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Member postings for DC31k

Here is a list of all the postings DC31k has made in our forums. Click on a thread name to jump to the thread.

Thread: clarkson autolock 3mt
05/04/2020 17:26:36

I have always been under the impression that Clarkson made Autolock chucks in three sizes, small, medium and large.

I cannot remember the size range but someone might have a Clarkson brochure somewhere.

You should be able to find a medium in 3MT, but are unlikely to find a large. The medium ones are quite rare.

If you do find one, check it for runout as the medium ones can be too much cutter for the size of the shank. I had an R8 medium one that had suffered this. I gave it someone and he did manage to straighten it.

Thread: Gear Cutting - Pressure angle.
05/04/2020 13:07:34
Posted by Bazyle on 05/04/2020 11:20:55:

If one can make a gear with this method, however many facets it end up with, one must be able to make the 'inverse' an involute cutter by the same principle. But how?

There is some difficulty in your request. The method shown cuts the gaps between the teeth. The cutter you want is the shape of the gaps between the teeth. The bit you want to save is the bit that is ending up as swarf.

If you have a look at Fellows gear shapers, the cutters resemble a spur gear, so you might be able to make something like one of those, but the machine to drive that style of cutter is somewhat specialised.

Thread: Another mystery no. 100
05/04/2020 12:58:46
Posted by Ian Reid on 05/04/2020 12:14:04:

If anyone has the Instruction sheet Adrian mentions I would like a copy if it could be loaded onto this site.

Post number 7 here:

https://mb.nawcc.org/threads/gear-cutter.152949/

Thread: All things Beaver Mill
05/04/2020 09:50:48

Mike,

I have sent you a private message.

Alf,

There are two pins, one for 'swivel' and one for 'nod'.

They are both standard imperial taper pin specification of 1:48 on diameter.

Threads are unlikely to be Whitworth form given that the nut that fits on the pin is 9/16" A/F and the rest of the machine uses UNC/UNF fasteners.

Thread: Gear Cutting - Pressure angle.
04/04/2020 21:19:30
Posted by Steve Crow on 03/04/2020 17:32:51:

Making single point cutters of that size sounds tricky and I don't have access to a grinder. This seems a relatively simple way to make a cutter.

The other good thing about a generating method as opposed to a form cutting method is that you can profile shift the gears if necessary. Again, lots of info. at a digestible level on khkgears' site.

I do not know if you have or want CNC facilities, but if you do, a look at Gearotic might give you some options.

Thread: How can I use this motor economically?
04/04/2020 21:05:19

Deep inside the SIM card in my head, there is something that says the LinuxCNC people, before the days it was called LinuxCNC, were developing an open source servo motor driver.

Unfortunately, that is all I know.

Thread: Small drill bit in large drill press?
03/04/2020 08:07:12
Posted by Martin Kyte on 02/04/2020 22:30:41:

Easy enough to make in the lathe short stub of steel, carefully drill a suitable sized hole down the middle ensuring the drill is started exactly central. turn the out side at the same setting. Hold the 2mm drill in the tailstock to ensure alignment and loctite the two together.

But this assumes that he has not only a lathe but a means to hold the 2mm drill to make the hole in the sleeve.

And the problem we are trying to solve is how to hold a 2mm drill in the first place...

ArcEuroTrade are currently shut so suggestions to buy from there are rather pointless.

Drill chucks with straight shanks are surprisingly difficult to find, and even more so in small sizes. Many chucks, many straight shank arbors but the two together are thin on the ground.

The pin chuck is a good idea, the most important part of which is that it has a straight, short shank. There are many things (wrongly) described both as pin chucks or pin vices, a lot of which have long, knurled shanks.

Given the OP says he is new to the game, a little appreciation of his situation and links saying 'buy this, it will solve your problem' would be more helpful.

Thread: Cutting long tapers using homemade top/compound slide
02/04/2020 20:45:17

Sorry to follow up so soon, but it might be worth perusing this thread:

https://www.model-engineer.co.uk/forums/postings.asp?th=110851

Our very own Jason makes some very relevant points that will greatly assist your situation.

02/04/2020 20:35:04

How accurate does the taper need to be? A great deal of the complexity of a full-blown taper attachment is in the adjustment mechanism. If you do not need such fine control of the angle, a much simplified version is reasonably easy to make. It would be more like a copy turning attachment where the pattern is straight-edged.

I would use some of the cheap round rail and bearing/slider that you see on low end CNC machines. Glue it to the back of the bed, set the angle good enough, disconnect the cross-slide feedscrew and have at it. Put on the cut with the compound slide.

Even simpler is just to spring load the cross slide against a straight piece of flat bar set at the correct angle. You might be able to set up the straight bar such that it is clamped to the bed just above the cross slide and let the non-moving part of the compound ride along it.

Thread: Alexander/Deckel Mill
02/04/2020 20:20:37

Is this like an FP1?

http://modelengineeringnorge.weebly.com/deckel-fp1-riser.html

Thread: Gear Cutting - Pressure angle.
01/04/2020 19:58:27
Posted by AdrianR on 01/04/2020 18:00:03:

From what I can see on helicron this method creates an approximation to the involute curve by cutting a number of facets on each tooth.

The method is one well-recognised in industry and is by no means an approximation. It is a method of _generating_ gear teeth, the same as hobbing or gear shaping. Have a look for Sunderland gear planer. There are a few posts on this forum by John Stevenson that have discussed the method. There are numerous books available on the internet archive that discuss generation methods.

01/04/2020 17:54:45

My goto online reference for all things gearing, at KHK Gears says z=2/sin^2(a) where is tooth count and a is pressure angle is what determines minimum teeth for no undercut when using a rack-type cutter.

https://khkgears.net/new/gear_knowledge/the-first-step-of-mechanism-design-using-gears/know-about-parameters-that-determine-gear-shapes.html (Section 3)

Thread: Connectors for multiple LED lamps
28/03/2020 18:31:12

Search Google for 'xlr multicore stage box' or 'xlr punched panel'. Maybe your best option is to buy an empty box and the correct number of sockets and assemble it yourself.

Thread: Metric thread cutting on a Colchester
25/03/2020 19:20:34

Colchester is a brand of lathe, just as Ford is a brand of car. Ford made Mark 1 Cortinas, Escorts and Capris.

You need to find out exactly what machine you have and obtain a manual for it. Read that manual very well.

From the tooth numbers of the gears you give, it is possible that you have a Colchester Student. If so, kindly read this thread:

https://www.model-engineer.co.uk/forums/postings.asp?th=150056

Thread: DIY induction motor rewind
24/03/2020 07:05:08

This is speculation, so view it critically: if you know the resistance of one of the good coils and the diameter of the wire, you can calculate the length of the winding and hence the weight. Wire manufacturers usually publish resistance per kilometre for their products. If not, you might have to go back to first principles and use resistivity of copper and cross-sectional area.

23/03/2020 18:51:21

Brocott UK. Have everything you need, including the proper varnish which is probably better.

Lots of Youtube videos on rewinding, mainly in Urdu but with enough English to understand.

Pay very good attention to the arrangement and winding direction of the coils.

Just about to try to rewind my coolant pump motor.

If the motor is not working, you will have to strip the windings so just weigh the old ones.

Thread: Lathe Advice - Colchester
23/03/2020 16:12:40

I wonder if you are limiting your options by deciding so soon on one of two particular models. With second-hand machines of this type, condition and accessories are probably more important than manufacturer and model.

If, for example, a fully-equipped CVA came along at the right price, would you turn it down? Monarch 10EE? Small DSG? Harrison M-series? And do not discount the Eastern European lathes; they were superbly built (and natively-metric).

I would be deciding on a centre height and bed length and going from there.

As for specifics of the two you mention, as Stuart said, the Student is L-taper and chucks and backplates are expensive. The D1-3 of the Chipmaster is also less popular (and hence more costly) than D1-4, which is common to Far East machines.

Out of the box, the Chipmaster has a better speed range (30-3000rpm, providing you retain the variator) than the Student, good for small stuff and modern cutting tools. Its spindle bore is a bit small and it is a bit short between centres. Requires two extra and non-standard change gears to cut 1.75mm or 3.5mm pitches. Built for people about 4' 6" tall. Check it has the 4 1/2 to 3 Morse spindle bush with it. The bed stop is good to have to take advantage of the autofeed trip (but someone has them available for circa. £50 on eBay). Chipmaster/Bantam steadies seem to command unreasonably high prices if missing.

You need to find a long-term Student owner to tell you all the niggles with that machine.

Have a look at the language of threads you want to cut and make sure any machine you buy will do what you want and has the gears with it if necessary as these can be difficult and expensive to track down.

Edited By DC31k on 23/03/2020 16:14:29

Thread: Record no 1 vice jaws seized - removal?
23/03/2020 07:29:15
Posted by Kiwi Bloke on 23/03/2020 03:17:00:

It used to be possible (may still be for all I know) to buy special vice jaw screwdrivers. These were stubby things, of hexagonal section, to take a wrench and/or cross-drilled for a tommy bar. The 'other' end was pointed, intended to sit in the slot of the opposite jaw's screw. The driver was engaged with the screw ro be removed, and located in the opposite screw by gently tightening the vice. Cam-out prevented! You might be able to use one of the screwdriver bits intended for magnetic drivers, etc., but a larger diameter is better for the gorilla-like forces usually required.

It is good to hear that the right tool exists. I have lost count of the number of Youtube restorations I have seen where they first dismantle the vice and then try to remove the jaws. Use the vice itself to assist in removing its jaws.

A cut off and ground down allen key would do the job. As well as the standard 1/4" A/F hex bits, they also come in 8mm and 10mm A/F.

A lot of vice jaw screws have a non-standard countersink angle and sometimes are quite a low head. So it is worth preserving at least one of them as a pattern for making replacements.

Thread: Measuring size for vee belts
22/03/2020 08:28:29

From the information kindly given by Nick above, you could draw the belt sections full size on a cereal box, cut them out and offer up to the pulleys to see which fits best.

Thread: What are you reading?
21/03/2020 08:41:41
Posted by Joseph Noci 1 on 20/03/2020 21:32:57:

Are there any folk here using a Kindle?

I have had one since 2013 and have not bought a book yet. There are innumerable older books on there that are totally free, which might assuage your concerns over licensing.

E.g. Mark Twain; all of Dumas' (both of them) works; Shackleton; Conan Doyle; Dickens; Austin; G.K. Chesterton; Hugo.

Something I did not yet see mentioned in this thread is the enormous amount of free material online. The Internet Archive is a good place to start.

A few notables I have found: Foundations of Mechanical Accuracy, Joshua Rose Modern Machine Shop Practice, Skunkworks (Lockheed), Truth, Lies and O-rings (Space Shuttle), Ashley book of Knots.

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