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ShawnR
02-20-2013, 08:51 AM
I have been lurking here for awhile and enjoy the site. Thank You to those that support it and contribute to it. It is time for me ask something.....

I have a Craftex lathe http://www.busybeetools.com/products/LATHE-METAL-10IN.-X-18IN.-3%7B47%7D4-HP-CRAFTEX.html

I also have a 4 jaw chuck that I have never mounted...forgot I had it till I found it the other day.:o The lathe spindle has a plate on it that the chuck bolts to. Picture a pipe with a plate on it, all one piece.

In order to use this 4 jaw chuck, I need an adapter plate. Busy Bee does sell them http://www.busybeetools.com/products/ADAPTOR-FOR-4-JAW-CHUCK.html but it seems that I should be able to make one and could certainly use the experience...

So, my questions are ..should I tackle this? The reason I hesitate is that since this sets up all future jobs in the 4 jaw, maybe too crucial a fixture to attempt for a not so experienced guy?

The holes on the plate obviously have to line up with the chuck plate and other holes, line up with the chuck mounting holes. Is this what transfer punches are for? I would guess I could simply drill through the two chucks mounting holes (carefully so as not to damage threads of course)? I was thinking line the plate and first chuck up, drill one hole, tap it, bolt it, lightly, then drill next, repeat. This should ensure they all line up, although kind of crude versus laying out and measuring. ...?

How thick should the plate be, given that the adapter mounts to the spindle and then the chuck mounts to it, the bolts need enough thread to hold well. Would a 1/2" plate be enough? Start with 3/4"? I think the bolts that hold the chuck on now are about 3/8". (metric version of that....9 mm? I can check later. I have never had the 3 jaw off,...always being afraid of not getting it back on perfectly, but maybe I do not have enough faith in the lathe builders..... I do have a dial indicator so it should not be an issue. I would like to venture into other uses for the lathe and I also have a large face plate that might come in handy, although I will need some clamping hardware for this....another thread maybe...:-)

Or should I suck it up and buy the adpater plate? They are pretty reasonable$ and the one review states it worked well, ..... but ordering that one part leads to the "might as well order too" syndrome so the plate will become quite expensive :rolleyes:

Gary Paine
02-20-2013, 03:56 PM
The lathe spindle has a plate on it that the chuck bolts to. Picture a pipe with a plate on it, all one piece.

You've got me here. I'm not familiar with the lathe, but I can't imagine it designed as you describe. It would have cost a lot to machine a spindle out of a big bar. How do you remove the chuck normally? Do you somehow remove the screws between the adapter and chuck and adapter stays?




The holes on the plate obviously have to line up with the chuck plate and other holes, line up with the chuck mounting holes. Is this what transfer punches are for? I would guess I could simply drill through the two chucks mounting holes (carefully so as not to damage threads of course)? I was thinking line the plate and first chuck up, drill one hole, tap it, bolt it, lightly, then drill next, repeat. This should ensure they all line up, although kind of crude versus laying out and measuring. ...?

How thick should the plate be, given that the adapter mounts to the spindle and then the chuck mounts to it, the bolts need enough thread to hold well. Would a 1/2" plate be enough? Start with 3/4"? I think the bolts that hold the chuck on now are about 3/8". (metric version of that....9 mm? I can check later. I have never had the 3 jaw off,...always being afraid of not getting it back on perfectly, .............

In the photo of the adapter plate you see a thicker portion of the plate inside the mounting holes. That is the register surface for the chuck and is the only real critical part of the job. A plate, 1/2 inch should be plenty thick, would be fitted to the lathe spindle through whatever fitment is on the spindle. It then should be turned true in the lathe with OD to match the chuck and face true to the lathe. Now cut the register. The register needs to be exactly the right diameter to fit perfectly into the recess in the back of your chuck. The mounting holes are just clearance holes and do not control the fit, the register does that. I have found that the best results come when the adapter is machined right in the lathe where it will be used rather than reliance on manufacturing tolerances.
It should be a straightforward project and I think you will enjoy it.

JohnAlex141r
02-20-2013, 04:39 PM
Hi Shawn;

I have made backplates for an Emco Compact-8. Same size lathe. No problem. Is the smaller flange tapered or straight? The EMCO is tapered, some others are straight sided.

What I did was mount a circle of steel (or, cast iron, for my faceplate) in the 3-jaw chuck, bore it out until close to required dimension, then, REMOVE 3-jaw from lathe, and try the back plate on it. If it won't fit, bolt the 3-jaw back on, and you should be able to skim another bit off of the bore.

If you remove the disc from the 3-jaw, you'll have real difficulty when getting close to the dimension required, because it will not go back onto the 3-jaw accurately.

You need the bore to be a nice slide/no shake fit, and the back of the back plate turned flat.

If there are studs on the backplate: I made an adapter that would fit in the bolt-holes in the spindle (bit of turned steel, easy) with a hole through the centre just big enough to put a nail in. It made "Scratching" the backplate to get the bolt-circle radius easy; drill/tap one hole, then I did the others.

After the back plate is made, and is CLEAN, then mount it, turn it so that it fits your 4-jaw.

It's all pretty easy turning; getting the bore correct is a good thing to try. If you fail, you can either try again, or simply buy the backplate from Busy Bee!

Make sense?

Another JohnS.

Bob Fisher
02-20-2013, 05:48 PM
Is this one of the lathes that has " bolt-on" chucks? If so, transfer punches will be Ok. It is, after all, a 4 jaw, and by it's very nature can be centered in spite of your inaccuracies. Just make sure the mounting surface runs true. Bob.

ShawnR
02-21-2013, 08:02 AM
Thanks for the replies. After I posted yesterday, I went to the shop and ended up taking the chuck off. I have never done this. Never really needed to but always hesitated. I see the register surface and see what I have to do. If the bolt holes are all clearance only, then drilling should be no problem. I also have a back plate and those holes go through so marking the new plate should be easy enough. My plan is to cut (burn) the steel sort of round from a piece of flat I have. Then grind the edges to get rid of slag, then find holes for mounting, drill and tap them to mount on lathe, as it will be when finished. I can then turn the surfaces, fip it over when the register surface is complete and turn the chuck side.
Sound right? Yes, having seen what I have to do, it does sound like a fun project as Gary says. And Bob is right, if I miss on my tolerances, then do it again until I get it right! :-)

Thanks. I will report back.

ShawnR
02-21-2013, 11:45 PM
I cut out the plate today. Will start machining tomorrow
http://i1359.photobucket.com/albums/q786/ShawnR6/Lathe%20adapter%20plate/roughplate_zps6c88ba4f.jpg
1/2" material

http://i1359.photobucket.com/albums/q786/ShawnR6/Lathe%20adapter%20plate/spindle_zps7dd4a6c8.jpg
Spindle and plate all one piece.

http://i1359.photobucket.com/albums/q786/ShawnR6/Lathe%20adapter%20plate/chuckbacks_zps838b847e.jpg
Comparing backs of two chucks. Register surfaces are same size, just 3 holes versus 4

http://i1359.photobucket.com/albums/q786/ShawnR6/Lathe%20adapter%20plate/spindlemount_zps11eee052.jpg
Spindle shot again

michigan doug
02-22-2013, 03:23 PM
Yup, nice project. Not overly complicated. Immediately useful. Saves a bit of money to be used elsewhere. Not overly critical dimensions. Even if your critical registration is off by a thou or two, the workpiece gets dialed to be concentric with the true axis of rotation anyway, more or less.

If you haven't used a four jaw much, it will be tedious to get things properly centered the first ten times. Do yourself a favor and leave it on and use it exclusively for 6 months. Unless you have to use a 3 jaw or a faceplate for something else, then go right back to the 4 jaw. It will become natural and efficient to center the workpiece.

Finest regards,

doug

thebigron
02-22-2013, 08:16 PM
I concur with Michigan Doug on leaving the chuck on the lathe for a while. You might even never use your universal again. When I bought my 15" Clausing back in 07 the three jaw chuck that was mounted would never repeat with round stock well enough to suit. I slipped the independent on and was slow the first 10-20 pieces but today in everyday use it is second nature with me. I remounted the three jaw chuck back a year ago, but it did not stay on very long; first time I needed accuracy or the fourth jaw it was back in the cabinet. Good luck with your lathe and stay tuned, these people here have a vast wealth of information and will help you at every "turn". (Intended pun)

ShawnR
03-05-2013, 10:19 AM
Well, learned lots. I am not the handiest with a torch, I gave myself lots of room so as not to burn into circle and ended up milling a LOT of metal off. Could be a long story but this plate took a long time. I could not make it in the industry...;-) My first mistake (and largest) I think was drilling a hole in the middle(ish) of the plate to mount a mandrel (which I had to do when I realized a bolt and nut is not secure enough) before I made all of my mounting holes. I lost that centre. I then made a plug to represent the register on the lathe so that I could test fit the adapter before removing it from the late. However, a little practice is needed here and so I ended up remounting and realigning the plate several times before it fit. On a good note, it does fit very well, maybe a little snug but I figure better than loose. I found that when I went to drill the 4 holes to mount the chuck to (through holes, clearance holes someone called them earlier) I missed a bit and it was either scrap it or grind a little so I chose to grind. Had I done all of my holes (3 for 3 jaw, and 4 for four jaw) before I did any other milling, it would have been much easier to get them all aligned I think.

So now I have the adapter on the chuck but the finished thickness is about 0.370. I need to recess the fasteners, which, cap screws are 0.275 so that does not leave much material. I am thinking I need to get some grade 8 bolts and shave the heads down slightly but how much can I get away with? Split it, ie, 0.180 of material in plate and about 0.180 of fastener head? Or is this just too thin and should I start again?

This is a 10" lathe so not large and there are 4 fasteners but I don't have any idea of how much these can support. I would think more than I will ever need but thought I would check with you guys....?
The alternative is to start again, with a thicker piece of stock. I started with 1/2" material and the register needed about 0.130 so that is what is left.

Photos (cause we all like photos...;-) )

Lots of milling due to lack of good torch skills
http://i1359.photobucket.com/albums/q786/ShawnR6/Lathe%20adapter%20plate/IMG_3672_zps2f74f7e4.jpg

Registers
http://i1359.photobucket.com/albums/q786/ShawnR6/Lathe%20adapter%20plate/IMG_3673_zpsd85a777d.jpg

Mounted, finally after 3 remounts! Gotta work on measuring, cutting and confidence skills :-)
http://i1359.photobucket.com/albums/q786/ShawnR6/Lathe%20adapter%20plate/IMG_3676_zpsf454eed8.jpg

Fasteners
http://i1359.photobucket.com/albums/q786/ShawnR6/Lathe%20adapter%20plate/Plate_zpsdbb618e8.jpg

Deja Vu
03-05-2013, 11:48 AM
You might be able to use flathead screws countersunk to be flush(or slightly indented) with the plate. Preferably hexhead drive rather than sloted.
http://shantibolts.com/images/flat_head_socket_cap_screw.jpg

ShawnR
03-05-2013, 01:40 PM
You might be able to use flathead screws countersunk to be flush(or slightly indented) with the plate. Preferably hexhead drive rather than sloted.


Thanks. I was just in town, trying to find such fasteners, but in my area......not much luck so far. I think that is the direction I will go but may have to wait.

gcude
03-05-2013, 02:13 PM
Thanks. I was just in town, trying to find such fasteners, but in my area......not much luck so far. I think that is the direction I will go but may have to wait.

Ace Hardware stores in my area have a good selection of fasteners, including ones like those shown. They are my goto for gotta-have-it-now. If I can wait a couple days, I buy from Mcmaster-Carr.

Mcgyver
03-05-2013, 02:54 PM
I'm a bit lost here....anyone know what type of spindle mount that lathe has?

RussZHC
03-05-2013, 03:19 PM
Mcgyver: I could be mistaken, the second photo in post # 6...this is one of those lathes which, in usual terms, sort of has no spindle mount...the spindle has a extra-ordinarily large end (all one piece, none of the usual screw or other mounting systems) so, going by what the Craftex/Busy Bee manuals suggest is if the fit is poor you take a chance turning down said end to make it more exact PLUS, if you have a second chuck the female register on it would need to be the exact same.
This route is to put another sort of adapter plate in-between if you don't want to chance machining the spindle large end wrong [there is sort of a locking ring and bolts that go through the spindle "plate" directly into the back of a chuck]

Juergenwt
03-05-2013, 04:59 PM
I would buy an adapter plate that is made to fit the spindle on your lathe. Put it on the spindle and than finish the front part to fit your 4-jaw chuck.
Otherwise if you make it yourselves you will need to make a replica of your spindle nose first. Than make the blank to fit the replica of the spindle nose.Than proceed as above.
The way JohnAlex posted will work if it's easy to remove the mounted chuck with the new adapter plate to try it on the spindle.
We used to keep a replica of the spindle noses of all of our machine in the tool room. That way it was easy for us to make a special mounting plate for turning or grinding fixtures to be used in the shop.

rohart
03-05-2013, 07:55 PM
If you don't fancy cutting the deep 90 deg countersinks you'll need for the screws above, you could have a look at button cap head screws. The heads on those are a lot shallower than standard socket cap heads, or Allen screws.

ShawnR
04-21-2013, 12:12 PM
In looking at a recent thread on projects (http://bbs.homeshopmachinist.net/threads/58915-Why-so-few-project-threads) , I am reminded to update this thread I started.

No photos, as I cut some corners and am not happy with the result. I could not locate the fasteners I wanted (countersunk) so modified some M8 machine screws. This cut too close to the register,....and it kind of went south from there..... ;-( I have since managed to get the fasteners I wanted originally, so will most likely try to improve it.)

I have used it, and it is "OK" by backyards standards (my norm) , not machinist standards (new to me :-) ) so I will either live with it, or try again, or maybe fix it but this will involve welding up the holes I made and starting again from there. This might not be so bad. More experience but more time.

I did try to leave the set up on the lathe for a while, as advised here, but quickly learned that I prefer a three jaw self centering chuck...no surprise. The setting up was getting more efficient as I hung with it for a while.

However, I did manage to get the job done that I needed the 4 jaw for so it is not a total loss, so on that note, I guess this project was a success :D

What I learned..? Lots! but mostly ...I have lots to learn....

Tony Ennis
04-21-2013, 01:05 PM
If you don't like the holes your drilled, just rotate the backplate on the chuck and make new ones. If you have the capability of filling in the old holes, that's cool too.

whateg01
04-21-2013, 05:42 PM
The screw holes extending into the register shouldn't be a problem. Theoretically, one only needs 3 points of contact to locate a part, anyway.

Here is an adapter plate I made to avoid altering the backplate for my 3-jaw until after I got the spindle runout addressed.
http://i97.photobucket.com/albums/l220/whateg01/tools/lathe/adapter_0.jpg (http://s97.photobucket.com/user/whateg01/media/tools/lathe/adapter_0.jpg.html)

This was about 3/4" thick overall, with the register being about 0.050" tall. Worked just fine for many months.

You'll notice 2 sets of holes. One was used with the backplate turned around backward to cut the recess for the register on the original backplate. Then flip it and face for the chuck. This is before I figured out that I could probably have used the same set of holes for both. It also had a 3rd set of holes drilled and tapped to attach the chuck.

Dave