Tool Post Holder

Dabbler

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I hope you do well with the sharpening!

--Plunge milling works even better in steel as it minimizes the pressure on the cutting faces. Give it a try, It is really a great way to go!
Another way I just thought of: If you take very shallow cuts, you preserve most of the helix, and can conventionally mill the entire slot. something like .010 depth. (just spit ballin')

all the best!
 

pstemari

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The other point not mentioned above is that slotting at full width is rather hard on endmills in general. Taking two passes with a smaller diameter end mill, so that only one side is engaged at a time, is a much less troublesome approach.

Also, do the plunging with a twist drill, not an end mill. I'd definitely drill at least both ends, and chain drilling down the center of the slot will definitely make things easier.

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stupoty

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I always find 2 or 3 flute end mills better for full width slotting.

Stu
 

pstemari

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2 flute end mills (slot drills in Brit-speak) are definitely better for slotting. Much more room for chip evacuation.

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BaronJ

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Hi Mick,

I also watched Tom's video and noted that he was climb milling as he was going around the sides of that cutout. Now its possible he did that deliberately in order to get a good finish, however climb milling is not recommended on a light weight machine with badly adjusted gibs and some backlash. You will get the effect that you described of rattling back and forth as you were cutting.

I personally have not tried plunging into the work as shown in that video. But next time I need to remove a large amount of metal I will try it and see if the technique is useful to me.

I also touch up the ends of my milling cutters ! I built John Morans, "Four Facet" drill grinder some time ago and found that with some small adaptations I could use it to sharpen the cutter ends. I haven't made anything yet to sharpen the flutes, although I have purchased another diamond wheel for this purpose.

I was a little disappointed to hear that you have chipped the corners of a couple of cutters. Usually this is caused by re-cutting chips caught in the bottom of the slot, as is the line in the side wall of your slot. If you examine the flute edges carefully, you might find a tiny chip in the flute edge.
It is important to brush the slot clean after each run so re-cutting is greatly reduced.
 

mickri

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I brushed the slot clean after each pass because I had read about the problems caused by chips getting re-cut. I use a tooth brush to clean away the chips. I have one for the lathe and one for the mill/drill. I find that a tooth brush seems to work well for cleaning away chips.
 

martik777

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I've been using these 'norman' toolposts for years. It's much quicker if you attach a handle to tighten them. I made a few light duty ones with 1/2" steel and a welded on toolholder, the leftmost one is extended to get close to the spindle.

Get some of these 6mm carbide roughing end mills for cutting the slots. They are almost indestructible toolposts.jpg and only $5 each.

https://www.aliexpress.com/item/16mmx45mm-HRC45-Roughing-End-Mills-4-flutes-Milling-cutters-CNC-rough-EndMill-Tools-Carbide-router-bits/32801035368.html?spm=2114.search0104.3.2.e1854109aARodv&ws_ab_test=searchweb0_0,searchweb201602_5_10065_10068_10130_318_10547_319_10548_10696_450_10084_10083_10618_452_535_10139_534_533_10307_532_204_10059_10884_323_10887_100031_320_10103_448_449,searchweb201603_60,ppcSwitch_0&algo_expid=4f821837-2fe6-4737-856a-4566617d09f7-0&algo_pvid=4f821837-2fe6-4737-856a-4566617d09f7
 

Bugleone

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This is actually a Norman tool post system and a commercial version used to be made by Myford here in the UK. There is more info on the 'lathes UK' website and also here;

http://www.toolsandmods.com/lathe/mini-lathe-qctp

I first used this design 40 years ago and I am currently making a set for my new small Warco (Weiss) lathe as the Norman is vastly superior to a 4-way on small lathes where access and room are at a premium.
 

BaronJ

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Hi Guys,

I vaguely remember that ! There was something with the threaded disc under the tool block.
It stood out because the tool holder was angled forward and out towards the chuck.
 

mickri

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Spend the afternoon finishing up the last of the tool holders. They are not pretty and still need some clean up but they are done. Lots of sharp edges and corners that I will need to round over. Learned a lot making these that I don't think I would have learned as quickly if I hadn't made them. I plan to make 4 or 5 more.

IMG_3637.JPG .
 

BaronJ

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Hi Mick,

Looking very nice all lined up there !

Now you need to make the Knurling tool one :encourage:
And the flip up threading tool holder, and...:encourage:
 

mickri

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Here is my threading tool holder. Was this what you were referring to?

IMG_3638.JPG

A tool holder for my knurling tool is not high on my list. It will come in the next batch. Don't know when I will get to that. My 1966 Midget has been complaining that I am not spending much time resurrecting her so I can take her for a drive next spring/summer. After finishing getting the rest of my firewood split and stacked I plan to spend as much time as I can on my midget.

IMG_3506.JPG
 

BaronJ

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Hi Mick,

Sorry I didn't recognise the threading tool on the other picture. But yes that was what I meant.

I like the Midget ! :encourage: Is it a series A engine ? A bit of envy on my part. :encourage::encourage::encourage:
 

mickri

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The engine in the Midget was toast when I got it. It was frozen solid and had various other problems. The cost to rebuild one is exorbitant and you barely have 50 hp. I am swapping in a Toyota 3TC and 5 speed from an early 80's Corolla. It is a pretty easy swap. Only took a weekend to remove the old engine and get the 3TC in place. I am keeping the 3TC basically stock and expect to have around 80 hp. The weak point in a Midget is the rear axle shafts. They are only good for up to around 100 hp at best. There is a modification that you can do called growlerizing the axle shafts. Named after a man down in Australia who spread the modification on the web. Midget axles almost always break in the same spot. The outer edge of the spider gears in the differential rest on the splines which causes a stress point on the axle shaft. The fix is to go one inch in from the end of the shaft and turn the shaft down to the root diameter of the splines for about 4 inches then taper the next 6 inches back to the original diameter. This eliminates the stress point. A modified axle is good for up to 125 to 150 hp. See the drawing below.

spridget axle.jpg

I plan to do this mod on my lathe. Will need a taper attachment which is also on my list to make. More tooling. It never ends.
 

BaronJ

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Hi Mick,

Thank you for that info, I knew there was an issue with the rear axle, but I didn't know what it was.
I also vaguely recall a problem with the series "A" exhaust manifold.

But that isn't going to be a problem with the engine change, and another 30 HP will be welcomed. Certainly better than the 44 HP or was it 48 HP that the "A" engine produced.

In my younger days I helped with the fitting of an over bored 1600 cc BMC power unit in one. The guy who owned it gave me a ride in it one weekend ! I'll not mention brown stains, he totally terrified me. Some time after that he swapped it for a Lotus 7 kit car with a three litre Rover V6 engine in it. No way was I riding in that.
 

mickri

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Before getting the Midget I thought about a Locost 7 which is a take off of the Lotus 7. Talk about scary fast. Some of the Locost guys are putting 400 hp plus engines in a 1200 lb car. I decided building an entire car from scratch was not what I wanted to do. The Midget will be more than fast enough for me.
 

BaronJ

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Good Morning Mick,

That is frightening ! I cant imagine 400 hp in such a lightweight car. I believe the Rover engine was in the 180/200 hp range. Great on a track, but for a road car ! No, its too much.
 

mickri

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I was boring the center hole on my ER32 lathe chuck project using my large boring bar holder. The tool holder kept coming loose. I kept tightening the 1/4" clamp bolt and ultimately the bolt sheared off. This was not unexpected. I was concerned about this when I chose the 1/4 bolt but didn't think that I had the room for a larger bolt. I can think of two solutions. One I could buy a stronger 1/4 bolt. That would be the easiest solution. Or two I could try to bore a hole for a 5/16 bolt. Due to the location of 1/4 bolt hole if I just enlarge that hole I think that it will be too close to the edge of the holder. So I would need to drill the hole for the 5/16 bolt offset slightly. I don't think that I could do this with a drill even if I filled the 1/4 hole with a bolt held in place by JB WELD. Might work. Could you do this with an end mill plunging it into the holder?

Looking for suggestions.
 

BaronJ

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Hi Mick,

Yes you could move the hole using a slot drill / end mill, But you will have to make sure that your setup is sufficiently rigid. You could, if you are careful open the hole out as you move it to suit a split clamp arrangement as I showed.

But you would then have to bore inside the holder bore, to cut the radius in the pin without damaging the holder bore. Or you could just cut the radius in the pin, free style. Not difficult to do ! But takes care and time.
 

Dabbler

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a 5/16 bolt is 1.5 times stronger than a 1/4 bolt. if you went to a grd 8 bolt, and went 5/16 it would help. 3/8 would be more than twice as strong, if there's room. If they are made with 1/2" steel, you can safely go to 3/8 which will be a lot better.
 

mickri

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The the large boring bar holder is the only holder with a 1/4 bolt. It looks like I have room for a 5/16 bolt if I can offset the hole. I don't think that a 3/8 bolt will fit. I will measure it again. All of the other holders have a 3/8 bolt. If I can't successfully offset the hole then I will make another holder for the large boring bar.
 

BaronJ

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Hi Mick,

Just a thought, I've been back and looked at your pictures, if you put a saw cut in the holder one on each side of the post hole, say 50% of the material thickness, it just might allow the holder to flex more and give a slightly greater grip area.
 

mickri

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I thought about making the saw cut wider when I made the holders. I also thought about milling more of the material away so that the sides would be thinner and have more flex. I saw one picture where one side followed the curve of the center hole and looked to be 1/8" to 3/16" wide. Without a rotary table I didn't know how I could do that other than rough cut most of it away with whatever and then use a grinder to smooth it out.
 

burdickjp

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burdickjp

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Something I did on mine was offset the slitting operation so one side has more material than the other.
 

mickri

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I thought about offsetting the slot. I just went with what everybody else was doing with the slot centered. I am going to make a holder where the holder follows the curve of the post.
 

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mickri

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I enlarged the existing hole and threaded it for a 5/16 x 18 bolt. Picked up a grade 8 5/16 bolt which tightens the holder to the post. No more slippage. Looks like I got the problem solved.
 

mickri

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When I made the base of the tool post I left it flat with nothing fitting into the T slot. I have had issues with the base and post twisting under heavy cutting loads. I don't like how tight I have to tighten the base and post to keep it from twisting. I don't have any stock on hand thick enough that I can use to make a new base. My thought is to weld a piece of steel to the base and machine it to fit the T slot. Is this an acceptable solution?
 

BaronJ

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Hi Mick,

Based on your picture in post 24, I thought that you had made it so that it fitted into the "T" slot. A temporary fix might be to put a piece of paper under the plate and tighten down on that. The post on mine is 38 mm in diameter and locks solid.

With regard to indexing, I've never used it or needed to. If I want to square the holder or the tool bit, I just use the chuck face.
 
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