Here is a list of all the postings Bernard Wright has made in our forums. Click on a thread name to jump to the thread.
|Thread: Dismantling a Pratt Burnerd Grip Tru Chuck|
Hi Andrew, just a suggestion, measure the broken end of the tapered screw.
Find a good bolt of that diameter with enough shank to reach the remainder of the screw in the chuck body.
Cut off the excess shank, place in your lathe chuck/collet and drill the largest through hole without weakening too much the bolt shank.
Providing the hole is big enough to accept a 0.6/1.0 MIG wire or even a 1.6/2.5 welding rod with a bit of insulation on it (the reason for the insulation is to provide positioning ease without premature arcing, probably some very small plastic tubing (windsreen washer pipe)).
If the previous procedure is attainable, insert the insulated welding medium into the hollow bolt and with a gloved hand position onto the broken screw and weld the hollow bolt to it.
I would think the heat shock would hopefully loosen the seized screw.
Hope that may be of help.
Edited By Bernard Wright on 12/04/2020 17:29:54
Edited By Bernard Wright on 12/04/2020 17:32:12
|Thread: What are these for|
They look like drive trips off a machine with a movable table ie. milling machine or engraver...
|Thread: 1 inch reamer|
Hi, have you tried Tracey Tools in Torquay, they often have non-standard items, usual disclaimer.
|Thread: Straight Bevel Gear Question|
Pleased to hear you managed to accomplish a sound repair, did you use a tap, or did you thread cut with a ground up tip.
I bought a 6Tpi Acme insert, only to find it needed a bar bigger than the root diameter of the blank, at 6Tpi they go on to 22mm tips as opposed to others at 16mm, bugga.
I do intend to sort it, but other things are in the way at the moment.
I would appreciate pics, might just give me the spur on.
Sadly I've done nowt with the Buma, I moved to Scunny May 2017, and I'm struggling to find everything.
Doing other jobs for myself that needed fixtures or mandrels, became a real chore, especially upon finding stuff I'd already done, after making bits anew.
Also I'm a bit limited doing recreational machining, as my Wife is really suffering with Osteoarthritis in her left hip, being her hubby I'm also her Carer, so the learning curve seems like a Mandlebrot.
I started making a universal dividing head for my Clarkson, but it is taking damned weeks, again everything seems to be a 10:1 job, but I've plenty of time.....
|Thread: Oversize ER collets|
If you still need to go the ER Collet route, Barry @ Gloster Tools (mainly on @Bay) does all the individual oversize collets, at the most reasonable prices I've come across, including free P&P.
I have NO association with Gloster other than a very satisfied customer of quite a few years.
|Thread: Autocad 2000 Cant draw at a chosen angle.|
Press F8 and that turns ORTHO (Horizontal and Vertical) off.
You can then draw your lines at any angle to the degrees indicated at the curser location, press F8 again to turn it back on.
F7 for GRID on and off, F9 for SNAP on and off.
F3 for OSNAP on and off.
I use them constantly, I used to put masking tape along the top of my keyboard, and print the AutoCAD functions above the 'F' keys, don't need to do it now....
|Thread: AutoCAD substitute|
Just had a look for Draftsight on the Dassault Systemes site, they're only offering the new 2019 version which has to be paid for, and the 2018 version stops working at the end of this year.
Edited...This is already covered, sorry for jumping in.
Edited By Bernard Wright on 29/04/2019 01:35:39
|Thread: Straight Bevel Gear Question|
The tap I used is a proper 3/4" x 6 TPI Acme tap, but I fear Buma made their leadscrew and nut a propriety 3/4" x 6 TPI Acme, the threads on the leadscrew do seem excessively deep, and the tap will not enter their nut, indicating a smaller core diameter.
I will post some pictures in my album.
Thank you all for your replies, the mating gear is 12 teeth at 90 degrees, so it would be 2:1 reduction at that point, the smaller bevel is driven through a worm.
JasonB, that is the route the replacement nut follows, but a bare nut is £80+ so I'd rather play with it myself.
Andrew, this is the knowledge I seek, before tripping myself up as usual, the offer of CNC'ing a nut is attractive, I have a lump of 2" dia Aluminium Bronze, which could be tried upon, I live in North Lincolnshire, if that's reasonably driveable.
John, strangely enough I have his book (Ivan Law), but it is stored away awaiting my moving.
As a trial I tapped a lump of hollow Bronze with a 3/4" x 6 TPI Acme tap I bought at Normous Newark Autojumble for £5, but it tapped too large for the existing leadscrew, I ended up with as much play as before.
I suppose I could tap out the nut with this tap and make new leadscrew, but I would like to try the bevel gear cutting.
I hope someone can help me, I'm totally out of my depth with this.
I have a 'Buma' Boring Bar I'm trying to make accurate, the feed is controlled by an ACME thread of 0.75" x 6 TPI, the driven nut is bronze with a straight bevel gear machined into the top.
The threads have so much slop that a controlled cut is impossible.
I would like to try and make a new nut, but I'm struggling to calculate the bevel gear.
It has 24 teeth and I've measured the top down angle as 23.5 degrees, and the body is 1.612" in diameter.
I presume its of DP type not Module, due to it being British and quite old.
Ordering a suitable cutter shouldn't be too difficult, it's just working out by how much to tilt the diving head to get the taper tooth accurate, and calculating the root angle from the measured top angle, that the cutter needs to approach the cut.
I've a universal diving head and rotab to mount it on, to get the compound angles, if someone could point me in the right direction hopefully.
Thanks in advance for any help offered.
|Thread: Tightening jacobs chucks|
Everyone has their own preference, whether acquired or impressed upon through training.
I sometimes use more than one pinion hole to try to centralize whatever I'm try to hold, as a rule I only use one hole as in tailstock usage.
Also I use four differing sized drill chucks for appropriate size drills or reamers, as I don't like too much of the jaws extending out of the body, I feel this would produce bellmouthing eventually.
As for the three jaw selfcentring lathe chuck, some people tighten all three, in the past to try to centralize a workpiece, I've used more than one pinion, usually only slightly beneficial, after converting said chuck to 'GripTru', I use only one pinion adjacent to the badge.
I bought a new Pratt Burnerd three jaw chuck, which had on of the pinions marked with a zero, so I use that preferentially.
Edited By Bernard Wright on 23/01/2017 15:37:10
|Thread: How do I make a simple, flat torsion spring? (in stainless?)|
Search 'eBay' for 'Spring/Music/Piano Wire', I've bought different sizes off of there, quite reasonable prices including P&P
|Thread: RDG involute gear cutters.|
This is an Involute Gear Cutter from RDG, I'm using it on a shopmade arbour and didn't notice any eccentricity, maybe that was the reason..
The material being machined was En24T with coolant, worked extremely well, the wormbox gear is for my Son's Bantam.
PS there's a few more photos of this in my album....
Edited By Bernard Wright on 04/11/2016 18:13:44
|Thread: Another Colchester Student|
Hi, I have a Master which I believe is the bigger brother to the Student, but very similar in construction and usage.
By not engaging top speed, I presume you mean the front central lever not going from right to left (counterclockwise)
Or are you referring to the top levers, I sometimes have trouble with lefthand one not wanting to engage unless the chuck is rocked, these levers can be a source of trouble, this can give a horrible rumbling/grating noise.
As has already been mentioned the main headstock bearings are extremely expensive, prohibitively so for an aging machine.
|Thread: Running several 3 phase machines|
I use one VFD for three machines, as I'm not very good at multitasking, and can only use one machine at a time, so there are no problems at all.
Even setup a distribution board for the lathe and miller, to incorporate a changeover switch using the same breakout box, as they are close together.
The drill has its own breakout box and is routed via an extension lead, also fitted a 7 pin socket to the VFD, for the breakout box changeover.
Not sure about what the interference is though...
|Thread: Modifying a Master Roundhead|
Made some progress on my Cross-slide mod.
Machined a new thrust bearing block, to fit in its carrier on the taper turning slide.
This new block houses a single Double Angular Contact bearing, as opposed to 2 open ballraces that require preload.
However, I've now eliminated that perceived play, but that mow highlights the wear in the cross-slide screw threads.
There is an anti-backlash adjustment, but when adjusted to near zero in one spot others are too tight.
So I'll have to make another leadscrew and nut in the near future, here's a couple of links to a photo slideshow of the various stages of progress...
|Thread: Hello from Edinburgh, Scotland|
Welcome Archie, you'll find a great bunch of helpers on here, some of us are still learning, sometimes the hard way.
|Thread: Modifying a Master Roundhead|
Before embarking on this latest route of trying to get things how I want them now I've retired, I set about moving the Headstock over slightly to guarantee unsupported parallel turning, seems to have worked.
Then I moved the Drive Motor out of the base of the lathe to a position on the rear of the bed below the headstock.
The reason for this was to try and eliminate a vibration problem I posted about earlier, the drive belts were 78" long making the pulley centres about 3' apart, the belt wip generated by the VFD driven motor was of concern to me.
I'd almost eliminated most of the vibes but still wasn't happy, anyway I've cobbled together another YouTube photo collage.....
Added a small collage of pics of the proposed conversion and Cross-Slide prep..
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