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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: Useful MEW Table
08/12/2020 10:55:22
Posted by Journeyman on 08/12/2020 10:37:12:

This information is from a now defunct website "Watchman"...

For the sake of clarity, it might be useful to stress that you obtained this table from that website but in no way is that place responsible for its original compilation.

If you put 'bodgesoc thread table' into Google, you will find its true genesis, Andy Pugh, who is also a member here.

Credit where credit is due and all that...

Thread: Threads on milling cutters
04/12/2020 16:03:54

It is worth reading the datasheet for the proposed 'glue' before you begin.

To work best, it needs some clearance and surface roughness to give a film thickness and a good bond. Hence a reamed hole might not be the best and a rub of the cutter shank with a coarse diamond stone will not harm anything.

04/12/2020 13:35:57

Drill extension bar 6mm. Loctite. Let it cure. Use it.

Thread: COLCHESTER BANTAM PROBLEM
03/12/2020 13:28:08

If you put t2b-3-20 into Google, you obtain many results. Try this one as a starting place:

https://www.klocknermoeller.com/moeller.electric/2008/rotary-switches.pdf

It looks like the part numbers have changed, but I think the one you have is almost the exact centre of page 10.

As you say, it is an absolutely standard rotary drum switch. Every proper manufacturer will make one with the equivalent functionality.

If you cannot find one with an identical arc of operation, that is an engineering challenge that might easily be overcome with some thought.

Thread: Tool for rounding and edge of metal plate
27/11/2020 14:23:48
Posted by JasonB on 27/11/2020 13:03:56:

roundover 3.jpg

 

The challenge with the 45 degree method (RHS of sketch) is positioning the cutter correctly so the mid-depth of the plate passes through the radius centre. Easy to do on a picture, some thinking needed for real metal objects.

The LHS will only work if the cutter radius is half the plate thickness. Otherwise the curve produced will always be imbalanced on the plate.

Edited By DC31k on 27/11/2020 14:26:43

Thread: Bearing identification
26/11/2020 17:56:51
Posted by Hopper on 26/11/2020 10:46:56:

It's in the suffixes.

XXXX2H indicates the inner and outer races are made from a special high temperature tool steel.

XXXXX2RS indicates its a both-sides rubber sealed bearing, of the standard type.

So your original would be a heavy duty bearing for higher temp operation, such as heavy load without recirculating oil lubrication etc. to keep temperature down.

The suffix is only true if the XXXX in both cases is in the same language. In the case of the bearing under discussion, 99502 is not an ISO designation (I have failed to determine to which, if any, naming standard it does belong), whereas 1632 is ISO and the chart to which you link is specifically for NTN bearings*.

Other references, and indeed the original poster, refer to it as an agricultural bearing. Many of the listed applications are ride-on mowers, hardly an application for high temperature tool steel. (https://bearingsdirect.com/agricultural-ball-bearings/99502h-agricultural-ball-bearing-5-8x1-3-8x7-16-sealed-sc0228lu)

It is interesting that some of the descriptions of the 99502 bearing market themselves as being made from a special chrome tool steel, which, when you check the standard mentioned (SAE-52100) is a standard bearing steel. The snake oil is marketing this bearing to mower people is probably the same as that marketing gold plated plugs to hifi people.

* I particularly want to buy a C2 bearing off them, to check it the table is correct.

Thread: Rotary Table Quest
21/11/2020 21:08:17

It is rather sidestepping the question to try to segue seemlessly from discussion of a RT with dividing plates to its use in angular indexing by means of a graduated handwheel.

If we do not throw away the dividing plates quite so casually, how does the worm ratio affect the precision?

I believe the Hardinge brothers, who made the 4:1 ratio device, knew a little of what they were doing.

Thread: Ball ended handle - how to
21/11/2020 20:28:51

Both GHT and DH Chaddock cover this in great detail in their books.

Use a split collet to hold it.

Thread: Rotary Table Quest
21/11/2020 20:23:33
Posted by Howard Lewis on 21/11/2020 20:06:28:

The HV6 is a 90:1 ratio which allows more precise positioning than tables with 72 or 36:1 ratios.

Please could you expand on that remark.

What is the correlation between worm ratio and precision?

Doe it mean a 40:1 ratio is more or less precise than a 90:1? And what of a 4:1 ratio used by one of the big US milling machine makers?

Thanks.

Thread: Camlock D1-4 chuck won't come off
21/11/2020 19:01:16

Glad it has worked out. Hopefully I am not teaching you to suck eggs, but are you aware that the spindle should have a mark on it somewhere between two of the cams and that everything that attaches to the spindle should also have a mark on it which should align with the spindle mark?

This is to ensure that every time you mount a particular item, the same pin goes in the same hole, so that if you have tuned the pin lengths to get correct locking, it will always repeat.

Type 'camlock stud fiddling' into Google and save the document by Robert Bastow.

Edited By DC31k on 21/11/2020 19:01:31

Thread: Insert for internal ACME thread?
19/11/2020 20:24:15

As others have said, 8 tpi ACME form is not available in 11-series laydown inserts.

See: https://www.rileyshutt.co.uk/ProductGrp/0016000300260001 for example where the coarsest 11-series pitch is 10 tpi.

If you want a pre-ground tool, have a look at these and then try to find a UK-stockist

http://internaltool.com/products/lathe/19/acme-threading-tools

https://www.carbideanddiamondtooling.com/Carbide.ID.Acme.Threading.Tool.29.Degree.4.5.6.8.10.14.16.TPI

https://www.micro100.com/products/standard---threading-tools---acme-threads

On edit:

go here: https://www.premierformtools.co.uk/ and look for SimTurnDX as that meets your requirements. Whether it meets your budget is another matter.

Edited By DC31k on 19/11/2020 20:32:29

Thread: Making end / slot drills
18/11/2020 15:32:44

There's 1, maybe 1 1/2 pages on this in Workshop Practice series No. 5 Milling operations in the lathe by Tubal Cain (beginning of chapter 9).

An alternative, Woodruffe-like cutter is in Arnold Throp's earlier book in the same series.

Thread: Machining Ball Screws Accurately
18/11/2020 08:21:48
Posted by Ian P on 17/11/2020 20:53:22:

Its the last sentence that is the problem, See Joe's post about clocking

Thanks for that. I knew there had to be a flaw in something so simple.

Can I run another option past you? Select a 3-jaw self centring, set-tru chuck with the ball(s) in the jaws. Calculate the minimum gripping diameter of the balls when they are clamped on the pitch diameter of the ballscrew. Grip and dial in a circular rod of that minimum diameter. Remove rod and replace with ball screw.

A possibility if there is no set-tru available is to put a grub-screw behind each ball and use that for dialling in (slow the balls down with a bit of silicone sealant).

17/11/2020 20:48:39
Posted by Kiwi Bloke on 17/11/2020 20:15:50:

So, balls in the thread, sleeve outside and sleeve held in 4-jaw? But getting the sleeve ID correct means measuring over (3) balls in the thread, which is awkward.

Is there any opportunity to develop this method and use soft jaws, each jaw counterbored for one or more balls of the correct diameter to suit the screw, with the counterbores spaced at 1/3, 1/4 or 1/6 of the thread pitch apart to suit number of jaws and 1 pitch apart if multiple balls per jaw?

Especially with a 4 jaw independent chuck, you would be gripping on the thread's pitch diameter and could then dial in concentricity in the normal manner.

Thread: Taper sleeve adapter
14/11/2020 19:03:42

For completeness, this thread has some useful information:

https://www.model-engineer.co.uk/forums/postings.asp?th=142458

14/11/2020 07:51:06
Posted by Me. on 13/11/2020 22:40:18:

The 40 is too big and the 30 too small

Are you aware that there is a 35 taper in between 30 and 40? See:

http://www.tools-n-gizmos.com/specs/Tapers.html

Thread: Tri-Leva decal artwork?
13/11/2020 20:14:47

This thread on Myford fonts might make interesting reading for you, particularly the comments by Nick Clarke 3:

https://www.model-engineer.co.uk/forums/postings.asp?th=157921

To make a facsimile copy is very time consuming. I would estimate 8+ hours for the above.

I have had most success importing the photo (the deskewed one above is more than adequate) into a CAD (Turbo-, Auto-, Intelli-, etc.) program and drawing each letter individually.

On this plate, it is quite good as each digit only needs drawing once, there is a lot of duplication of 'speed', 'motor' and 'pulley', and 'speed' 'selector' at the top share a lot of common letters.

13/11/2020 16:45:55
Posted by Adam Mara on 13/11/2020 15:46:46:

Did a quick mock-up in Coreldraw.

That is good. I get the feeling that the OP wants a facsimile copy of the original rather than something that has the same information on it.

Is it possible in CD to over- or under-lay the photo above onto your own and adjust fonts, letter proportions and spacing to more closely match the original (e.g. look at the right hand lever - its 'stalk' is between the 'U' and 'L' of pulley)?

Thread: T51 Dixon style tool holders?
13/11/2020 09:40:06

Start here:

https://www.model-engineer.co.uk/forums/postings.asp?th=135594

Continue here:

Google "dickson toolpost dimensions" and look at images.

Try a different combination of eccentric cams, sides and top-hat parts (number the holes 1 & 2, the cams 1 & 2 and the top-hats 1& 2. Try all possibilities).

Thread: M G Electrics (Colchester) suds pump wiring.
11/11/2020 08:07:07

It is a good motor: it will run happily on high voltage 3-phase, low voltage 3-phase or single phase (with capacitor).

Are you quite sure on the five wires? It should be six, one for each end of the three motor coils. When I took mine apart with a view to rewinding it, I do not remember the star point being buried. This was an old one with the switch on the top of it.

Most modern motors you see have six-way terminal blocks as standard, with brass bus-bars, to allow star or delta connection.

I think the only thing different in this motor is the terminal block itself; it only has four connections, for star operation. If you change it for a six terminal block, you will have all options open to you.

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