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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: Colchester Chipmaster disassemble
16/03/2021 14:15:16

It should not need drilling. Remove all paint covering and surrounding it and at about 5 o'clock looking towards the tailstock, it should be possible to tap in an old wood chisel and ease it out.

You are right that it is not shown in the manual. In the early manual diagram (BAN/9/64) the hole is shown but no plug. In the later manual diagram (CHIP-11-70) even the hole is missing. It is also missing in the Harrison 10AA manual.

16/03/2021 12:11:03

Has the gear you have found come directly off another Chipmaster? Or is it a generic 33t change gear? I hope it is the former.

When you are talking of the power feed box, are you still speaking of the apron assembly?

There is a slightly domed steel blanking plug on the headstock end of the apron, near to the half nut lever that needs to be removed. It is a little bit like a core plug in a car engine block. Behind it is the interlock rod that stops you engaging power feed and half nuts at the same time.

Once more, a close study of the exploded diagram in the manual will assist you in your work.

Thread: Water based rust inhibitor
13/03/2021 17:25:43
Posted by mgnbuk on 13/03/2021 16:14:20:

A bulk 5 litre refill container full is around £35

Compare and contrast to the Bilt Hamber product. Going rate seems to be £21.95 for 500ml and dilution rate is 2-5%.

Thread: Colchester Chipmaster disassemble
13/03/2021 16:06:17
Posted by jason evans on 13/03/2021 15:13:30:

Am I missing a gear on the bottom right spline which these link to?

Yes. Look in the cabinet or contact the seller.

Standard imperial Chipmaster has a 66t gear, a 33t gear and a 55/65t double gear (used for metric translation). The 33t is not there.

I was under the impression you had a manual. A thorough perusal of the exploded diagrams would tell you what parts are supposed to be present.

13/03/2021 14:20:31

Undo bolts holding yellow frame to cabinet. Lift motor/variator/frame to create slack in vee-belts. Alternatively, undo variator bolts and lift it slightly.

Slowly rotate thin timing belt, pulling gently towards you. It will work its way off the lower pulley.

No need to touch short, wide timing belt to remove headstock

Thread: Water based rust inhibitor
13/03/2021 14:15:03

Somewhere else, I saw this product recommended:

Bilt Hamber Atom Mac.

If you look it up and then use some of the terms it uses to describe itself in a search, you will find alternative products that work in a similar manner.

Thread: unc machine screws
08/03/2021 19:30:00

You could try modelfixings.co.uk They list them in 3/16" or 1/4" length (hex key). Also Emkay fixings and BA-bolts might be worth a look.

Thread: Colchester Chipmaster disassemble
08/03/2021 13:50:43

Remove cap screws from tailstock-end shaft support bracket. Two 2BA threaded dowel pins locate it. Remove them. Slide out leadscrew, feedshaft and bracket. Nothing impedes them at gearbox end.

Block of wood under apron to drip tray. Four capscrews to remove. Two dowels locate it. Saddle might then slide off back. If not, maybe six capscrews total front and back to remove retaining strips.

Try not to disturb the feed auto-trip mechanism adjustment (leave the worm on its shaft) during refurb.

Download the Harrison 10AA manual from the nemes site as it complements and extends the Colchester one.

08/03/2021 08:17:28

The best thing to remove to lighten a Chipmaster is the variator and motor.

The tailstock is easy but light. Unwind the cross-slide off the back of the machine. The motor door is surprisingly heavy and bulky.

After that, it is a lot of work for very little gain. Saddle and apron negligible weight. Gearbox maybe. Headstock from bed then means you have to realign on reassembly. Bed from cabinet to me is not worth it.

A Chipmaster is easily mounted on three castors using M12 or 1/2" bolts: one at tailstock end and two in motor cabinet, very close to edge (holes are already there).

Consider using a winch (US 'come along', anchored low down on the machine and pull it up the slope, chocking on the downhill side every foot.

Thread: AutoCad 2000 Query
02/03/2021 18:38:08

You can make dimension settings 'stick' by saving them as a named style.

When you do 'file', 'new', it normally allows you to choose the template drawing to be used. I believe the default is ACADISO.DWT

So any new drawing you make will inherit the text, dimension, line, etc. styles saved in its template file.

I find it easier just to take a known good drawing, 'save as' a different name, delete all the entities and start with a blank canvas.

Thread: Metric feedscrews for ML7 /S7
02/03/2021 06:53:34
Posted by Martin Dowing on 02/03/2021 00:24:50:

It looks like this screw is of mixed metric - imperial design.

Does such a screw exist at all in standard engineering charts?

Second question first: no. Another question: why do you think it should do so?

First statement: highly likely.

Put yourself in the shoes (left shoe size 9, right shoe size 228.6) of the manufacturer with a mixed metric and imperial inventory.

Consider what is easiest for your leadscrew cutting department.

Keep one size of stock in your stores. Have a bar feeder that is set up for that one size of stock. Grind tools to one angle. Flip a lever that changes the cut pitch from say 1/4" to 6mm.

Keep both metric and imperial stock in your stores. Make sure the correct one is issued when called for. Change over the bar feeder on the leadscrew machine when a different language is required. Tool grinding department now has two types of tool to make, stock, and issue.

You might do the same mental exercise on the halfnuts that mesh with the leadscrew and see the considerable advantages of minimising the differences between imperial and metric versions. Same with leadscrew support bearings.

Thread: Avoiding marking / scoring while using fixed steady.
01/03/2021 17:36:50
Posted by Bo'sun on 01/03/2021 11:19:36:

Damn, have to drink more beer.

Buy some pizza to go with the beer and use the box to make a shield that sits between steady and tool to stop the chips going places you do not want.

I saw a YT video where an O-ring was placed over the stock, I guess to stop the coolant washing the chips into the steady bearings.

Thread: What tool to measure small bores?
01/03/2021 08:33:25

The bearings will only come in a limited range of sizes and will be at full- of half millimetre dimensions. Perhaps consider some second-hand go-nogo gauges. Alternatively, some under- and over- gauge pins.

The point is that you do not need measuring capacity spanning the full 4-10mm range with a resolution of 0.02mm. You only need a very, very limited subset of this range.

With such small bearings, Loctite is your friend.

Thread: Avoiding marking / scoring while using fixed steady.
01/03/2021 07:40:19

Soft fingers, ball bearing fingers, a close fitting ring on the stock have been mentioned.

You could also try an old-style cathead and run the steady on that.

Possibly, a wrap of self-adhesive aluminium foil tape with diagonal butt joint might work.

Thread: Where to find a *good* optically flat mirror?
23/02/2021 20:10:26

There is a US site, firstsurfacemirror.com where they have an online calculator. I do not know if their products are suitable for your application so apologies in advance if this is misdirection.

Thread: boring bar
23/02/2021 19:06:36
Posted by Robert Butler on 23/02/2021 18:46:47:

Ring Jenny J B Cutting Tools she will probably know exactly what you want, a very helpful lady.

And he could be helpful to her if he does what Mr ega suggests and finds information on the bar.

A Google search for 'BBPW-508R' produces a myriad of useful results including insert codes.

e.g. https://id.c.misumi-ec.com/book/SED1_ENG_T01/pdf/0289.pdf

Thread: Help identifying a milling machine
16/02/2021 08:03:15

I think the Abene references are a little misleading. It has only superficial similarity to those - the head on the (opposite) side instead of the front. And that head is on a sliding ram with an additional Y-axis on the knee.

The photos taken from the right hand side of the machine look as if there is an additional vertical sliding surface, perpendicular to the knee ways and perpendicular to the ram ways so the whole head and ram can possibly be raised and lowered. It almost has two Z-axes and two Y-axes.

Google images will be your friend here.You have to try various combinations of 'Swiss milling machine', 'German milling machine', 'European milling machine'. These may give you some manufacturer names for further searches.

From the square shape and design of it (round, plasticated handwheels), to me it suggests late 1970's, early 1980's (compare and contrast the newer Abene models, Schaublin 22, later Deckels). The lathes site is better on the early machines than the later ones.

Another place to ask is anglo-swiss tools and the oldswissmachines io group.

If you remove a few covers, you might find date codes on some of the motors/electrics. That can narrow things down a bit.

Thread: Belt tension
15/02/2021 15:38:12
Posted by Clive Foster on 15/02/2021 14:50:38:

As Dave says the tension on toothed (timing) belts isn't great. Maybe a pound or two force to deflect its sideways at the mid point between pulleys. 5mm - 3/8 is small so tension at the low end methinks.

A good reference is here:

https://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf

Inter alia, it shows three common belts at 5mm pitch and one at 0.200". Belt and pulley profile must match.

Section 10 of the document discusses the correct tension and it should be noted that for a positioning application (perhaps where a stepper motor is used), the tension is greater than just a drive application.

Thread: Pipe bending
14/02/2021 08:02:24

Could I offer this method as an alternative?

Very simple. Just need a vice, torch, long lever, wire template...

...and 25 years of practise

https://www.youtube.com/watch?v=v8mMQbEkr8w

Thread: Vfd advice please
14/02/2021 07:52:20

Lots of replies answering his question, but could I break the trend and suggest that you may face challenges if you use a 3/4hp motor for a 3" wide sanding belt?

Further, sanding and linishing (an abrasive machining process) generally requires a high surface speed to be effective. Thus, speed control downwards from a motor's synchronous speed, even if a two pole motor is used, may not be necessary.

Simply put, you want the belt to whizz along powerfully, not crawl along, slowing down as soon as you try to sharpen a pencil on it.

So you need to start with the surface speed you need, see what diameter drive pulley you will use and select a motor rpm to give that surface speed. Then look at what motor is required to produce the necessary torque at that rpm.

To me, the 3/4hp seems way underpowered.

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