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Minimax T124 Copy Lathe Profile Problems

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Forum topic by nottaclu posted 08-15-2013 07:33 AM 2750 views 0 times favorited 16 replies Add to Favorites Watch
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nottaclu

9 posts in 384 days


08-15-2013 07:33 AM

Topic tags/keywords: copy lathe duplicator problems profile

Hello,
I am turning to the pros for some help as I cannot wrap my head around what is going on with my minimax t124 lathe, while trying to copy from a template. I was hoping someone on here, who has some more experience then I, could help me try to figure out what could be going on, so thanks in advance.
OK…now the issue. We just purchased this lathe and are brand new to turning. We are trying to make some wood baseball bats. I took an existing piece, took measurements and drew it up in CAD to create our profile template. The profile template was laser cut from .25” scrap steel. We turned two bats last night, one with the handle at the head stock and one with the handle at the tail. Both times the bat had a fatter handle than it should. We had the copier set to make the finished bat about 1/16th thicker to allow for sanding. The barrel, and knob of the bat came out very close…but like I said the handle was very thick…like 3/16ths. First thing I wanted to blame was the template…but i checked the measurements a billion times and they are correct.

Please ask any questions you may have, I just want to get this solved…or at least understand what is happening. Thanks!


16 replies so far

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nottaclu

9 posts in 384 days


#1 posted 08-18-2013 08:14 PM

Any thoughts?

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huff

2804 posts in 1922 days


#2 posted 08-18-2013 09:11 PM

nottaclu,

Is your duplicator guide bar following the template all the way, allowing the cutter to go deep enough to cut the narrower dia. of the handle?

It sounds like your cutter head is not allowed to follow deep enough to make the smaller cut. Are you backing your depth adjuster out a little after each pass?

-- John @ http://www.thehuffordfurnituregroup.com

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nottaclu

9 posts in 384 days


#3 posted 08-21-2013 04:23 PM

I am pretty sure I have found the issue but am still confused on how to fix it. The finishing knives we got with the machine are machined at an angle…as you can see in the 3d representation I made of it. This causes the knife point to be about 1/8th higher then the head/tail stock points, causing our turning to become distorted when getting into the more narrow handle. How should the knife line up with the head/tail stock points? I would assume that the points should meet in order to make a 1-1 copy. If that is the case how on earth would I do that with the tip of the knife cut on an angle. Thanks everyone.

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nottaclu

9 posts in 384 days


#4 posted 08-21-2013 05:23 PM

or should it be like this

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nottaclu

9 posts in 384 days


#5 posted 08-21-2013 05:51 PM

but because the cutting edge is cut at an angle….if I move the knife so it would actually make a cut to the 0 point….it would look like this

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huff

2804 posts in 1922 days


#6 posted 08-22-2013 01:55 AM

nottaclu,

You have a +plus / -minus adjustment knob on your duplicator head assembly; actually you have three controls on the ducpicator head. One is the “wheel” the moves your duplicator assemble from left to right while making your cut (it will travel the full length of your bed). Second is a handle that if you lift on it, it will releave the tension on the duplicating bar and if you twist it, it adjust the amount of dept of cut the duplicationg bar will allow the cutter to cut. And the third is a knob that is your +plus/ -minus adjustment. This allows you to make your finished piece larger or smaller then the template. This should make your entire piece either smaller or larger and not just one end (or the smaller diameter).

It sounds like maybe your tail stock and head stock is not lined up properly or you are off centered on one end of your stock your are turning.

If you didn’t get a manual with your lathe, I would suggest you try to find one on line because there are a lot in the manual on how to properly adjust everything and the proper angles to sharpen the cutter.

Your second illustration is how your cutter should look and that I believe you can adjust with your +plus/-minus knob.

How did you know where to drill the mounting holes in the template?

If your template is mounted properly in your lower carriage, then it should track equally across your entire work.

Other then that, I’m not sure what to say to help with your situation. I sold my T124 a couple years ago, so I can’t go out and take any pictures that might help show what I’m talking about.

I loved that lathe and turned many items over the years.

Good luck and feel free to drop me a PM if you would like to discuss things in more detail.

-- John @ http://www.thehuffordfurnituregroup.com

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nottaclu

9 posts in 384 days


#7 posted 08-22-2013 04:01 AM

Thats the thing. Logic is telling me that it should be like picture 2….however, like I said…since the knife edge is at an angle….we either end up with picture 1 or 3.

Were your finishing knives slanted at the ends like in the picture….or were straight? Thanks for the responce btw.
Drew

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REO

611 posts in 711 days


#8 posted 08-22-2013 08:39 AM

the knife should be as in picture two. depending on how wide your template was even cut with a laser the stress in the template could have allowed it to warp away from the cut. stand the template on edge on the bench and measure the distance between the template and the bench top. do the math and see if this could be your problem.

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huff

2804 posts in 1922 days


#9 posted 08-22-2013 08:41 AM

Drew,

My cutters looked something like you have drawn; except the actual cutter was made like a “V” shaped gouge.

I never really tried aligning my cutter to the center point of my headstock or tail stock. When I first got my lathe, I turned a pretty simply table leg with a few different profiles and diameter’s and then mounted that in my lower carriage and turned another one.

I found my +plus/-minus adjustment was a little off and made a few adjustments to zereo it out and mine seemed to work fine from that day forward.

I do know it was critical when using a template to put the mounting holes in perfect placement or it could throw things off.

One of the first projects I did ( in fact; the reason I bought the lathe) was I had to turn 69 spindles for gables in a 100 year old house.

I figured trying to turn 69 spindles and have them look anthing alike, I would need something better then trying to eyeball them by hand. lol.

Once I got it set up, I even had my 8 year old son turn a few for me.

It’s a great lathe.

-- John @ http://www.thehuffordfurnituregroup.com

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nottaclu

9 posts in 384 days


#10 posted 08-22-2013 05:23 PM

My template is laser cut from .25” scrap steel, and it is still straight. Since my cutting knife does not meet the head and tail stock point (it’s an 1/8” directly above) it’s causing the distortion when getting to the narrower radius of my template. If the points lined up this problem would be resolved, I just can’t figure out how to do it. Only way I see would be to shim the back end of the knife. I will try to get some actual pictures soon, currently on vacation. Thanks guys.
Drew

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huff

2804 posts in 1922 days


#11 posted 08-22-2013 11:04 PM

When you say your template was laser cut; is that the profile or the location of the holes in relationship to the profile. If one end of your template is mounted a little higher then the other end then it would throw the cut off from one end to the other.

If your location of the mounting holes are in perfect location in relationship to the profile itself then there should be no problem with that.

If your cutter is 1/8 higher on both the headstock point and tailstock point, then your turning should be 1/8 larger throughout the entire length of the turning? I don’t understand how it would change from one diameter to the other.

I guess I’m just as confused as you. LOL.

-- John @ http://www.thehuffordfurnituregroup.com

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nottaclu

9 posts in 384 days


#12 posted 08-23-2013 04:08 PM

The whole template was laser cut, so we have slots where the holes are. And we mount it so it is completly level compared with the billet. I believe we find that it destorts in the smaller handle becuase when we start the turning, we have a reference point on our template that matches the max size of the billet…so we use the + and – wheel to bring the cutting knife into the edge of the billet….then as we dig in we start to swing into the 1/8th over. When I get home I will try to find a way to align those two points and I believe all will be fixed. However, not so sure how to do that. Huff, when I get back home I may send you a video so you can better see how our machine lines everything up. Thanks.

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huff

2804 posts in 1922 days


#13 posted 08-23-2013 04:50 PM

Look forward to the video and the cure for the problem. It’s probably something simple we’re both missing. lol

-- John @ http://www.thehuffordfurnituregroup.com

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trendready

1 post in 253 days


#14 posted 12-23-2013 06:16 PM

If the end of your template is square, the stylus will initially ride the top edge of the template. As the profile narrows, the stylus will rotate to the lower edge of the template and this will cause an error.

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nottaclu

9 posts in 384 days


#15 posted 12-23-2013 11:29 PM

Yep we figured out what was happening. We simply put the template on the top side of the holder, and now our duplicating arm rides on the bottom edge of our template the whole way.

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