharpe cutters but you will need more than one to cover the 30 - 92 Tooth range of the imperial conversion set.

As you already know the standard of fit of the 6 spline is very high. Keyway broaching 6 splines getting them to within 2 thou will be a challenge - you will have to find a way of ensuring the bush and broach are accurately indexed. If it were me I would build a slotting device. I looked at the Hemmingway kit but thought that it was a bit on the small side for cutting that many keyways in e.g. steel. Something based on a lathe tailstock casting might be more robust.

My conclusions were that if I could find a reliable method of cutting the splines I would opt for buying ready-made gears wherever possible. They are available in Hostaform -acetal (yes that's Delrin) and steel and the typical stock thicknesses can be reduced. This is one of the cheapest sources:

**LINK**

An alternative idea I had to the spline issue is to make up a splined inner bush that could be moved from one gear to another to cut down on the number to be cut. I also think that it might just be possible to 3D print the spline as an insert and bond that into the centre of a premade gear, or to resin cast them from a master spline

You probably also know that the splined section of the shafts on the M250 are bushes held in place with shear pins. If you removed the bushes you could replace them with simple keywayed bushes and then your gears could have one simple keyway.

It has to be said that however elegant the 6 spline arrangement is overkill in this application.

In the end I was offered an imperial conversion set. I swallowed hard & parted with the required sum but I think I would recover the cost if I ever wanted to sell them. Interestingly like Andrew some of my original gears are Tufnol but the conversion set is all steel.

Do also post your progress in the Yahoo forum as it will be of interest - these 6 spline gears sets are rare and getting them made is costly.

Tony

Given that endmills & slot drills have standardised shank diameters -either imperial or metric what is the purpose of R8 collets that fall between these sizes ?

As R8 only seem to be used in milling machines for tool holding I can't work ot why they would be needed - but there will be a reason.

Tony

End Note:

Well I made a button tool and it worked beautifully. I didn't harden the button I superglued it in place before i remebered that i was going to. Anyway on alloy it has not shown any wear.

What would i do differently ? Spend more time thinking about the setup to get a better blend between the angled flanks and the radius at the bottom of the groove.

Its useful to know that a flat bottom groove would work too. I'm sure the baler application is a lot more demanding than mine.

Cheers

Tony

Gents,

Thanks I'll follow the button cutter route & use loctite as I'm not equipped to braze - though I could soft solder it ..

Off to the workshop !

Richard,

As a restoration project I'm all for it. As a Drummond owner (1908) I'd say the biggest drawback is the lack of a through bore. I would'nt want to have to rely on the Drummond alone although many engineers have built great stuff on very limited machines.

It's all about budget and what you want to do. When asked about 'What do you do with all of those machines?" I reply "

"I make things to make things. When I have made those things I use them to make more things that help me to make things"

Tony

Morning,

I'm making sheaves (pulleys) to carry 3mm wire rope in ally for a counterweight system. At the bottom of the groove i need a radius of 1.7mm (please don't quibble the design). Is there any alternative to grinding a form tool by eye ? I'll machine the flanks before putting in the groove.

Thanks

Paul,

Where are you based ? Perhap you might be lucky to find an adult education class near you offering metalwork. The one I attended in Eastleigh allows for turning milling and welding. You will learn so much faster with someone showing you the ropes.

I chose R8 on my mill - I have both R8 collets and an ER32 system on an R8 arbor but the R8 collets are so much faster to change.

CAD - down load Draftsight - its free and as easy to use as any of them once you have got your head around it - there is a Workshop Practise book - but I don't know if its any good - perhaps someone else can comment on it ?

Tony

John,

Any spline info you could contribute would be most gratefully received.

Pehaps you'd better get back before Obama & Putin fall out completely !

Tony

Steve,

Thaks for the dimensions. There may be other metric standards but it doesn't appear be this one:

BS 5686:1986, ISO 14-1982: Specification for straight-sided splines for cylindrical shaft

an excerpt is here

http://www.roymech.co.uk/Useful_Tables/Keyways/Spline.html

Unfortnately standards in general are not freely available. It would seem a bit crazy if it isn't based on some standard.

I'm seriously considering trying to pull changewheel data together for the most popular lathes & publishing it to the web - perhaps Tony Griffiths would put it on his lathes.co.uk site ?

Tony

Good idea Mark.

If it helps anyone the M300 M250 spline is 6 off 1/4" straight sided splines major diameter 1" the spline height is about 0.051".

There is plenty of info on metric ISo splines but I could not access any BS standard for imperial splines on the 'net. Does anyone know if the above configuration relates to a standard ?

and if so what ?

Thanks

Tony

My AUD also runs a little slow in the higher speed ranges when its very cold - you can hear it increase in rpm as it warms up.

Check also that neither of the drivebelts is slipping as they might not grip as well when cold. In my case when I had slippage it could bot be heard, I identified it by a little heat build up on the affected pulley but I think a dot of marker pen on the belt an pulley would also work.

Tony

Steve,

Is this type of spline common ? - Splined gears were used on Colchesters; Bantams are 8 splined and DP and the Harrison M250 and M300 are 6 splines like yours but 1.5 MOD.

It seem to me that the splines were as much a way of tying users in to OEM rather than buying stock gears and cutting a simple keyway

I was not impressed by Boxfords complete unwillingness to share a simple fact about the module - I also asked about the spline as I had hoped that the gears it would be compatible with my Harrison.

Everyone knows that the older Boxford are 18DP 14 1/2 PA (or can find out in a couple of clicks).

I'm going to post your MOD info on the Boxford Yahoo forum so it becomes more widely available.

Tony

Les,

I had but thought that getting the correct belt could be tricky. I have used a toothed belt on the spindle drive.

Micahel - that tensioner idea is clever.

Hope to start on the cable drive inthe next few days.

Tony

Gents,

Many thanks for the advice. I don't think the Woodward design included a spring tensioner but I like that idea. I will try the grooves as per the clock barrel and I was only thinking of a few turns.

Confesion time. I too have a rack & pinion and although its a bit ugly ( probably 16 DP) it worked. However in installing an 18mm tube carrying thrust bearings & brass bushes for the Y axis there is insufficient clearance to refit the rack - Doh! - although I could relieve the tube to obtain the required clearance. I too however like the cable idea so will give that a go first.

When I bought my Stent it looked like it was in need of a bit of TLC but this has turned into a complete rebuild. It seems to me that either it has had two owners, one with good machining skills and the other not so much or one owner who was good at turning and pretty lousy at milling. I do wonder sometimes if I would have been better starting from scratch, though I'm hoping that I will gain some time as I don't have to make the support fingers.

Anyway Norman I'll let you know how the cable drive works out.

Tony

I'm still working on my Stent restoration based on Charles Woodward’s article in MEW 2008. I have implemented the rotating captive z axis nut Fig 3 and the y axis lead screw Fig. 4 Pg. 34.

He also describes a cable operated X axis as an alternative to the rack & pinion. I can't quite see from photo 8 pg. 33 how the pulley is arranged. The questions I have are:

1. How might he cable be anchored to the drive pulley by the grub screw without having a nasty kink as it winds onto the pulley?

2. I believe the pulley is grooved. If it requires more than one turn of wire around it as seems likely due to the travel required, how is that groove arranged? I.e. would it be cut like a thread at a pitch that exceeds the wire diameter?

Has anyone made this modification? If anyone has a sketch or a picture of such an arrangement I would be most grateful.

Many thanks

Tony

Jarek,

'Turn for grind' does not make any sense on its own, perhaps you are reading something that was e.g. translated from e.g. Chinese ?

Turn is probably from the verb turning ie. to remove metal using a lathe.

Grind in this is probably from the verb grinding i.e to remove metal by ginding eg as done by a cylindical grinder.

if you could reply with thefull paragraph from where you have taken 'turn for grind ' I might be able to work it out for you.

Tony

Hi,

Thanks to all who contibuted. I will go with the top hat solution. Luckily once the mating parts are in place the repairs will not be visible. I have no access to helicoils nor experience and unfortunately the existing holes are so far out that realignment and tapping thru the 3/16 to M5 is not possible either. However these are good solutions & I will bear them in mind for future corrections.

Thanks also to Michael for the links to the Stent articles. I am incorporating some of the modifications described by Charles Woodward in MEW. I have the Z axis completed and will soon start on the Y axis. My mods also incorporate metrication.

Tony

Chris,

I have an Sieg SX3 with an R8 spindle I have a set of R8 collets and an R8 ER32 collet chuck. I started off using the ER 32 but soon found that for me working with R8 collets is so much easier. They grip up with far less tightening effort and release easily too. I fitted a spindle lock to the mill which makes the whole thing so much easier. The ER32's do come in useful but they mainly get used on my lathe.

Tony

Hi,

I am looking for advice on filling 4 tapped through holes in cast iron.

I am renovating a Stent T&C grinder, some of which is built really well but other parts have misaligned and drunken tapped holes. Once I have filled the holes I will need to tap new ones within the filled areas. I envisage boring (method unknown) out the existing 3/16" BSF holes to a diameter that will more than encompass the M5 replacements so that all of the new threading is within the plugs.

Do I

1. press fit some MS plugs

2 push fit and retain some ms plugs

3 countersink either side of the plate and fit the plugs as rivets

4. tap eg M10 and retain the threaded plugs

Once in place I'll flush them with the existing surface

I can fill them with weld etc as this would probably distort the casting which is surface ground.

All ideas gratefully received

Tony

Jason,

Yup, that's about it.

Thanks also to Dias - I have found two interesting articles in the Digital Archive of MEW:

Surface Finish on Metals MEW July/August '97

The Appropriate Finish for Tools and Workshop Equipment MEW August '99

Just need to practise now !