Thread: Groz QCTP coming together.
18th Sep 2009, 08:21 PM #1
Groz QCTP coming together.
Finaly made some headway on my quick change tool post today . I have been held up by milling machine breakdowns and guess what the good old Hafco broke down again today . The coolant pump stopped working. I ended up just putting a drum of coolant ontop of the mill and gravity feeding . Works better than the crap coolant pump that comes with the mill . At least it was still milling thats something.
Have got the block done except for the locking lever . Just using a stud and nut from my clamp kit at the moment.
Got all the dovetails cut and the five tool holder blanks are chopped off.
I settled on a modified Groz design. It works like a groz but the locking dovetail is not sawn right off. Instead it has a partial cut terminating at a 13mm hole.
This gives enough spring lock and unlock. If it gives any trouble in the future then I can always just finish the saw cut and install a hinge pin like a normal groz.
Still got some work to do but theses photos give the idea so far.
Thanks to those who helped and advised me , mainly krisfarm and DaveJ.The volume of a pizza of thickness 'a' and radius 'z' is given by pi z z a.
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19th Sep 2009, 01:48 PM #2Dave J Guest
Retromilling,Good to see you have the tool holders done it's looking great.Shame about the coolant packing it in (Hafco's great quality again ), but it always has to happen in the middle of a delicate job, like dovetails. Not long now and you will be using it, then you wont have to shim anymore tools.
I remember the two holes in the back of the cross slide, maybe the old tool post can go there as a rear tool post latter? but thats another project.
19th Sep 2009, 03:35 PM #3
You will never guess Dave what has just happened the bandsaw has broken down . I kid you not. The blade guide bearings are crook and are locking up causing the blade to jump off the wheels.
New Taiwanese bandsaw not more than 12 months old done about 20 small cuts and I got it from you know who .
Unbelievable bad luck .The volume of a pizza of thickness 'a' and radius 'z' is given by pi z z a.
19th Sep 2009, 04:02 PM #4Dave J Guest
Hi,Take the bearings off and take the oil seals out of the bearings, give them a clean out with kero of petrol regrease and put them back in, you should get a lot more running out of them then.If you want to bring them over I will do it for you and get you going again for the weekend.I did this myself and have not had any troubles since.
19th Sep 2009, 06:55 PM #5Peter
19th Sep 2009, 07:21 PM #6
Ok Dave an Wannabe I will give that a go . Thats a good idea.
When I try to spin the bearings they are getting stuck.
It got way worse when I was cutting off the tool holders and it got hot.
A bit of wax in the cut is agood idea . I wax tungsten blades when cutting alluminium . Same principle.
Thanks for the help .
I can see that I should have done a course in machine repairs not actual machining.The volume of a pizza of thickness 'a' and radius 'z' is given by pi z z a.
20th Sep 2009, 12:49 PM #7
Update to bandsaw . I cleaned the bearings like suggested and it is working better.
The blade has stopped humping for want of a better word. It' also quieter now .
My bearings have a kind of plastic (non metal) roller cage in them and no real grease that I could see.
I don't think the design will take much heat . Tomorrow I will try and buy some good quality heat resistant bearings .
One thing I did discover on my model is that one bearing support shaft is an eccentric shaft.
So once you remove the stubs and bearings you will have to resett the distance between the rollers for the blade.The volume of a pizza of thickness 'a' and radius 'z' is given by pi z z a.
20th Sep 2009, 01:40 PM #8Dave J Guest
Good to hear your up and running again, it might be cheaper buying them off Ebay.My saw has the 4 eccentric shafts so it is adjustable from both sides.Use the eccentric shafts to put just enough pressure on the blade to hold it vertical,maybe that was the problem that the factory adjusted them too tight? Plastic rolller cage sounds dodgy for bandsaw blade guides though.
21st Sep 2009, 09:32 PM #9
Retromilling,nice to see that you have made some headway with your QCTP.It looks good and I am sure you will enjoy it when you have it fully operational,sorry to hear of your bad luck with the bearings.
4th Oct 2009, 07:19 PM #10Dave J Guest
This tool post seems to be similar to yours, and thought you might be interested in having a look. It has sheet metal cover to stop chips going down the slot.Second picture down.
face plate, tool holders
5th Oct 2009, 01:22 PM #11
That's not a bad idea Dave . I thought about also making a double dovetail design that keeps the lockup lever out of the way when turning the block around to mount boring bars . However the two dovetails comming to one corner of the block create a weak spot which makes you start cutting down on the width of the dovetail to get some more meat at the corner. This starts to defeat the whole idea of gaining an extra rigid lockup. On a small lathe this would bo ok . You can see how narrow his dovetails are.
I am going to modify the locking shaft setup so it can be reversed . Not sure exactly how yet I am open to different or better ideas. I might drill the thread right out of the block and cut square recesses in each side so that a square shaft head will lock in place.
Then do the same thing on the otherside. Then machine a lever head with an internal thread and an external diameter that turns inside the circular diameter of the square recess.
This way if the lever is going to be in the way of the chuck it can be reversed .
I have done some turning with the QCTP as it is , and it makes the lathe machine much better. These AL-1000 lathes need all the rigidity you can get beause of the very high center compared to other lathes. It seems good on paper when you are reading the specs but the saddle , compound and cross slide setup is not up to the added height especially with the standard tool post.. A lot of owners will not notice untill you start comparing other lathes and how they machine . I have compared mine to several , a smaller Enco , a Victor , a Hercus and a Gassweld and they all machined better than mine. However the new toolpost has improved things quite a bit I am happy to say. I should be out milling but my back is hurting because of all the lifting of drums of coolant up onto the mill head .
I will post some more photos soon.The volume of a pizza of thickness 'a' and radius 'z' is given by pi z z a.
5th Oct 2009, 01:41 PM #12Dave J Guest
Maybe make it a taper and use somthing like a Dynabolt as it is hardened, tapered and already threaded. When you reverse it it will only take a small tap to unseat it and will sit flush to the side of the tool post when done up. Just a thought.
5th Oct 2009, 02:25 PM #13
Thats not a bad idea at all . I will think about a Dynabolt . The only possible drawback I can think of is that a taper may take too much turning to lock up .
You know how tapers don't lock to a solid stop they keep squeezing up well I think that might make the lever swing too great but then again it may not . A very short sharp taper may not be a problem. I might have to play with that idea a bit and see.The volume of a pizza of thickness 'a' and radius 'z' is given by pi z z a.
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