Hudy Mods

[HO RacePro]

I'm not sure if this is the right place to post this topic, but here goes...

At the most recent IHSR event I had a sit-down with the host to discuss issues he has identified with the club's Hudy tire truing machine. There are two of them.

First, and the one he is most concerned about, is how difficult it is to get the sanding drum axle parallel with the wheel/tire axle. This alignment issue arises whenever the sanding drum needs to be replaced or serviced. He has never found a good way to get those two axles back to being parallel after the disassembly/reassembly necessary to access the sanding drum. If those two axles are not almost exactly parallel truing a tire will make it slightly conical instead of cylindrical.

His second concern is he finds the axle that supports the wheel/tire is too short. That is, at least, for the 3/32 inch diameter axle used for 1/32nd scale wheels.

So I have borrowed the club's Hudy machine to investigate how it could be modified to address those two issue. I'm good at such things, pardon my modesty.

But after 40-some years doing engineering in industry I've learned that, should you confront a technical problem, you are almost never the first person to do so. It is always worth your time to check around and see if someone has solved it already. And it is almost always better to buy an existing solution rather than invent one of your own. Or simply hijack an existing solution, file off the serial number, and furtively install it without letting on where it came from.

Was that last a joke? Dear children, I would never do such a thing. Truly!

So, before I delve into some rather wonky design tasks I'll ask, has anybody worked on these issues before? Any solutions out there? Can I buy one, or simply slip it under my coat?

[Mitch58]

I've taken mine apart more than once and it always goes back square, has yours been modified in some way?

As for the axle shaft, take a blank 1/8" axle down to the local machinist and have one end milled to 3mm and the other to whatever you want it to be. I took a spare 5/40 threaded axle and had one end machined to 3mm so I can true tires for the old '60s cars. It works great.

[HO RacePro]

I don't think our Hudy has been modified. I do know that race host is hyper-particular about car prep. Might have something to do with him winning much of the time.

I've not established a working relationship with any machine shops in the area. Maybe it is time I did.

[Kevan]

I made a new axle from a mold tool ejector pin, at one stage it ran the same length as the drum but found bad resonation when grinding two tyres at once so cut it off and do one at a time.

As far as parallel axis, parts really need dowelling at the factory but that's extra cost. Wouldn't it be a whole lot easier and quicker to mount stop blocks on the base plate for the removable mounts to push up to whilst tightening the screws underneath.

[HO RacePro]

Kevan, I like your idea of stop blocks. I assume you don't have any for sale?

My take on that would be to have one contact screw mounted in each stop block to allow adjustment. You could leave one screw adjusted and loosen the other when removing the plate that supports the sanding drum. When you replace the plate all you should need to do is tighten the one screw and things should be aligned. Neat!

I'd be tempted to dose the one screw with penetrating Loctite after initial adjustment. So useful that stuff.

[Kevan]

No stop blocks I'm afraid but Allen bolts screwed into the base plate with the heads uppermost would work.

[RichD]

If the drum supports are aligned properly to start with and you need to replace the drum using stop blocks is the way to go. I have always been concerned that the OD of the 3/32nd axle is undersized. The machine comes with a 1/8th axle that I would never use, so I could have turned that down if I had access to a lathe. I could try to find a shop to do that for me. The Hudy axle is also too short with some wheels. It would be nice to be able to turn the wheels around so that I would be sure that the tires would not have a slight taper. It would not be a good idea to make the axle so long that you could do two tires at once.

[HO RacePro]

Rich, I thought you had a benchtop lathe. But if you don't I know Gerry does.

Problem is, hardened axles are, well, hard. Too hard to cut with a lathe. Grinding would be the right way to cut down an axle. Maybe Peter has the equipment.

A stepped shaft might be a good job for emachineshop.com. 'Specially if I'd want to get a number of them for sale. Should be easy to sketch and get a quote.

Is Hudy still in business, making machines? If so, it might be worth talking to them to see if they'd make the replacement part.

All that said, I will be trying to make a longer stepped axle using a 3/32" drill blank with a 3mm sleeve. Said sleeve cut from hard precision stainless tubing that I'm hoping will be a close fit to the axle. I'm prepared to ream the ID of the tubing to size if it is too tight a fit. I'd like to hope the assembly will be concentric. Best I'll be able to do with my own tools. Anyway, worth a try.

I'm waiting on a delivery from McMaster-Carr for the required goodies. Still puzzling out how to design the stop blocks. Clearances are an issue.

My original idea was to 3D print the alignment parts. Now I'm thinking I'll use my benchtop mill to make them out of aluminum. Maybe even steel. To do it right i may need to install them using dowels.

Ed Bianchi

[gsnopoint]

Ed, if you find someone local to fabricate a longer axle for 1/32, please let me know. I asked this same question a few months back. I haven’t found any place near me that can do it.

[Pappy]

http://slotblog.net/topic/68026-adjusting-the-hudy-tire-truer/

[HO RacePro]

Thanks a ton Pappy! That video is worth gold!

Admin guy, we need to make this video sticky and easy to find. Do we need a separate forum for tools? (Say yes!)

This has given me new ideas for adding adjustment features to IHSR's Hudy. Should be simpler and more comprehensive.

Now didn't I tell you it is worth checking into whether other folks have solved your problem before you invent your own fix?

[Pappy]

Ed,

Go on Slotblog and type in Hudy Tire Truer in the search box at the top of the page and you'll get all kinds of threads on Hudy's.

[Kevan]

Using a temporary stop block to do the job

[nulife]

I have a Hudy, my second one. I quit the hobby once....and came back. Had a hard time finding a Hudy this second time around. On my first Hudy, I had turned an aluminum rod to 1" and drilled it to fit the Hudy axle shaft. I would put that rod on the Hudy axle and press it against the drum and then tighten the pillow block screws. Best I could figure out...... seemed to work. Is there ever a case where slot racers want a tire to be sanded in a taper? Anyways, the Hudy parts seem to be precisely machined, it doesn't make sense that the center pillow block is in a slot rather than a concentric hole. This time I'm thinking of replacing the two .1165 (2.96mm) rods that are used for the pivot and replace with one 2.75" long 3mm rod. That would make a continuous straight connection between the two end blocks. I will let you know how this works.

[RichD]

The Hudy tire truer is still listed on their site, but none of the US suppliers that I checked has them in stock. Pendle may have them. There is a machine by Slotcars.it Technology that should keep the tire square with the sanding drum and will do two tires at once. The hitch with that machine is that it looks like the axle has to be removed to mount the tires/wheels. In any case the company website lists it as being out of stock.

[HO RacePro]

It looks like there are adjustments for squareness between the sanding drum and the tires on the machine pictured above. If so, a superior design.

I am working on adding adjustable stop blocks on the IHSR Hudy. And I have the parts now to make a longer axle for the tire. Test-fitting same they look like they'll work. Once assembled I'll check concentricity and straightness with my dial indicator. Stay tuned.

[Pappy]

The first thing I think about when doing two tires at the same time is doing two silicone tires at the same time. One silicone tire will bog down the motor if you feed in more than a couple of thousands of an inch at a time. I like the concept of this design but wouldn't try two silicone tires at the same time. Plus we don't really know how accurate the feed is. There was a company about 15 years ago that made a tire truer that would do two tires at the same time but was a total piece of crap and I returned it as many others did. I'm not saying this is not a really good tire truer, just saying I'd like to know more about it before I'd buy one.

[Kevan]

I think this has been out of production for years.

[HO RacePro]

Nulife, I once experimented with tapered tires when I was racing 1/32nd sprint cars on an oval track. The idea was to help the car turn into the corners and possibly make it around faster. I also canted the front axle to simulate steering into the corner. I even sanded down the diameter of the left front tire to simulate differential and help the steering, because the car had a solid front axle.

Both rear tires had a conical shape, and the left tire was smaller overall than the right. Both tires had full contact with the track across their width. The result was, without a motor in the car, if pushed it would go in a circle instead of straight. I tried to set it up so the size of the circle approximated the radius of the track corners.

The result, the car did corner faster, but by crabbing down the straights lost as much as I gained. I could go into the corners faster, and through and out faster, but my speeds down the straights was not good enough. I could run mid-field but not at the front.

There was a lot of setup I could have played with, and possibly gotten a better result. More or less taper, front axle setup, different gearing. There might still be an advantage to tapering the rear tires. But I'm not racing sprints anymore, so somebody else will have to take the lead on this.

[Michael Squier]

And that’s exactly the same problem my full scale racers have, set it up for turning or straights. It’s always a compromise and each track needs a different set up. They shave full sized tires and some taper the fronts for simulated camber if they can’t adjust it in the suspension. It’s amazing how many similarities there are between scale and full sized racing.

[HO RacePro]

Michael, I suspect one of the biggest similarities between scale and full-size racing is there is never enough time or money!

[RichD]

Doing two silicone tires at once could be a problem. If you grind the tires with too much pressure they will probably never get trued. The idea is to remove the high spots, if you use too much pressure you will compress the tire, the tire diameter will be reduced, but the high spots will not be removed. I power my Hudy with a Pyramid supply and the motor pulls 1 amp when I am not grinding. I increase the pressure until the meter reads 1.5 amps when I am grinding. Truing silicone tires will quickly clog up the sanding drum. After about 30 seconds you would need to stop and clean off the drum with a gum rubber block that is sold for that purpose. If you keep on grinding after the drum is clogged the tire will just get very hot and if you have used Superglue that will debond. You can greatly increase your grinding times if you squirt soapy water on the drum while you are truing.
The procedure that I use is included in this article: https://drive.google.com/file/d/1qBi...ew?usp=sharing

[nulife]

I did order a 3mm 2.75" long hardened steel rod from McMaster Carr. I replaced the two shafts that come with the Hudy with this one rod. The original rods are 2.96mm and the 3mm was too tight....so I used my dremel to polish the rod 600 sandpaper and Novus and then finished with semichrome buffing. I also used a detail Qtip in the dremel to clean/polish the holes in the mounting arms. I loosened the center mount put the shaft through and then tightened the center mount. On the best I can exam it....it seems to insure that the axle holder is parallel to the sanding drum.