# I want to cut my first gear



## devils4ever (Aug 14, 2022)

Hi all,

I've been looking for a first project that involves cutting gears and I found one. I'm a homebrewer and want to build a bench bottle capper. I know I could buy one cheaper, but I want a project involving gears.

I've been designing this in FreeCad, but I'm not sure what gear parameters I should use. I have a PM25 mill and dividing head. I plan on buying the rack since I don't have the tools to make a long (~12") rack. I want to only cut the pinion.

Questions:

Should I use imperial (DP) or metric (module)? Metric cutters seems slightly easier to obtain?
What pitch should I use?
How many teeth?
Pressure angle = 20 or 14.5? PA=20 seems to be for new designs?
I've been playing with this in FreeCad and it seems M1.5 or DP16 or DP20 is about right? For number of teeth, I'm thinking 24 seems about right?

As to formulae, assuming DP20, N=24:
OD = (N+2)/DP = (24+2)/20 = 1.300"

I see some differences when calculating the depth of cut depending on the PA:

*From "Gears and Gear Cutting" by Ivan Law:*
Depth of cut = 2.157/DP = 2.157/20 = 0.1079"

*From Machinery's Handbook, 25th edition (page 1930):*
Minimum Whole Depth = 2.157/DP = 2.157/20 = 0.1079" for PA=14.5
*From Machinery's Handbook, 25th edition (page 1925):*
Whole Depth (preferred) = 2.250/DP = 2.250/20 = 0.1125" for PA=20

All comments would be appreciated.


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## Alexander McGilton (Aug 14, 2022)

I had a request like this at work a year ago or so. They needed a machine to that would turn this white chemical powder into tablet pills. They would then add them to a chemistry experiment and science happens. They needed upwards of a thousand tablets per month and only one grad student to operate the machine. The machine they drew up was a complex machine to dispense and weigh powder, then press them. Thousands of dollars and many hours making a frame and rack and pinion from scratch. I said this looks a lot like a reloading bench. I emailed them photos and a few cataloger pages. I suggested that they buy a powder dispenser kit and a swaging press. Since no components were specific to a cartridge, there was no need for a firearms license. Then I would make only a punch and die of 316ss for the tablet with an ejector pin looking like a firing pin. Less than 1k$ with a wooden bench. I know that there is an anti-gun culture in Canada, didn't realize that it extended this far. So the prior plan was used, only I got rack an pinion from Master and such.    

Tangent over. 

20* and 25* Pa are for strength in a compact space, 14.5* Pa are for running with the least friction.

You can make your own rack. Square or rectangular cold roll in the vise, then cut slots with one of the below cutters. Be careful that the round bottom is sufficiently deep and the 20* walls extend deeper then the contact surface of the rack teeth. 





For the gear. Do you have a lathe change gear or a scrap gear lying around of a corresponding Dp or module of your choice? Can even be a close yet wrong tooth count. Once you have borrowed gear, hand grind a Hss blank to fit the gap between the teeth. Hold the tool and gear to the light to judge the gap. Place the Hss blank in a horizontal fly cutter.  

Rack and pinion are more forgiving of less than ideal shape than gear on gear, particularly in an application low speed and few cycles.  



Photo credit, and more reading






						Products - Milling Tools - End Mills - Tapered End Mills - Page 1 - All Industrial Tool Supply
					






					allindustrial.com
				











						Gear Tooth Cutter Holder - Sherline Products
					






					www.sherline.com


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## Alexander McGilton (Aug 14, 2022)

If you are looking for the strange flat radial fly cutter like the Sherline. You can buy one of the above, then mill the tool blank seat flat to remove the angle inherent. then add another taped hole and set screw. They are heard but not too hard. 1/4-3/8 carbide standard end mill no problem.


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## devils4ever (Aug 14, 2022)

Wow! I like the idea of using an angled end mill for the rack. That gives unlimited lengths. Is the included angle 20 degrees? Is that what I'm looking for?

I may just buy the cutter for the pinion. I'm not sure I can create my own.

Any thoughts on my questions above? Imperial vs metric? Number of teeth? DP/module?


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## Alexander McGilton (Aug 14, 2022)




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## WobblyHand (Aug 14, 2022)

devils4ever said:


> Wow! I like the idea of using an angled end mill for the rack. That gives unlimited lengths. Is the included angle 20 degrees? Is that what I'm looking for?
> 
> I may just buy the cutter for the pinion. I'm not sure I can create my own.
> 
> Any thoughts on my questions above? Imperial vs metric? Number of teeth? DP/module?


Module gear cutters are relatively inexpensive.  Probably can get a whole set in in M1.5 for $80.  Just checked - yeah you can, at least on fleaBay.  Kind of hard to cut the rack that way, but, using a shaped endmill like above fixes that issue.  You will need to make or buy a gear cutter arbor, but that's not an issue.


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## Alexander McGilton (Aug 14, 2022)

Buy a pinion not the cutter, look in repair parts not necessarily an off the shelf generic gear.  

Imperial vs metric? Number of teeth? DP/module?

Before asking that, lets determine what your mechanical requirements are. How much load and Travel is needed to cap a bottle, length of handle throw, force on handle, etc? We want this not to break on first pull of the handle and also not to be so massive to be expensive and time consuming to make.


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## Alexander McGilton (Aug 14, 2022)

Fleabay indeed. 
I ordered a set as you mentioned. The laser engraving was indicative of a proper set, though the profile of one cutter was duplicate of the adjacent one.


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## WobblyHand (Aug 14, 2022)

Alexander McGilton said:


> Fleabay indeed.
> I ordered a set as you mentioned. The laser engraving was indicative of a proper set, though the profile of one cutter was duplicate of the adjacent one.


Playing the fleabay game, is well a crap shoot.  98+% of the time you come out ahead, at least that has been my experience.  If you absolutely have to get it right the first time and you are rushed - then you have to buy "commercial" and pay the man.  If you have some luxury of time, fleabay is worth a shot.  My opinion.  Have I had to return stuff, yes.  Have I been "screwed over", a couple of times.  Still way ahead of the game.  In my opinion, if places like fleabay didn't exist, I wouldn't be in the game at all.  Can't afford "retail" on a regular basis.  Your experience may vary.


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## Alexander McGilton (Aug 14, 2022)

I'm no stranger to buying items of unknown origin and quality. I have purchased everything from cast iron cook wear, coffee accessories,  to camping supplies, and scientific glass wear from aliexpress. And yes it is a mixed bag. What I learned and using some of my privileges and mistakes from my work place. Cast iron sometimes has an exsesive amount of lead, lead lowers the melting point of recycling iron, presumably add some car batteris to the cruseble, less coal needed to make those Dutch ovens. Gl45 media bottle may say they take the full 1.5bar, then explode over the weekend under pressuer since the walls are thinner then advertised. Camping stove? Just replace the fuel orifice from 1.2mm to 0.90mm and it will burn 87 octain without smoke.


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## Bi11Hudson (Aug 14, 2022)

Having found your post an hour or so after it was posted, I wanted to give it some thought and take a nap before answering. You obviously know what you're doing, to some extent. So my first question is if you already have a machine. Either a lathe or a mill, it doesn't matter. It's simply to point you in the right direction. I have a Craftsman lathe (Atlas build) as well as an Asian machine. (Grizzly) The Atlas machine has 16DP 14-1/2*PA gears. The Asian has Modulus 1 (25.4 DP) 20*PA. As it happens, I also run an Atlas mill, 24DP (I think) and an Asian vertical mill which also has Mod.1 gears. The point is to study your machine(s) and use the same gear pattern. Even Asian gear cutters from eBay cost a pretty penny for a set. You want something that will be useful in the future.

I would prefer a smaller gear (~Mod.1) for a benchtop machine. 16 DP gears are large enough to be cumbersome for a small (less than wheelbarrow sized) project. It all depends on what, if any, machines you already have. Pressure angle (PA) is a matter of what gear you decide on. Diametrical gears more commonly use 14-1/2 degrees for lower friction. Modulus gears more commonly use 20 degrees for strength. Like above, it would depend on your own machine(s) as reference. Gear cutters can be found for more esoteric pressure angles, but the cost can be *much* higher. I'd say stick to the more common design for cost savings alone.

Some time back, I repaired a "lemon squeezer" for a friend that had a small cafe'. Your project sounds a lot like that one. The gear was (probably) a Mod.1.25, call it 18 or 20 DP. All I remember was the gears were smaller than my Atlas and larger than my Asian machine. I made the replacement the hard way (without a cutter) from brass. I don't know how it stood up. I have a small (1/2 Ton) arbor press. It has a rack and pinion about the size of my Atlas lathe, but I figure it's metric. In any case, it would be way over kill for a capper. I would say look to eBay for a "button press" as a starter idea. The price I saw was low enough to make a good pattern.

Material is another concern of relevance. Gears can be made from paper, wood, plastic, non-ferrous metal, all the way up to steel alloys. I worked with a fellow that was building a replica clock from paper. Gluing up a sheet at a time to make the gears. But for automotive steering, one would want high quality steel. For the first timer, aluminium would be a good choice for something not critical. Fairly cheap, and easy  to work. And easy to make another when you make a mistake. My Atlas has some plastic thread cutting gears, and some ZAMAK. External gears are ZAMAK, internal(read high load) gears are steel. Some may be cast iron, I don't know and it really doesn't matter.

Cutting a rack has some off the wall requirements regarding length. There have been several methods given above. There's a lot of knowledge on this site. If I needed a custom rack, I would build it on my shaper, using an involute cutter in a custom made tool holder. You're on your own there. I have a large quantity of racks salvaged from the aircraft industry. I don't know the tooth size but I suspect they are metric. They appear to be Mod.1, but I've never used one so never pursued it any further. Just a situation where they were cheap because they weren't selling. I might need one some day, or Wife will sell for scrap when I don't matter any more.

.


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## devils4ever (Aug 14, 2022)

It's hard to determine the actual force required to crimp a cap on a bottle, but it's a decent amount. I have a hand capper and with the leverage advantage, it requires quite a push.

Here's a commercial version in action. I would estimate the arm goes through 120 degrees of swing, the ram moves up and down 1/2" to 3/4", and the arm length is about 12" to 16".

Let me take whack at this.

So, taking the minimum arm length that's 120/360 * 12" * pi = 12.5" of motion on the arm. The ratio would be 12" / (3/4") = 16:1. So, 1 to 2 lbs of force on the arm would give 16 to 32 lbs of force on the ram and capper. Sound right?

I think this means the ram needs to move 3/4" in 1/3 of the pinion's rotation.
PD = pitch diameter
DP = diametral pitch
N = number of teeth
OD = outer diameter

pi * PD * 1/3 = 3/4"
or
PD = 3/4" / (1/3 * pi) = .72"

DP = N/PD
or
PD = N/DP

For N=14, DP=20, PD=0.7000"
For N=16, DP=22, PD=0.7272"
For N=20, DP=28, PD=0.7143"

I believe these calculations are correct.


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## devils4ever (Aug 15, 2022)

So, I was thinking of going with a DP of 20 or 22 with a 14.5* pressure angle. However, when I look at the tapered endmills listed on the All Industrial website, I don't see a 14.5* per side EM listed. They do have a 15* per side EM. Is that close enough or should I stick with 20*?


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## Larry$ (Aug 15, 2022)

It isn't that hard to grind a cutter by eyeballing it to a known gear sample. May not be perfect but it works. I made an arbor for mine rather than using a fly cutter. Has the tool sticking out @ 90° rather than at an angle. 
As a test I just used my spin indexer to see if the gear worked. Quick & easy setup. Used a piece of unknown plastic for the test gear. Next test was using my rotary table to get the correct # or teeth. The bulk of the RT is a problem & requires using a tail stock support. Keeping track of positions, # of turns etc. slowed progress as did using aluminum for the test gear. After quite a bit of running as a change gear I could see the wear marks showed less than ideal shape but it seemed to work fine. I've had an indexing head on order for quite some time. Due in September. 

For cutting a rack you could grind a D bit but I think it would be difficult without a tool & cutter grinder. I've done it "semi" successfully on the tool & cutter grinder.  I'm going to try it with O1 steel and the indexing head when it comes. Just to see if I can.


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## Ischgl99 (Aug 15, 2022)

Whether to do module or imperial probably would depend on which you expect to have future uses for.  If your lathe is older and uses imperial gears, you might want to go that route, but with most more modern equipment being made in Asia, it most likely has module gears.  This applies to any kind of equipment and not just lathes.  Personally, I do just about everything in metric, so I would get module cutters of the appropriate size.  Regardless of which you choose, the size calculations will be the same to calculate the torque they need to transmit.  As far as pressure angle, 20 degrees is the modern standard, so that is what I would go with so that if you buy cutters, they are more likely to be used again in the future.

Here is an alternative, this video shows cutting a gear with just a slitting saw.


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## devils4ever (Aug 16, 2022)

Okay, I think I'm going with a metric gear instead of imperial gears based on the fact that I have a mini-lathe with metric gears (M1) and the PA is 20 which is easier to find tapered end mills for cutting the rack.

Current design thoughts are:
M1.25
N=18
PD=22.5mm=.886"
OD=(N+2)/DP=(N+2)/(25.4/M)=M(N+2)/25.4=0.984"

This will give me a little more ram travel at the expense of less force which I don't think I need.

So, does anyone have a good source for metric gear cutters? I see a lot on eBay coming from China. Are these decent? I've read a lot of people who order these get missing and duplicate cutters for the set. 

Also, who makes an R8 arbor for these?


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## Alexander McGilton (Aug 16, 2022)

Gear Cutters | Wholesale Tool
					

Over 60 years in the business, with warehouses located in Warren, Michigan and Tulsa, Oklahoma. Place your order now via phone, fax, or the web at www.wttool.




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						McMaster-Carr
					

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I will write with more detail tonight


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## dewbane (Aug 16, 2022)

I just searched "involute gear cutters" on Amazon on eBay, and returned a variety of complete sets in a few select sizes, selling for prices between $60 and $120. I looked at Shars and MSC, and couldn't even find involute gear cutters. I found some at McMaster-Carr, but only in a handful of DP sizes, ranging in price from $72 to $155 *per cutter*. Then I tried Travers Tool Co. They have the best selection I've found by far. They have a bunch of metric cutters They have M1.25 in both 14.5° and 20° for about $100 *per cutter*. You can even get DP2 cutters if you want to repair a steam locomotive or something, and those will set you back $560 *per cutter*.

Since you're doing a specific project where you only need one gear, you could actually get away with buying just the one cutter you need. Pay $100 for a known really good cutter, plus whatever you come up with for an arbor. Or you could get an entire set of Chinese mystery cutters that are probably good enough for the same money.

I've never done anything sufficiently critical to justify spending the kind of money it costs to buy the good stuff, so I plan projects based on whatever sizes are actually available. On eBay right now, one option is a M1.25  20° set for $88 plus shipping, direct from China. I'll leave it to you to dig deeper.

McMaster-Carr lists a lot of different parameters for these things. Two different keyway widths, two different arbor hole diameters, and maybe other stuff. I don't understand some of the parameters. You'll need to match an arbor to whatever you end up with.

I got a set of DP16 14.5° cutters off Amazon with a matching arbor included. I just got some cheap random set to try my hand at making gears. The gears I'm actually going to be making for a project have cycloidal teeth, and I have to grind my own cutters. I haven't yet thunk up a use for any gear I could cut with these off the shelf involute gear cutters, so I haven't really gone to school on that stuff, and can't give you much guidance selecting or making an arbor.


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## devils4ever (Aug 16, 2022)

Yeah, you are correct. It is hard to find a supplier that sells gear cutters. I looked at the same suppliers and found Travers the most broad, complete selection. MC has a very limited amount of gear cutters.

I guess gear cutters are not high selling. I might want to go with Travers for the one cutter I need and bite the bullet on price. I'm hesitant of buying from China although I have done it in the pass with success.


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## tq60 (Aug 16, 2022)

I have some racks of unknown specifics, similar to what is used on lathe bedways an drill press tables.

They are listed in the for sale area.



Sent from my SM-G781V using Tapatalk


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## Alexander McGilton (Aug 17, 2022)

Alexander McGilton said:


> I will write with more detail tonight



Sorry for delay, the posts above effective said what I would have said about buying options. One benefit of making a low speed press as your first project with gears, is that the mechanics are very forgiving. You aren't giving this a 100k mile powertrain warranty so the involute profile need not be exact. In regard of craftsmanship and what to make or buy. You may as well cut your own pinion. Indexing precise components is an intimidating yet rewarding experience. Also you may want to later change the pinion to a larger diameter if you find that the retract takes too many revolutions and the forces is needlessly minimal. 

For making the rack, if you go about those tapered end mills, don't rely on Z zero being a function tool tip contact and depth. like a thread, take a shallow progression of cuts place a reference pin between the tooth flanks and measure to rack back surface to pin tangent, then machine to full depth. 









						Dimension Over Two Balls | WENZEL America
					

The standard parameters that are output when inspecting a gear are helix, profile, pitch, and runout. However, I find almost every customer asks for an additional parameter to be output – dimension over two balls (or pins). In this blog, I explain what this measurement entails as well as why it...




					www.wenzelamerica.com


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## devils4ever (Aug 17, 2022)

Yeah, I really would like to make both the rack and the pinion and not buy them. That's the point of this project.

Like mentioned previously, I'm thinking of going with:
M = 1.25
N = 16
PA = 20
OD = 0.8858"
PD = 0.7874"
D+f = 0.1062"

I might go with the Chinese cutters in case I need to change N on another iteration.

I like your idea of using pins on the rack to measure depth. I have a complete set of gage pins. I just need to figure out what size pin and what measurement I'm shooting for.

Since this project involves filling and capping beer bottle, I plan on using aluminum as much as possible with some SS hardware. I don't think I will wear this out not using steel. Brass with the pinion and rack would be better, but much more money.

I'm still working on the design in FreeCad, but I will post an assembly drawing when it's almost done.


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## dewbane (Aug 17, 2022)

I think the selection of cutters is limited, because involute gear cutters are pretty much a small shop or hobby item today.

Another thing to consider in a potentially wet, potentially corrosive environment is that brass doesn't play nice with steel. I no longer remember the specifics, or what reference I used, but there was a chart rating various metal on metal interactions. Brass + steel was the worst combination on the chart. Aluminum + steel was much better, which is a fact that is supported by millions of engine blocks.

If you do a little homework, you can probably find an aluminum alloy that would stand up almost as well as steel in this application.


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## devils4ever (Aug 17, 2022)

How's brass and aluminum combo?


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## Alexander McGilton (Aug 17, 2022)

If you go about anodizing your aluminum parts, you can get some reasonably good color combos. I don't recommend anodizing your self on the first try, not to say you cant anodize in the garage. Just getting an even color and thickness is a learning process in its self. Having an item like a taig lathe in size shape and choice of color or the suspension components on a FSAE car anodized professional is often cheaper than the express shipping to and from of said components.









						The Taig Lathe – technitoys.com
					






					technitoys.com
				







			https://blogs.mcgill.ca/fsae/


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## devils4ever (Aug 18, 2022)

I ordered a set of cutters from China. Hopefully, I'll get a complete set of decent quality in a reasonable amount of time.

I also ordered the tapered end mills from All Industrial.

I'm looking at R8 arbors now for the gear cutters. I think this will work: R8 22mm shank arbor. It doesn't state if there is a key in it, but I think the 22mm diameter matches the bore size on the cutters.


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## Alexander McGilton (Aug 18, 2022)

YH-KE Lathe High Hardness 45 Steel R8 Shank 22Mm Milling Arbor Gear Mill Cutter Tool Holder Lathe CNC Cutting Tools : Amazon.ca: Industrial & Scientific
					

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Shop made arbors


			HomeShopTech


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## dewbane (Aug 18, 2022)

devils4ever said:


> How's brass and aluminum combo?


It looks like that isn't a great combination. After I did more reading on the topic, I doubt this is ever going to be much of an issue for you no matter what. You probably just aren't going to be exposing it to enough water to create major problems, even if you do use metal combinations that aren't ideal.


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## Larry$ (Aug 18, 2022)

devils4ever said:


> I ordered a set of cutters from China


Please let me know how these turn out. I would like to get a set of 1.25 gear cutters. That seems to be a less available size. Thanks, Larry


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## devils4ever (Aug 18, 2022)

Here's my design so far:


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## WobblyHand (Aug 18, 2022)

Out of curiosity, why the slotted holes?  Also, it seems like a lot of fasteners, for a bottle capper.  Your design is nearly as beefy as an arbor press.  Very cool rack!  Amazing what one can do in FreeCAD.

A FreeCAD question:  Is the model an assembly drawing, or is it just a bunch of bodies in the right places?


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## devils4ever (Aug 18, 2022)

Slotted holes are for wear and/or my lack of precision! Yeah, I probably over built this. That's what I do. 

The FreeCad model was done using A2+ workbench.


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## Alexander McGilton (Aug 18, 2022)

Lot of fasteners indeed. 
Are you able to export a .STEP file of the 3d model? I can show you some ways to reduce fasteners count and posibly weight, while maintain or increase strength. Screws don't like to take shear load in preference to tension and compression in a lesser extent. Add bosses, depressions or tabs to the body to take perpendicular loading.


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## devils4ever (Aug 19, 2022)

I can export a .STEP file for each part, but not the whole assembly.


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## Alexander McGilton (Aug 19, 2022)

That's all good. just something to save me some time modeling off of isometrics. 
Just some examples better explaind in a model than random internet photos. See this taping guide machine, the screws that hold the column to the base go from the under side, vertical into the bottom to the column. Two or four screws going upside down will save a lot of tapping for those L bracts depicted in your modeling.


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## devils4ever (Aug 20, 2022)

I originally had 6 screws attached like in the picture except coming up from the bottom into tapped holes in the upright column, but I changed it thinking the angles were stronger. I can change it back.


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## tq60 (Aug 20, 2022)

Your rack is only supported by the pinion on that side. 

That will cause binding and extra wear and stress.

So make side panels thicker and notch them or add bushing blocks 

Sent from my SM-G781V using Tapatalk


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## devils4ever (Aug 21, 2022)

I see what you've saying, but that would prevent me from adjusting it unless I fix the rack and allow adjustments on the pinion.


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## dewbane (Aug 21, 2022)

devils4ever said:


> I see what you've saying, but that would prevent me from adjusting it unless I fix the rack and allow adjustments on the pinion.


I was thinking about putting a through slot in the capping ram. Have it ride up and down on a pair of internal guide rollers. The rollers would be adjustable, and they would keep the thing positioned securely while it's going up and down. I'm not sure if this would work well or not. I'm just spitballing.


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## devils4ever (Aug 21, 2022)

dewbane said:


> I was thinking about putting a through slot in the capping ram. Have it ride up and down on a pair of internal guide rollers. The rollers would be adjustable, and they would keep the thing positioned securely while it's going up and down. I'm not sure if this would work well or not. I'm just spitballing.



Yeah, that would work. I was thinking of putting a pair of adjustable blocks on the teeth side of the rack above and below the pinion. This might be overkill since it's a bottle capper and not an arbor press?


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## devils4ever (Aug 21, 2022)

So, the set of gear cutters I ordered are M1.25, PA20 Bore 22 mm. I'm looking for a R8 arbor for this. I've contacted a few eBay sellers asking about their products and can't get a decent answer. Search on eBay: "USA 22mm R8 Shank Milling Arbor Gear Mill Cutter Holder Toolholding 7/16-20" for what I'm thinking.

I'm assuming this will work?

I asked if the arbor was keyed and didn't get a response. Can anyone help here?


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## WobblyHand (Aug 21, 2022)

Don't know, but could be a language issue.  Try asking if they have a slot or key to keep the cutter from moving.  Unless you are doing heavy cuts not sure if the key is necessary.  Kind of like the infamous R8 key...

That being said, I'd look for one with a keyway.  Keep us posted, I need to get a 22mm arbor for gear cutting as well.  The ones that I see are pretty large and have a huge left hand nut and extension below the cutter.


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## dewbane (Aug 21, 2022)

It looks like these Chinese arbors are pretty much the same everywhere. I couldn't find a picture of one taken apart, so I went out in the rain for you. You're welcome.This is a Chinese 22mm from Amazon. It says "22mm R8." I put my caliper on the key, and it was about 0.235".




As to the other thing we were talking about, I have this feeling that any kind of bushing or bearing that rides along the teeth on the rack will not fare too well. I started thinking about how you could make a roller bearing to ride on a toothed surface, and I started to think about a pair of idler pinions. It would be a kind of wacky design, but they would roll along the teeth no problem. Shrug.


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## Larry$ (Aug 21, 2022)

I've got one of those arbors like the picture MM posted but for slitting saws. Some of my blades don't have keyways, so I pulled the key out. Those arbors aren't much good for slitting saws. Way too much bulk below the saw but probably work fine fore a gear cutter.


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## devils4ever (Aug 22, 2022)

I just ordered from Amazon "*NEW 22mm R8 Shank Milling Machine Arbor Fit for Milling Machine Bridgeport*". 

It's strange that none of the pictures I could find show the arbor with the nut off like *dewbane *has shown.

Here's my email contact with an eBay seller:
*Me*:
Can you confirm that this will hold a gear cutter with a 22 mm bore? Also, does this arbor have a keyway?

*Them*:
It could not hold a gear cutter with a 22mm bore.
It could hold 20mm one.
And it has a keyway.

Am I missing something here? I'm getting so many mixed messages on this. Both eBayer I contacted said it will not fit. I think they are misinterpreting my question. I think they are referring to the thickness of the cutter?

Anyways, I'm hoping this Amazon arbor will work with the gear cutter set I ordered from China.


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## WobblyHand (Aug 22, 2022)

It should fit your cutters.  A 22mm shank will hold 22mm gear cutters.  If you look at these listings they say dimensions are within a cm!  This means that they don't know what they are selling.  Ie, they certainly are not machinery savvy.  Anyways, I ordered a similar one from AliExpress and will find out in a couple of weeks.


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## devils4ever (Aug 22, 2022)

Ok. Thanks, WobblyHand.

So, I've been thinking of tq60's post about supporting the pinion side of the rack and I think he is 100% correct. I looked at my arbor press and the rack is supported on all 4 sides. I also watched mrpete222's video on a rack and pinion build (nutcracker) and he did the same.

I am adding an adjustable block on the inside to support the rack on the pinion side. This will allow me to move it slightly as things wear or if I miscalculate the dimensions. Assembly drawing update to follow....


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## devils4ever (Aug 22, 2022)

Here's an update to the assembly. I added a U block that encompasses the pinion and allows adjustment. Hopefully, this is enough to support the rack on the pinion side.


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## dewbane (Aug 23, 2022)

It looks plausible. I'm not sure about aluminum on aluminum violence, and who will be the victim. If the rack gets chewed up over time, that's a comparatively hard part to make. If the U-block gets chewed up over time, you can just tweak the adjustment. Seems to me the way to pick which thing is going to wear first is to put some kind of bearing material on the parts of the U-block that contact the rack. Some kind of high density plastic, perhaps. Or back to my other idea, a couple of idler pinions that roll with the rack and just freewheel.

You could always skip al that and just keep it in mind if you have to remake parts down the road. I'm not an engineer, and I tend to massively over-build things.

I envy your skill at making stuff with CAD. I've tried to get my head around FreeCAD and Fusion 360 over the last couple of days, and I am still working from unwritten plans contained only in my head, or maybe the odd crude pencil drawing, because I only have so much free time, and I am not within the same galaxy as actually producing usable renderings with either program. I tip my hat to you.


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## devils4ever (Aug 23, 2022)

dewbane said:


> It looks plausible. I'm not sure about aluminum on aluminum violence, and who will be the victim. If the rack gets chewed up over time, that's a comparatively hard part to make. If the U-block gets chewed up over time, you can just tweak the adjustment. Seems to me the way to pick which thing is going to wear first is to put some kind of bearing material on the parts of the U-block that contact the rack. Some kind of high density plastic, perhaps. Or back to my other idea, a couple of idler pinions that roll with the rack and just freewheel.
> 
> You could always skip al that and just keep it in mind if you have to remake parts down the road. I'm not an engineer, and I tend to massively over-build things.
> 
> I envy your skill at making stuff with CAD. I've tried to get my head around FreeCAD and Fusion 360 over the last couple of days, and I am still working from unwritten plans contained only in my head, or maybe the odd crude pencil drawing, because I only have so much free time, and I am not within the same galaxy as actually producing usable renderings with either program. I tip my hat to you.



Yes. I see your point, but my arbor press is steel (or iron) on steel (same materials for both rack and guide). So, I'm doing a similar idea except softer materials. And this is only pressing on bottle caps. It's not an arbor press expected to exert tons of force.

I've never seen idler gears used to support anything, but it could work. Usually gears are set apart a calculated distance with some small clearance. Idler gears wouldn't have that luxury. Don't know if that would work.

It took me a long time to get decent at FreeCad. I started with F360 and quickly realized the free version would be not here forever and switched to FreeCad. The learning curve is steep on either one. FreeCad has its issues like all CAD software. The biggest one being the topological naming issue, but F360 had its issues too. Just keep using it and using it and it will get easier and easier. I still need to lookup how to do things every once in a while. Since it's free forever, you'll never had to worry about licensing. Use it for personal or commercial use. No problem. Sorry for the long response. I'm a big proponent of FreeCad. Each release gets better and better. I had an issue with the A2+ workbench and posted it on the FreeCad forum. The developer responded and fixed the issue!


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## Moe (Aug 23, 2022)

Hi; cutting your own gear. Is a good project even if buying them is cheaper. Look around and see what is available in your area sometime at scrapyard there some old equipment that there would be a rack you can use. The rack are not expensive to buy . I would use around a 16 DP size it seem this would work good for your project. As soon you have the rack then you can plan on building the gear.


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## devils4ever (Sep 5, 2022)

I have some of the tooling now. I have the R8 - 22 mm arbor and the gear cutters from China have arrived. They look decent and the set is complete with no missing or duplicate cutters. I'll be using them shortly and report how they cut. I also have the 20 degree end mills to cut the rack.

I have materials on order and I ordered the Shars No 00 keyway cutting broaching set. I'm looking forward to getting started.


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## dewbane (Sep 6, 2022)




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## devils4ever (Sep 6, 2022)

Can someone check my numbers?!? I'm doing some test cuts and the teeth look way too pointy/sharp at the top.

Given:
N = 16
M = 1.25
PA = 20

Computed:
OD = (N+2) * M = (16+2) * 1.25 = 22.5mm = 0.886"
Whole depth = 2.25 * M = 2.8125mm = 0.111"


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## devils4ever (Sep 6, 2022)




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## WobblyHand (Sep 6, 2022)

devils4ever said:


> Can someone check my numbers?!? I'm doing some test cuts and the teeth look way too pointy/sharp at the top.
> 
> Given:
> N = 16
> ...


Your numbers seem to be to the standard formulas, but I agree, the teeth look sharp.  Then again, you only have 16T.  The smallest gear I could find was a 20T and 21T M1 gear and they definitely have flats on the teeth tops.  I'm guessing you are going too far in.  Another thing to check is the tooth height.  Is it 0.111" measured?  It you went in too deep the sharp tips would form.

Ruling out any operator error for the sake of argument, are you sure these are Module 1.25 cutters?  Is there something you can check on the cutter profile to be sure?  Just because they are marked M1.25 doesn't mean they are...  Or some craziness with the 1-8 cutters being mis-marked or backwards?  US customary numbers are backwards compared to the Chinese ones...  My cutters do have a number (of teeth) range marked on the cutters, yours do too?


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## WobblyHand (Sep 6, 2022)

I took my numbers from: http://www.metrication.com/engineering/gears.html FWIW.


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## devils4ever (Sep 6, 2022)

Yeah, I'm not sure how to measure tooth height. Suggestions?

The cutters are marked M1.25, but who knows! The cutter I'm using is marked #2 14-16. The only other gears I have are from my mini-lathe which are M1.0, I believe. The depth on these is really small compared to what I cut.

I touched off on the side of the gear blank with the cutter and moved the Y-axis in 0.111".


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## WobblyHand (Sep 6, 2022)

devils4ever said:


> Yeah, I'm not sure how to measure tooth height. Suggestions?


Honestly don't know.  It's like one needs a very small pin or very thin depth gauge.  There's probably some smart person that has figured out how to use a round pin of the right size that just lies on the teeth and know the important details from that...  Kind of like measuring dovetails.  Maybe you could doodle in CAD with something like that?  

When things get back to normal here, I can think about it some more.  Have to take my kids and grandson to the airport soon, so it's going to get crazy here in a few minutes!


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## devils4ever (Sep 6, 2022)

I found this website to use pins for measurement.

Using 0.125" pins (3.175mm), the distance over the pins is 1.023". I measure about 1.001" - 1.002". Somethings off!!!


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## WobblyHand (Sep 6, 2022)

devils4ever said:


> I found this website to use pins for measurement.
> 
> Using 0.125" pins (3.175mm), the distance over the pins is 1.023". I measure about 1.001" - 1.002". Somethings off!!!


Your link also has a calculator for blank diameter and comes up with 0.8858, same as what you have.  Can you measure the root diameter, should be 0.6644" for a correctly made gear.


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## devils4ever (Sep 6, 2022)

The best I can measure, the root diameter is about 0.654".


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## dewbane (Sep 7, 2022)

It does look like something is a little off, but you didn't go far enough to answer the most important question. The final tooth is the most critical part of cutting gears. If it's skinny or fat, you screwed up. One of my first gears looked like an escape wheel.

Here.



On the top one, I didn't set the Z axis correctly. I got a gear-like object, but the teeth were off by half of the width of the cutter.
On the bottom one, I made a dividing head cranking error that resulted in a skinny tooth, and ultimately a fat tooth.

Until you go all the way around, it's hard to say what went wrong where. Your teeth to this point look good. A little pointy. Maybe you're cutting in too far. But the real question is will the gear work? The first gears made by humans were hand filed and kind of crappy, but they functioned.

It takes Mother Nature and/or God to make perfect gears, such as those on the planthopper (Photo courtesy of LiveScience):


I say just run with it, make your gear, pointy teeth and all, and see if it runs. It will probably run as long as all the teeth are even. You can obsess yourself right into oblivion in this hobby if you let yourself.


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## devils4ever (Sep 7, 2022)

I never finished cutting the gear when things looked awry. I went around more than half way so I could measure the root diameter and the distance over wires.

So, looking at this more closely:

root diameter = OD - 2*(whole depth) = 22.5mm - 2*(2.8125mm) = 16.875mm
or
root diameter = OD - 2*(whole depth) = 0.866" - 2*(0.111") = 0.644"

Since I measured the root diameter as 0.654", I must have went in too far. How? I don't know. I carefully touched off on the side of the gear blank with the gear cutter running. I just kissed it. Then, I used my mill to move in 0.111". 

_Unless my mandrel flexed and the gear blank got pulled into the cutter?_ I made the 8" long mandrel out of 12L14 steel with 5/8" diameter at one end (into dividing head chuck) and threaded 3/8" on the other to hold the gear blank.

I may try again today and just cut on opposite sides of the gear blank (for quick measurement) and keep taking cuts until the root diameter and distance over wire is right.

This is quite the mystery.


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## devils4ever (Sep 7, 2022)

Here's my setup:


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## Ischgl99 (Sep 7, 2022)

devils4ever said:


> I found this website to use pins for measurement.
> 
> Using 0.125" pins (3.175mm), the distance over the pins is 1.023". I measure about 1.001" - 1.002". Somethings off!!!


For a 20 degree pressure angle, your measurement over 1/8” pins should be 1.015, I think you put a 14.5 degree pressure angle in the calculator to get 1.023”.

That last picture is much better then what the first one looked like.  That looks like the proper form, just maybe a little too deep.  If you go too deep, the tip will get thinner, so that might be your issue.  Maybe try another gear and go in steps instead of full depth the first pass and see if you get something that measures right.


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## devils4ever (Sep 7, 2022)

Ischgl99 said:


> For a 20 degree pressure angle, your measurement over 1/8” pins should be 1.015, I think you put a 14.5 degree pressure angle in the calculator to get 1.023”.



I get 1.0235" for N=16, module=1.25, PA=20, pin diameter=3.175mm (0.125"). See below.

Inputs
Number of Teeth:    16
Gear Type:    External
Module:    1.25
Pressure Angle:    20    degrees
Pin Diameter:    3.1750    mm
Profile Shift Coefficient:    0

Outputs
Measurement over Pins:    25.9970    mm    1.0235    in
Minimum Pin Size:    2.0222    mm    0.0796    in
Pin Size on Pitch Line:    2.1742    mm    0.0856    in
Maximum Pin Size:    4.5094    mm    0.1775    in
Pitch Diameter:    20.0000    mm    0.7874    in
Profile Shift:    0.0000    mm    0.0000    in


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## dewbane (Sep 7, 2022)

That looks a lot like a Grizzly g0704.

I have no idea if it's actually contributing to your problems, but after reading through a bunch of clock making books, I totally changed my goals for my own setup. The 3-jaw "you get a center, but maybe not the center you want" scroll chuck is gone, replaced by a MT2 ER32 collet chuck in the dividing head. I'm no longer using the tailstock at all. I haven't actually fabricated it yet, but I'm going to copy a blank holder from the "Huckabee wheel making fixture" from "Building an American Clock Movement" by Steven G. Conover, and size the the shank to fit one of my ER32 collets. Call it 0.750".



What did Mr. Huckabee get right that I did wrong? He realized the threaded connections are the enemy of concentricity. The gear blank in this diagram registers on the 0.326" diameter that sticks out of the chuck/collet. The blanks clamp through the #10-32 threads, with the aid of the washer. Varying widths of blanks, and/or stiffening plates are accommodated, and everything will turn out concentric, because the threads aren't relevant to the concentricity of anything.

This is hugely different from the gear cutting arbor I made, which put the threads and the registration diameter on a rod that screwed into the left portion. Left and right rods were the same tool steel blank, the hole was reamed, but with this nonsense clamped between the 3-jaw scroll chuck on my dividing head and a tailstock, my parts basically stood no chance of coming out totally concentric.

When I redo this setup in the near future, I'm going to make a fixture that clamps into the ER32 on my dividing head, and has no tailstock support at all. This should be totally fine for 0.0625" clock wheel blanks, although you should probably devise a setup that involves tailstock support, because your pinion is relatively long.

My fail arbor:


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## WobblyHand (Sep 7, 2022)

Ischgl99 said:


> For a 20 degree pressure angle, your measurement over 1/8” pins should be 1.015, I think you put a 14.5 degree pressure angle in the calculator to get 1.023”.
> 
> That last picture is much better then what the first one looked like.  That looks like the proper form, just maybe a little too deep.  If you go too deep, the tip will get thinner, so that might be your issue.  Maybe try another gear and go in steps instead of full depth the first pass and see if you get something that measures right.


Could be the website calculator.  I got the same numbers as @devils4ever .

The cut off gear looks a lot better than the earlier picture.  I think the teeth were cut a little deep.  The root circle is 0.01" too small.  Since the cutter widens near the base a tiny displacement in depth will make a large change in tip width.  Try again.  Do go all the way around, because that's what counts.


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## Ischgl99 (Sep 7, 2022)

devils4ever said:


> I get 1.0235" for N=16, module=1.25, PA=20, pin diameter=3.175mm (0.125"). See below.
> 
> Inputs
> Number of Teeth:    16
> ...


Looks like I made a typo when converting the 1/8” to metric and was off by 0.075 on the pin diameter when I did it, but interesting enough, switching to 14.5 degree angle in the calculator gave almost exactly the correct number.


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## devils4ever (Sep 7, 2022)

My arbor/mandrel (which is correct?) has a solid section where the gear blank sits. I turned the solid section to 0.374" and reamed the gear blank bore to 0.375" so there's is very little play.

I agree about the chuck, but I don't have a collet chuck for the dividing head like I do for my lathe. Maybe, this will be my next purchase!


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## Ischgl99 (Sep 7, 2022)

Unless your chuck is really out, I don’t see that affecting things enough to give you the results you did.  Have you put an indicator on the mandrel/arbor to see how much runout you have when turning the chuck?  Another possibility is your center hole on the end of the arbor might not be centered enough, or the arbor is bent, and it might be enough to cause one side to cut deeper then the other and give you the results you are seeing.

By the way, as a Devils fan, I approve of your forum name


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## devils4ever (Sep 7, 2022)

I measure less than 0.0005" runout on the mandrel itself and about 0.004" on the gear blank. I'm surprised the gear blank has that much runout. Next time I'll use a boring bar instead of a reamer.

Long time Devils fan!


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## devils4ever (Sep 7, 2022)

Some more updates. I decided to creep into the gear blank slowly and measure the distance over wires using 0.085" and 0.086" gage pins. This size gage pin should put me on the pitch circle. I averaged the two distance since I didn't have two the same size. The 0.086" pin should be 0.9075" and the 0.085" pin should give 0.9042" and average to 0.9058".

So, I started at 0.050" depth of cut and saw it was way too shallow.

I progressed as:
Depth     Distance
of cut    over wires
-------   ----------
0.065"    0.985"
0.075"    0.964"
0.080"    0.954"
0.085"    0.943"
0.090"    0.936"
0.095"    0.921"

I stopped here since the tops of the teeth look "about right" to me. See below. Theoretically, I should have about another 0.015" to go over the wires and another 0.016" depth of cut. 

What do you think? I can take some more off if needed before I remove this from the mandrel.


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## Ischgl99 (Sep 7, 2022)

I grew up not too far from you in Branchburg and have been a Devils fan for a long time, but I seem to jinx them and they lose when I watch, so my son tells me I should watch the Rangers games instead.

I’m not a gear expert by any stretch of the imagination, but that looks pretty close to what I would expect, but needs a bit more.  I have an M1.25 30T gear on hand, using a magnifying glass, I measured the flat at the top of the tooth to be about 1mm.  Measuring the root diameter, I get a tooth depth of 0.111”, so I think if you can get better runout from your blank, you will be good to go.


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## devils4ever (Sep 8, 2022)

Well, I decided to cut a little deeper and went to 0.101" depth of cut which gave a distance over the pins of 0.912". This is short by about 0.003" per side, but I think the teeth look about right. The tops of the teeth measure less than 1 mm.


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## Ischgl99 (Sep 8, 2022)

That looks pretty good, but the proof would be to cut that in half and mount on pins at the required center distance and see if they mesh properly.


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## devils4ever (Sep 8, 2022)

Remember this is meshing with a rack, not another gear which I made purposely made adjustable.


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## devils4ever (Sep 11, 2022)

I finished the rack and I'm _very pleased _with the results.

I used a 3/16" (~4.76mm) 20* end mill for the bulk of material removal and a 1/8" (~3.17mm) 20* end mill to get to final depth. Since these end mills are so small, I took 3 passes with each. Each pass took over 30 minute on my CMC mill so cutting this took the better part of my morning! 

I was cutting at 3 IPM since my mill's top RPM is 2500 and I didn't want to snap these tiny cutters. According to Little Machine Shop's "Speeds & Feeds" webpage, I should have be using 27,500 RPMs for the 1/8" end mill and running it at 55 IPM!


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## devils4ever (Sep 12, 2022)

I decided to add Oilite bearings for the main shaft since it's steel and the side plates are Aluminum. I ordered a few from MC.

I've never used them before. Are they just pressed in? What kind of tolerances are needed? Can they be easily cut to length? How? Saw? Mill? They seem very porous.


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## devils4ever (Oct 19, 2022)

My project is done. I posted it here. See post #7673.

Thanks for everyone's help!


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