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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: Choosing a boring head
27/08/2021 10:09:07

The point about the grinding was his specific requirement of a 25mm starting bore, an 18mm dia. bar and a 6mm dia. toolbit.

If the bar is 18mm dia. and centred as shown in the plan, the annular space is 3.5mm. The grind on the cutter shown looks to be roughly half of that, 2mm in plan. I do not know how easy that is, hence the question. Drawing it out as you have done is the way to see, and as you say, presenting the bar at 45 degrees gives more space. Maybe some dimensions on the toolbit would allow assessment of practicality.

Also, if necessary, the bar does not need to be concentric with the hole. It could move to the right to give more space.

Thread: Chipmaster motor wiring
26/08/2021 07:32:00

Looks good.

If you want extra peace of mind, you could remove the jumper wires and measure the resistance of one coil (or all three individually and average). Add back the jumper wires but not the phase wires and measure the three phase-to-phase resistances. They should all be the same and you can calculate the value relative to one coil.

Thread: Choosing a boring head
26/08/2021 07:01:24

As you are buying for one specific job initially, it is worth assessing the tools against the requirements of that job.

All the Oilite literature recommends razor sharp tooling for single point cutting of its material.

You have to ask yourself if you will be able to fulfill this requirement by hand-grinding and lapping the supplied carbide bars, which are of unknown composition.

It is much easier to produce a razor sharp HSS tool than a carbide one.

As the heads take 12mm shank tooling, a standard 12mm dia. carbide-tipped lathe boring bar would fit (with some length reduction) and this gives you option of off-the-shelf razor-sharp tips designed for aluminium. You would need to check the minimum hole size a 12mm bar will enter.

The bush hole is 25mm dia. and the supplied HSS bit holders with the 62mm dia. head are 18mm dia. This means there can only be 7mm projection of the round toolbit (and you have to start with the head adjusted 'behind centre'. Are you able to grind the necessary cutting geometry onto a 6mm dia. toolbit within this space? A little more length might be available if some of the grind is inside the bar, but this will reduce the effectiveness of the bit clamping screw.

My conclusion is that either head you show will do the job, but make or buy or adapt a boring bar that will work for the job you are doing. Send all the supplied tooling to a drawer for future use.

Thread: Chipmaster motor wiring
25/08/2021 18:55:02

The wires are labelled. The motor is connected in star. Red, blue and yellow are the three incoming phases from the control box. They connect to one end of each of the three motor coils. The other end of the motor coils are under the curved link bars.

You can easily rearrange it to delta. You will end up with three wires on three terminals: one incoming phase wire, the 'beginning' of a coil and the 'end' of the next coil. The three unused terminals can be used to store the now unnecessary link bars.

25/08/2021 10:34:50
Posted by larry phelan 1 on 25/08/2021 08:39:15:

I don't think it's the starter you should be looking at.

I think if you read his post with rather less of a pedantic eye, you will see that his use of 'starter' is a slip of the keyboard.

Where he says, "(it's very awkward to see due to the position of the motor below the variator) and it's round with a couple of very nice curved links", he is indeed talking of the connection box on the motor itself.

The motor on the Chipmaster is of an old style that uses a round terminal block rather than the more modern rectangular one that is shown in the pictures he has seen.

The form factor is not relevant. It is just a six wire terminal block, currently wired in star. All coil ends are brought out to the terminal block so delta is not a problem.

See also:

http://wanderingaxeman.blogspot.com/2013/03/colchester-chipmaster-oils-instruction.html

Thread: Dickson tool post
25/08/2021 10:24:40

You need to solve the problem in a systematic way. Number your holders and letter your slots. Try every combination and document pass or fail. Then you may see a pattern emerge.

This will allow you to identify if it is a holder problem or a post problem or a combination of both.

Undoubtedly, the mating surface against which the locking knob that is activated by the cam pulls will be a different measurement on some holders. Shimming that as suggested above will solve a lot of issues.

On the post itself, some logical swapping of the cams and locking knobs may assist (three cams, three knobs, and three positions).

Thread: GEAR HOBS: Where's my missing video!!
25/08/2021 06:41:48

Like most electronic storage mechanisms, YT is at best a temporary repository for information. Foe anything that is really important to you, it is worth making your own back up. Please look up youtube-dl , a well-specified open source program that might eliminate the unnecessary overuse of your exclamation mark key.

Thread: small toothed belts
19/08/2021 06:20:36

It is not clear from your post whether you want belts that run on smooth pulleys (known as asynchronous) or belts that run on toothed pulleys (known as synchronous).

A good place to start to survey the market is manufacturer's websites: Gates (not Gareth or Bill), Fenner (not Dave or Keith), Mitsuboshi (sic, not the car maker).

Thread: Ruggedising a Type 17 Stepper motor electrical connection
18/08/2021 17:25:29

Plenty for 23 and 34, so they may be a starting point for inspiration, search terms or suppliers:

https://www.soigeneris.com/stepper-motors

https://www.thingiverse.com/thing:2481149

https://www.cnccookbook.com/gorgeous-nema23-stepper-motor-back-covers/

https://cnc4pc.com/3d-printed-back-motor-cover-kit-for-nema-23-60mm-570oz-in.html

Thread: Interfering with fits?
16/08/2021 06:28:15

If you go with an engineering adhesive (Loctite-type product), rather than listening to numbers people pluck out of the air or that emerge from other parts of their body, download and read the manufacturer's data sheet for the particular adhesive you propose to use.

Thread: Which is better Thompson or er collets
13/08/2021 17:46:32

Please could you clarify as I have never heard of Thompson collets. The most common Autolock collet system was made by Clarkson.

If it is Clarkson collets you are speaking of, the topic has been discussed in the past on this forum, so a search would bring forth the most common views.

Thread: Broken keyless chuck
12/08/2021 19:08:13

Try these as an aperitif:

https://www.machinistblog.com/rebuilding-an-albrecht-drill-chuck/

https://www.penntoolco.com/content/AlbrechtPrecisionReplacementParts.jpg

Thread: Unusual Go-No Go Tool?
10/08/2021 06:13:53

The scale on it is non-linear (perhaps logarithmic), so that eliminates a vast amount of possible applications and opens up other possibilities.

Thread: Change Gears Identification
09/08/2021 06:26:40
Posted by Martin Connelly on 08/08/2021 23:50:17:

...perhaps they are for BA pitches.

If they are for BA pitches, then the tooth numbers would be 'stange' numbers, probably all odd numbers.

The ones shown form a nice sequence of even numbers 'by fours'. That might be a toehold into their identification: you can eliminate all machines that were supplied with gears 'by fives'.

Thread: Colchester Bantam Lathe
08/08/2021 20:22:16
Posted by Gaz Lippid on 08/08/2021 19:52:08:

...the manual is one thing I don't have...

Fourth post here:

https://www.model-engineer.co.uk/forums/postings.asp?th=133708

Thread: Machining Radius
08/08/2021 18:56:41

His drawing shows decimal degrees, so the angle is a little under 41 1/2 degrees. You can check it by doing inverse cosine of 18.75/25 .

The reason for writing is to suggest you think a little about your machining strategy. If you are driving along the straight bit towards your stopping point, as soon as you hit that point, the amount of cutter circumference engaged in the work increases drastically. At the very least, the finish on the part will be inconsistent.

It may be better to plunge cut the four tangent holes (perhaps with a 3/8" cutter) so the bulk of the material is removed before you drive into the corner.

Thread: Mystery Insert
05/08/2021 18:53:13

What is the purpose of the tool? It looks to me like a boring bar that goes in a Wohlhaupter-type head.

Do you know the manufacturer? It is possible that it is a non-ISO insert, so determining the maker of the tool would seem like your first step on the road to success.

Thread: Collet chuck identification please guys.
03/08/2021 17:32:26

Rotagrip have some info. on the various-sized Burnerd collets in this document:

http://www.rotagriponline.com/datasheets/Pratt/PrattChuckSpares.pdf

Briefly, there was EB, EC and ED. EC is by far the most common and the other sizes are unlikely on D1-3.

Please also read the information here:

https://www.mig-welding.co.uk/forum/threads/today-i-acquired.50192/page-1490

concerning the closing ring of early models needing modification to accept 'E'-series collets.

Thread: Metric thread dimension wanted.
01/08/2021 10:30:47
Posted by Pete Rimmer on 01/08/2021 08:52:09:

That's a handy look-up table but it's rather ridiculous giving the dimensions in a millionth of a millimeter.

There are many potential users of a Standard, from someone messing about in their garage, though gauge makers to someone like a UKAS calibration laboratory.

If the Standard is to cater for all of them, it needs to be written in that way. You can ignore figures that are beyond your required precision, but you cannot just assume figures if the stated precision is not enough.

What is the alternative? A Standard for ISO threads for garage tinkerers, another one for those with more exacting requirements and a third one for UKAS?

Thread: THREAD IDENTIFICATION
30/07/2021 17:34:05

If we are going for a 'nearest the bull' on thread angle, diameter and pitch (one dart for each property), can I use my three arrows to hit M11 x 1.0? It is closer on two out of three counts than anything thus far suggested.

Edited By DC31k on 30/07/2021 17:37:21

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