Fixing Darren's lathe

[sbwhart]

Hi

Harry sounds a real good guy, some of those small jobbing shop do some fantastic work and the men working in them have loads of experience, they have to take on what the market throws at them or they go out of business, working in a big factory with a limited product range you don't get the same exposure. Unfortunately society nowadays just doesn't value them sort of skills.

I'm sounding like a grumpy old man:--- well thinking about it yes I am.
 


Cheers

a Grumpy old b****r

Stew

[Bernd]

As I said earlier if I find my set of taps I'd post a pic. Here they are. Taper on the left, plug in the middle and bottom at the right. These taps are 1/2"-20 NF.



Bernd

[bogstandard]

Bernd,

We use the same taps, but name them slightly different, taper, second cut, plug.

Now on with my post.

I was hoping this would be the last one, but I could only manage about an hour today, so I will show you the results.

This part of the job is a 'wing it' exercise, in other words, make to fit.

Because the new blocks are a lot thicker than the original crappy gib strips, a problem occurs where the gear that runs on the rack for moving the saddle, actually fouls the newly made blocks.

This is from the side.




Front shot.




By taking the gear off it's spindle, I managed to get the apron bolts in and the spindle almost resting flat on the top of the block.




This will do for me to mark out where the cuts need to be.

I run a pencil down the outside of each side of the spindle. I then found the rough middle between the pencil marks, measured the diameter of the small gear, halved it, added 1/16" and marked out from the centre line on both sides.
I thought I had taken pics, but couldn't find them, so the above description will have to do.

Senility is definitely setting in.




I checked that the gear clearance was ok either side.




Stuck my scriber through the middle of the gear, and held the scriber on the top of the block, and pushed the gear down as far as it would go, and marked it up plus a little bit. It measured up at 0.200" down.




I am showing off here, because I had a bull nosed cutter of the right size, but I could just as easily cut out the square recess.




Block mounted back onto the saddle.




Apron fitted into correct location.
If I must say so myself, it worked out a lot better than I thought it would.
It is about time I had a bit of luck.



So the rack was mounted onto the lathe, followed by the above assembly. I put the gibs in position and tried it out.

Looks like we are onto a winning streak.


Bogs

[Divided he ad]

Nice fit! 



Next stop.... Turning?




Ralph.

[Brass_Machine]

Nice fit John!

Eric

[SPiN Racing]

Beautiful!

 

[NickG]

Looks great John, can't wait to see what it's like!

Nick

[bogstandard]

Thanks lads, it seems to be working out well.

Next is, cut gibs to length and cut an adjusting slot in them, plus make the adjustings screws.

It is the last bit that will cause most people the problem.

You will need a lathe to turn the adjusting screws, and you can't use your lathe because you haven't got adjusting screws.

The perfect catch 22 situation.

At times like this, you need a friend with a lathe (or make the screws before starting the mod, and hope they fit at the end).


John

[NickG]

Haha! 

Do you have any plans for the cross / top slides John or are they acceptable? I'd never come across this type of gib until I got my harrison but have to say, they are so superior to a row of grub screws!

Nick

[bogstandard]

Nick,

To modify the top and crosslides is a totally different kettle of fish.

The tapered gibs I am doing just run between two flat surfaces and is all kept in line by the prismatic top to the bed and the groove I put into the bottom of the gib strip, so a very easy mod.

The other two slides work in a different way, to withstand both heavy lifting and sideways forces, they work on a dovetail system. To do this mod on those, requires a dovetail with a slightly tapered lift face on one side, and the casting would most probably need to be machined with a dovetailed tapered slope and a matching tapered angled sided gibs. Most modern machines in larger sizes are now fitted with tapered adjustable gibs, and they are far superior to the normal flat gib types.

If I was doing this mod again, I would most probably do it slightly different, giving much better stability of the gib strip and easier adjustment, based around the normal tapered gib strip method. See C-o-C

John

[Bernd]

Nice one John. That last fix would have taken me more than an hour to complete.

This whole thread has got me thinking I should take my Grizzly apart and check the ways like you show. May just happen sometime.

Thanks for a very informative thread.

Bernd

[bogstandard]

Bernd,

I am no superfast machinist, in fact I spend more time looking at the job rather than doing it. But once the decision is made, it gets done.

I think the machining only took about ten minutes at normal machining speeds, so for a normal person, maybe 20 mins all in, and that includes all the measuring and marking out.

I only give timings so people know what to expect, not for boasting. It isn't a race, just take your time, plan and think well ahead, and it should all go smoothly with no unforseen hitches.
I have said before, I look at a job, and have machined it in my head many times before cutter touches metal, I think that is why my recycle bin doesn't fill up very fast.

John

[Bernd]

Here's what I'm saying John, it would have taken me a bit longer for the whole exercise, "Thinking" that is. Haven't had to do it enough to cut the time down.  I can machine it in my head to, but I seem to have a bit of a problem when it comes to actually doing the machining. I seem to run into problems then. So by the time I fgure it out a lot more time has gone by. But I'm gaining on it.

A good example is the indexing devise I'm modifying. It's taken me several days to come up with a method of holding the index pin and making a clamping device. I'll explain when I get started on the next part of that project.

Bernd

[sbwhart]

Hi Bernd

We all nead thinking time, that's what so great about this game, it keeps you thinking, I'm usualy thinking ahead on two or three projects, my boss is always bol***g me for not listening to here little does she know I'm thinking about how to make something. The big worry is when she say's  OK thats agreed too, ho Sh one t what have I just agreed to ????.

 

Keep thinking

Stew

[Bernd]

Stew,

I keep telling mine I'm making jigs and fixtures to build her kitchen cabinets. So far it's worked. She does question why they are made out of steel and are so small. Don't look anyhting like her cabinets. 

I keep thinking what to tell her that I accomplished today. Made jigs and fixtures I say.

Bernd

[bogstandard]

You got it all wrong lads. Let them make up your mind for you.

I give mine the choice, either I watch the television and have what I want on, or I go out to the shop.

She can't make me a cup of coffee fast enough, and get me out of the door.

Isn't it nice to be loved?


Bogs

[Darren]

That's B****y funny John....

Mine would prefer me in the cellar/workshop too.....so she can have the telly would you believe.

As long as you insist on flicking it over when a, Soap, talent show, house program, dancing, singing (insert your own choice here) comes on and watch top gear or CSI or whatever she hates then the workshop is all yours.....

In reality, you could throw the TV out fo all I care....

[SPiN Racing]

HA HA HA HA

Ya know.. when it was time to build my garage behind the house I held up two sets of plans.
A single car garage...
A 3 Car garage with a STEEP roof. And extra room.

I told her I can build the single car to park the car in, and rent a shop someplace 30 minutes away to WORK on the cars.
It will be cheaper.

OR I can build Gigantor Garage, cost a lot more money.. but I will be out back.

She was perfectly happy to help direct me when I was driving the bulldozer around moving the 20 truckloads of dirt to raise the foundation for the bigger garage.

Now.. Honey Im going to the garage!... 6 or 8 hours later I ask nicely for some sandwiches.. and Im happy. SHe has the house to herself, and can play music and work on her PC doing her graphics stuff.

[bogstandard]

What day is it today?

You guessed it, The dreaded FRIDAY the 13th

First John S bu**ers up his baseplate, now I have a problem. What's the betting, when Darren comes to fit the pipe into the flange, he has cut the wrong size thread.

Anyway, Stew called this afternoon, and after a bit of fat chewing, we went out to the shop to show him how close Darrens' lathe was to being finished. I mentioned that maybe I had seen a problem that I hadn't seen before.


So after Stew had departed, I dragged myself back out into the shop to check things out.

I had already made the adjusting screw blanks, ready for thread cutting and having a screwdriver slot cut into the end.
I had calculated out that I would require an 11mm diameter flange to sit into the slot for pushing/pulling the gib strip up and down the slope. That worked out fine for the operators side, but when I checked the rear, the flange would catch on the casting. So without further ado, I threaded one of the screws, wacked a slot across it, and sure enough, the casting was stopping it being central with the hole. So I gradually reduced the flange size until it just fitted into the hole without touching the casting. See how close the flange is to the casting. It ended up at 8mm diameter.




This is the major problem it causes.
As the gib is screwed further into the holder, it rises. As you can see, this isn't all the way in and the flange is almost out of the slot. 11mm is perfect, 8mm is definitely no use.




THE SOLUTION


If I blank up the old 4mm hole, and drill and tap a new one roughly in the position shown. Do a little bit of silver soldering on the gib strip to make it look tidy, recut an angled slot acoss the corner and this should work a treat.




So much for working to plans.



But anyway, today wasn't such a dead loss after all. After I got back from the torture camp (physio), I found a rather large pile of solid tungsten mill cutters waiting for me. Isn't it nice to have friends.

Time for a little share out between visitors.

Bogs

[sbwhart]

Hi John

I could tell when you showed me the gib strips there was something niggling you  blanking the hole off and re-taping should knock  some good manners into it.

today wasn't such a dead loss after all. After I got back from the torture camp (physio), I found a rather large pile of solid tungsten mill cutters waiting for me. Isn't it nice to have friends.

Time for a little share out between visitors.

John kindly shared some cutters with me and very good cutters they are too  Thanks John 

[bogstandard]

I am not saying that the plans are wrong, but one set that works with one machine, might not work with another.

I have carried out other work to this lathe, and that might have a bearing on the outcome, but I very much doubt it.

I also repositioned the screw adjusting hole slightly lower (only a very small amount) than shown on the plans, purely to allow a beefier screw to be fitted. That would have some bearing on my problem, but not to the extent I am getting.

So if you are considering this mod, get all your facts and figures first, or leave drilling the hole until the last moment, so you won't encounter the problem I have hit.

I thought I had all points covered, and at the last minute, this jumped up and bit my a**e.

I will now see if my solution works.


Bogs

[John Stevenson]

But anyway, today wasn't such a dead loss after all. After I got back from the torture camp (physio), I found a rather large pile of solid tungsten mill cutters waiting for me. Isn't it nice to have friends.

Time for a little share out between visitors.

Bogs

I'm on me way 
Black coffee one good spoon of coffee, one good spoon of sugar.   

JS.

[bogstandard]

John,

We are not talking about an artic full here, just a nice pile. By the time they have been shared out, maybe one or two each, for those special little jobs that HSS can't cope with.

Bogs

[Divided he ad]

Looks like your having fun John 


More than a little annoying!!  But your fix sounds like it will do the job 


I'm sure we will all be waiting to see how it turns out (oh.... is that a pun??  ) 



Ralph.

[bogstandard]

Ralph,

I can come up with solutions that work rather easily, getting them done at this moment in time is the problem.

I have said that all this could be done in a good day in the shop, and it could, with ease. My problem is getting and staying in the shop for any length of time. I feel absolutely awful because I have taken so long on this project.
Once I get myself sorted (and hope I can be fixed), then little projects like this will end up as a one or two poster.

I have already had the saddle sliding on the gibs, and it was baby's bum. Once they are held in position with the screws, they should be perfect.

John