Spline Shaft

[Gaby Zenz]

Foryour convenience we have off the shelf mating broached sleeves and flanged bushings to match our Grob Standard Spline shafts. We also offer custom broaching of your parts to match with our Grob Standard Splines.

Very much a newbie here, and what makes this even worse is that I am electron push trying to work in the mechanical world. What I need for lack of a better term is to model splines around a shaft. If someone would give me some pointers to get me going that would be great. Thanks in advance.

There is no direct way in Fusion currently to create a spline curve and wrap it around a cylindrical surface. But you could use a workaround to get that - create a Coil primitive feature around the shaft in the Model workspace and then use Project geometry in the Sketch workspace to project an edge from the coil feature on to the shaft.

I would probably make shaft splines, which I'm imagining are linear groves along the shaft, by choosing Make Sketch, sketching one spline "tooth" and doing a circular pattern to repeat the rest quickly, so that a closed profile is created. Finish sketch and extrude the profile.

Thanks, that is what I ended up doing. But since your had that answer,

what I next need to do and have no luck at is, extending one spline or

another way of looking at it is not removing one spline tooth. See

attached file.

The answer to your question about whether to use Design Accelerator to create your internal/external is absolutely, use the Design Accelerator (DA). The DA will also answer your other questions about dimensional sizing of the components. Watch the Screencast and you will see how easy the process is. If you want a spline that is not listed, that will be a different story.

I also advise you to use the DA Spline Calculation feature to make sure your design will carry the required horsepower, this is also in the Screencast. One last thing, the DA will also add an angle assembly constraint to keep the components aligned.

Thanks for reply, I am having Involute spline, I am already having manufactured spline and its having issues in assembly so I would like to reproduce exact spline, so what are the measurement I needed to take on Invoulte spline shaft to reproduce exact shaft as I dont have spline drawings but only a physical shaft from customer.

If you already have the involute shaft spline in hand, determine the size, either from using the measurements from the Design Accelerator or for dimensions you probably can find on the internet. Once you find the specifications for your shaft, hopefully you will find the same involute spline in the Design Accelerator. If you do, just use the same process to just generate the internal spline. If you do not find the necessary dimensions, I would say jump back on the internet and search for involute spline dimension sheets.

If you have to model the involute spline shaft, you will be tempted to use the Derive function in Inventor to determine the female bore. BE CAREFUL, with this method, the internal bore will be exact size, metal to metal contact. If that is what you want, OK but in real life, it will probably bind.

I only have basic metal fabrication tools and do not own a mill or a lathe, but would like one. I took apart my cheap drill press to study whether or not I can convert it into a milling machine. The spindle features a 4 tooth 9mm x 9mm tooth male splined section that mates with a female splined bushing press fit into the pulley's bore (see parts numbers 62 and 71 in diagram). The entire spindle fits inside the quill tube (see part 68) creating the quill assembly (see photo below). The spline allows the spindle to extend downwards and upwards in the head casting while also allowing the spindle to rotate with maximum torque.

Currently, I am considering replacing the entire spindle with an 16mm O.D. ER20 tool holder. This will give me a more ridgit hold on the cutting tool as Jacobs Taper cannot handle axial forces required for milling. I am also planning on replacing the existing bearings with either angular contact bearings or tapered bearings.

I would like to maintain the quill's retract and extend mechanism. To do this, I will have to somehow jointhe end of the ER toolholder to a splined shaft that will fit in the female end. Currently, I can't seem to find any off the shelf spline to 16mm coupling. I am not even sure what they are called.

Are there any solutions for coupling or attaching a spline shaft to a plain old shaft? What is it called and do they exist? Finally, I am not completely married to using a spline drive mechanism in order to extend and retract the quill, so I welcome any suitable alternative mechanisms. I saw a ball spline, but wasn't sure if it works the same way as the existing mechanism.

In general, I would warn you that you aren't likely to get very good rigidity out of this system because by maintaining the quill mechanism and adding the length of the tool holder plus an extra joint (of any type) you are adding more cantilever to what sounds like already fairly sloppy tool. In addition, be warned that the manufacturer of the tool certainly won't endorse any project like this and any joint you implement yourself may fail, so you're going to be spinning a pretty heavy piece of metal pretty fast at your own risk. Personally, I wouldn't recommend it.

Firstly you could buy an adapter. Spline shaft adapters are made, but usually only for much larger shafts. In addition, I'm not sure if that spline profile will be standard or specific to your drill press manufacturer. Other people will make you a custom spline adapter, which may be expensive but would get the job done. Most reasonably equipped local machine shops could also make an adapter. The problem with connecting spline-to-spline is that with the cutting forces, you'll have significant axial and radial forces to resist. Splines are good at transmitting torque, and reasonable at resisting radial force, but don't resist axial forces at all. For that reason, pick a spline adapter design where the female spline rigidly cplamps to the spline with a thru-bolt, not one of the designs that only has a set screw.

Another strategy would be to try to develop as much clamping force on the outside of the spline shaft as you can, completely forgoing any contact with the radial faces of the spline. To do this you could use a regular shaft coupling like this or this. Standard rigid shaft couplings with different sized bores at each end are rare though, so you may still need to get one made custom. It is common to find couplings where one end is a finished bore and the other end is unfinished to allow you to bore it out yourself, but I haven't found any small enough for your application. If you do decide to do this, the bore needs to be cut by a machinist on a lathe, don't attempt to use the drill press for it.

The last option, though I'm still not confident you could find parts small enough is a taper lock shaft coupling like the Fenner RM12 shown here or the Climax C600M-9 shown here. They have compatible sizes for 9 mm and 11 mm shafts, but don't seem to make it up to 16mm in one go, so you may still need one special bushing. These type of couplers work on a taper principle, much like a collet and produce probably the strongest and most rigid clamping force of any of the options here. Because these systems are modular (the inside tapered bushing works with multiple flanges) you are most likely to be able to find the sizes you need as stock parts. I have not searched exhaustively for suppliers that may stock your specific sizes.

Overall, I think that this is a very risky idea and may well result in failure or even injury. I suspect that to join such mismatched shafts you will need a part custom-machined, which as you know is not a cheap proposition. If you do need something custom machined, you might as well get a whole new shaft machined that has the 9mm spline profile and the tool holder itself, but by the time you pay for that, you probably could have bought a small used mill with much less hassle and risk.

There are of course other options like drilling a through hole radial to the shaft and inserting a bolt or pin, or welding the two shafts together, but neither will give you nearly the rigidity or concentricity you need, and they are likely even more dangerous that the other options.

The really quick and dirty solution: weld the current chuck to the current taper. That will ensure it won't come flying off. Then you can do light milling and start making parts for a stronger/better machine without having to buy any new bits for your drill press!

I wouldn't bother throwing a lot of money at this as drill presses are generally not rigid enough to make 'good' milling machines. Any welder should be able to put some large tac-welds (I'd do four 90 degrees apart) on that in about 5 minutes which would prevent it ever coming off (be careful about doing too much welding as you don't want to introduce too much heat into the part).

Part of this is that a drill press doesn't necessarily need to be all that rigid in order to work well. With sensible work holding you can get perfectly acceptable results for general drilling with even quite a basic machine and you may very well find that any gains in rigidising the spindle are lost by the overall tolerances of the machine as a whole.

Apart form anytime else if you are prepared to do this level of modification you might well be better off spending your time refurbishing a small used lathe as that will probably give you more benefit in the long run for similar effort.

If you're not familiar with the concept, a press fit (aka interference fit) means you press a pin into a hole that is slightly smaller than the pin (creating interference between the components which holds them together). In the case of metal-to-metal were talking a size difference of few tenths' of a thousandth of an inch [.0001] to a few thousandths [.001] of an inch.

If you provide more information regarding the materials of construction (presumably some sort of hardened tool steel for the shaft, not sure about your collar) and actual dimensions (actual meaning you measured the parts with a micrometer, or other suitable measuring device, and not the nominal dimensions provided by the manufacturer or parts description) then you could use an online fit calculator such as this one provided by Engineers Edge to get an idea of the interference needed - maybe look to the FN5 class for example.

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