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Member postings for Keith Long

Here is a list of all the postings Keith Long has made in our forums. Click on a thread name to jump to the thread.

Thread: Precision Ground Rod
08/08/2019 13:33:38

Vic try "Ondrives" - link - looks like they can offer a choice of stainless steel specs as well.

Keith

Thread: What size milling tool
06/08/2019 16:43:56

Garry, in the"Model Engineers Handbook" by "Tubal Cain" (T D Walshaw) for profiling with an end mill he states that the best results are when the cutter - diameter D is cutting a vertical depth (plate thickness ) of D and a maximum width of cut into the material of D/4. He also suggest that the minimum vertical depth of cut should be 0.006" and the maximum width of cut should be no more than engages 2 teeth on the cutter. The cutter diameter that you will use is more determined by what the mill can cope with in terms of power ,speed and rigidity. I've just been profiling 2 steel plates 6mm thick, stacked on top of each other (12mm total thickness) so that they came out the same sizes and my small mill was happy with 3mm passes (vertical height) and 1mm width of cut at 1000 rpm using a 6mm dia, 3 flute carbide cutter.

Keith

Thread: Locking Levers
05/08/2019 12:47:00

The levers originally linked to are actually made of zinc with stainless steel thread inserts - you have to read the full information, the heading is misleading.

05/08/2019 09:35:18

Vic, use "Bristol locking levers" as a search term on t'internet. Lots of them about in all sorts of materials at all sorts of prices from about £2.50 each and up.

Keith

Thread: Engineers blue alternatives
16/07/2019 11:52:03

Seems to me that folk here are confusing two totally different products. One "engineers blue" or "layout blue", which dries to a film that them can be scribed through so that layout marks show up, and "micrometer blue" which is a greasy blue paste, doesn't dry as far as I know but remains as a greasy blue film, and which is used to determine fits between mating surfaces and in scraping. The latter would be of no use for marking out as it will rub off very easily (if messily), while the layout blue (or felt tip pen) can be used to find interference between parts as well as used for marking out.

Thread: Dickson type T00 toolholders
25/06/2019 09:16:16
Posted by Terry olds on 25/06/2019 08:53:16:

does this help

Name:

Lynam Engineering Ltd

Office Address:

Leofric House Binley Road CV3 1JN Coventry

As there was a winding up order made on 03/04/19 I don't think you'll have much success in trying to contact them.

Thread: Why a round bed?
10/06/2019 15:10:02

I find that I use insert tooling quite a bit on my Drummond roundbed, so don't dismiss it too readily, and yes they are HEAVY. A bare roundbed ie just the lathe without drip tray, motor or stand is about 50kg, definitely not one for carrying upstairs single handed. If you look at the long bed version (an extra foot in length) then the drip tray for that alone is well above any weight you want to carry.

Thread: Boxford AUD needing a new Motor
30/05/2019 10:35:30

Pete just do an internet search for "V" belt pulley suppliers, dozens of them about, all selling pulleys off the shelf. Most these days are designed for use with taper lock hubs which you select to suit the motor shaft.

Thread: Questions: Myford ML 10
31/01/2019 18:47:35

"Single tooth dog clutch" is the important point of definition Mick

Yes but the clutch needs to be at the input end of the screw-cutting gear chain not at the output end to the lead screw.

Thread: Drummond parts
30/01/2019 14:47:21

Ian, yes there is, the M type is a well respected lathe. You might do better to join the Yahoo Drummond and users group as folk on there are always looking for bits to keep their machines running.

Keith

Thread: Copper tube wall thickness & pressure withstood.
12/01/2019 15:43:58

If you download the publication in this https://www.copper.org/publications/pub_list/pdf/copper_tube_handbook.pdf it will probably give you all the information that you need as well as a load more that you didn't know that you wanted.

Thread: Reverse Sewing Machine Motor?
10/01/2019 17:40:39

Most likely NOT reversible from experience. The motor that I bought in the last 3 years or so has offset brushes so is optimised for single direction operation. Also to get at the connections for the brushes or the coil would have needed some serious surgery to moulded plastic parts. The motors are sold as unidirectional but you can get either clockwise or anti clockwise versions. I sourced my motor from a sewing machine and spares supplier via EBay and bought the uprated (100 watt) version rather than the normal 60/70 watt type.

Thread: Part built Allchin 1.5 inch
08/01/2019 12:39:22

Just a thought after reading this thread that might help Derek.

As you've now got to machine a liner from scratch, would it be feasible to machine the cylinder casting right through at the bore of the designed annular space, and then machine the liner with ends that fit the larger bore but with the centre part waisted down a bit to make the annular steam space. Having a uniform bore through the cylinder casting would be easier than trying to machine the recess and machining the liner od down locally is just straightforward turning.

Thread: Nylon for axle boxes ?
06/01/2019 14:45:13

Pete the data in the spring table gives you the following.

OD - simply the outside diameter of the wound spring, the Free Length is the overall length (or height if it's vertical) of the wound spring just sitting there with no load on it. The Max solid length is the length of the fully compressed spring with all it coils touching - "coli bound". It won't get any shorter and it won't fit into a smaller space. The Lb/in is the "spring rate" ie how much load you'd have to apply to shorten the spring by 1 inch. So the "load for full compression" is the maximum load that any of those springs will support when JUST fully compressed. Taking the first line the difference between the free length and the max solid length is 0.75-0.3 inch or 0.45 inch. Now the spring rate in 21 lbs/in so 0.45 x 21lbs give you the 9.45 lbs that the spring will need for full compression - and still be a spring. If you loaded that particular spring up beyond 9.45lbs it would still support that load but would in effect be a solid tube with no spring in it until the load dropped below the 9.45lbs at which point it would start to extend again.

From that table you can work out what length any of those springs would be at a given load and then you can see which of them will fit your application or conversely how much room you need to allow in order to be able to fit springs.

Another point to bear in mind is that for springs used in parallel (side by side) you add the individual spring rates to get the overall rate, for springs used in series (end to end) things get more complicated and you have to use

(R1 x R2)/(R1+R2) to get the effective rate where R1 and R2 are the spring rates of the separate springs. The overall effect of springs in series is that the net spring rate is lower than that of either of the individual springs

Keith

Thread: Rocket design
05/01/2019 10:43:45

Fizzy if you do a google search on "Stephenson's Rocket, history" you should find a Wikipedia page about the Rocket. Part way down is a heading "modifications". According to "The Engineer" publication at that time, 12 months after the Rainhill trials Rocket had been modified so much that it looked like a different locomotive - with near horizontal cylinders.

Thread: Denham lathe
11/11/2018 16:22:44

Michael

Just to save you a bit of frustration, the common change wheels for Drummond lathes are 14 DP NOT 16 DP so you could have problems fitting them to your Denham, depending just how much room there is for gears.

Keith (multiple Drummond lathe owner)

Thread: Drummond round bed lathe - belt removal
29/10/2018 11:16:03

Hi Peter,

I guess what's stopping the shaft coming out is the collar that you've removed the screws "A" from - it's threaded onto the shaft! It's the collar used for removing end play in the spindle and acts to pull the spindle towards the rear bearing to adjust the end float. It's a normal right hand thread - quite fine pitch about 20 tpi I think - but if the grub screws are out it should unscrew quite easily. If it hasn't been adjusted for some time you might need to use a bit of rod as a tommy bar into one of the grub screw holes to get it started. The other thing to check is that the pulley can rotate on the shaft now that the long grub screw is out. There is no key there so the pulley should turn fairly easily. If it doesn't have a look down the hole in the pulley, there might be a second grub screw down there, 2 screws down the same hole is a common method of locking the first screw in place so that it doesn't work loose. You won't be the first to be caught by that and you certainly won't be the last - guess how I know!

The other possibility is that there is a burr on the main spindle caused by the grub screw in the pulley. The nose of the grub screw should enter into a dimple on the spindle to prevent that. If in the past it's been tightened onto a plain part of the shaft then it could have raised a burr. If you look down the grub screw hole you should be able to see the shaft and check that. If there is a burr then removing it before resorting to force to get the shaft out would be preferable, but access down the hole would be difficult. If you need to do that them a small circle of wet and dry stuck to the end of a rod or dowel might work for polishing the shaft locally - it isn't hardened so is quite "workable". I don't think there should be any problems due to wear ridges on the shaft, the spindles that I've seen show some scoring in the bearing areas but nothing significant otherwise. If wear was an issue you'd feel it with the bearing being slack.

Do you need to remove grub screws B and E - YES - and leave them out!! Those holes are for oiling the bearings and you definitely don't want a permanent screw in there to stop the oil getting through. On my round bed lathes those holes are generally plain NOT threaded. If I was screwing anything into either of those holes it would be an oil cup to help with lubrication or a knurled thumb screw to keep debris out. A plain shanked cap would be just as good. The bearings run on a total loss system so you need to be able to add a few drops of oil a regular intervals as you work - it doesn't need a lot - but having to remove grub screws to top up would be a significant disincentive for me!

Good to hear that you got the back plate off - you're getting there.

It would be worth you having a look at - and joining - the Yahoo Drummond lathe Owners and Users group. There is a stack of useful information there and a sizeable body of Drummond owning enthusiasts who can help with queries etc.

Good luck

Keith

27/10/2018 19:16:45

Hi Peter, assuming the lathe hasn't been altered in the past, then yes it's a standard right hand 3/4 inch BSW thread. It's probably stuck due to oxidised oil varnish or in the worst case a bit of rust. You won't do any harm by using a hot air blower (paint removing type) on the flange, warming it may soften the hardened oil. If your changing the belt anyway then use that as a strap wrench to get extra purchase on the pulley, you could also bolt a bar of some sort across the backplate to give you extra leverage. I see your lathe has the later type of integral cast iron bearing, the pinch screws are the big slot headed ones, back those off to give a bit more clearance for withdrawing the spindle. If you cant shift the back plate in situ, the spindle will come out along the bed towards the tail stock and you could then work on freeing the back plate in the vice.

Keith

27/10/2018 17:53:04

Peter if your round bed is standard the the chuck back plate unscrews from the spindle - it's a 3/4 inch, 10 tpi (BSW) thread - unless in the passage of time someone has changed it. The 3 step pulley is secured to the spindle by a grub screw in the smallest diameter pulley. Undo that and the pulley should then turn on the spindle. Slacken off the pinch bolts on the bearings , remove any collars, gears or spacers from the left hand end of the spindle, and the spindle should come out, either towards the tail stock or in the opposite direction. It's not fussy, the spindle is a constant diameter so can go either way. Look out for the thrust washer that fits between the pulley and the left hand bearing. That can be a bit of a fiddle to put back in but a bit of 1 inch bar popped into the left hand bearing while you slide the spindle back in from over the bed makes things a lot easier.

On my round bed the belt is joined with a "crocodile" or "alligator" clip (different trade names for the same thing) and I can just remove the coupling pin and take the belt off. You have to put up with the "click - click" noise as the lathe runs - I find it quite soothing actually!

HTH

Keith

Thread: Myford Super 7 metric change gears
15/08/2018 15:27:31

Martin - for occasional use or in en emergency then you'd probably get away with running 14.5 and 20 deg pa gears meshed but running a pair like that together by hand you can definitely feel the "notchiness" as each tooth engages and disengages. I'm pretty sure that at some point the teeth are actually a slight interference fit the the tooth space on the mating gear. I suspect that they would pretty soon both wear together and become effectively an "intermediate" pressure angle. My feeling is that the "notchiness" could lead to poor surface finish on the job.

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