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DeadSkunk  (Warren)
DeadSkunk (Warren) UltimaDork
4/4/21 8:32 a.m.

No need for a lathe.........cheap Chinese drill press.........

kevinatfms
kevinatfms GRM+ Memberand Reader
4/6/21 6:15 a.m.

Would anyone want to make a set of bushings for a GRM friend?

DeadSkunk (Warren) said:

No need for a lathe.........cheap Chinese drill press.........

Yes!!! I saw this in a fever dream once, and I was pretty sure I had to try it.   Your version looks at least 40% less likely to draw blood than the one in my head though, so I’m probably going to steal this idea.  Thanks!

 

stafford1500
stafford1500 GRM+ Memberand Dork
4/6/21 7:06 a.m.

In reply to kevinatfms :

Send me some dimensions and quantities, and i will send back quote. Pictures or drawings would be extra good

dean1484
dean1484 GRM+ Memberand MegaDork
4/6/21 7:22 a.m.

I jammed together a home built lath and what I discovered is that many drills are built to a quality that you can not use them. They have way to much run out in the bushings/bearings. I finally ended up with a Comercial grade Milwaukee 1/2 inch drill that was good enough.  I also needed a drill at the time.  

kevinatfms
kevinatfms GRM+ Memberand Reader
4/6/21 7:36 a.m.
stafford1500 said:

In reply to kevinatfms :

Send me some dimensions and quantities, and i will send back quote. Pictures or drawings would be extra good

Replied to your email. Thank you for reaching out. Quite excited.

DeadSkunk  (Warren)
DeadSkunk (Warren) UltimaDork
4/6/21 8:02 a.m.

In reply to dean1484 :

Oh, mine has lots of run out, but I just went very slowly and it's for a Challenge car, so "good enough".

CAinCA
CAinCA GRM+ Memberand Reader
4/6/21 12:47 p.m.
Driven5 said:
OnTheChip said:

Does the control arm motion occur between the bolt and sleeve, the sleeve and bushing, or busing and arm?

Typically the sleeve rotates in the bushing and the bolt is just there to clamp it all together, but that's just the beginning.  In order for everything to locate, support, and move properly, you'll also need to figure out the fit between the bushing OD and the control arm housing ID, the amount of resulting shrinkage of the installed bushing ID, the fit between the sleeve and installed bushing ID, the fit between the bushing flanges and the mounting bracket, and the fit between the sleeve and the mounting bracket to ensure the fit between the bushing flanges and the mounting bracket when the bolt locks the bracket down tight against the sleeve. And that's all assuming that the suspension you're working with has already been confirmed as operating only pure single axis rotational motion for each bushing being replaced.

For all of the 'technical' articles/blogs/posts I have seen out there proclaiming how 'easy' it is to make (or have made) DIY bushings, I don't think I've ever seen one that includes any of the 'minor details' that are actually critical to doing so correctly. It always seems to be some variation on...

Phase 1: Collect Delrin

Phase 2: ?

Phase 3: Bushings

THIS ^

You really need to nail the fits in order for the bushings to work correctly. The OD needs to be a light press fit. The ID needs to be a slip fit. A few thousandths too big or small and they won't fit or they will rattle and wear early. 

I have a stick of Delrin I bought to make rear swing arm bushings for my brother's 356 kit car. I haven't made them because I really want the arms and sleeves in my hands before I start turning. Second hand measurements and TLAR engineering won't cut it IMHO.

WillG80
WillG80 GRM+ Memberand Reader
4/6/21 2:39 p.m.

Does anybody know if the $500 wood lathes are beefy enough to turn plastic and aluminum? 

84FSP
84FSP UltraDork
4/7/21 8:38 a.m.
Randy_Forbes said:

Fun projects!  I made a couple of forays into bushing making__machined and molded__some years back with good results.

Before Jeff Ireland/Ireland Engineering started marketing his urethane subframe mounting bushings for the E-30 esque Z3 and M Rdstr applications, I was molding some "bushing stuffers" from a pourable Devcon 2-part urethane (Shore hardness unknown, as I've slept since then...).  These filled the longitudinal voids in the OE bushings and also packed the space at the tops and bottoms to eliminate a substantial amount of the excessive compliance.  By all accounts, they were a success.  The professionally manufactured and store-bought polyurethane bushes from IE were a substantial improvement on what I was making, so I abandoned them and have probably purchased and installed Jeff's bushes in 150-175 cars since then.  I wish I could remember what album has the pictures of my molds (made in 2-pieces from a pourable aluminum/resin product from Loctite).  I'll edit this post if I come across them, but I too used a plastic food-container dish to make the molds!

The machined bushes were turned in both UHMW (Ultra High Molecular Weight bushing material) and a bronze alloy.  I never finished the bronze ones to size, opting to install the UHMW ones for a test first.  They are still in the upper/outer pivot position, allowing a decrease from +1* (positive) camber to approximately -2* negative camber on my '57 Healey.  I made them eccentric, so that they were adjustable to enable matching both sides.  Given that the UHMW bushes have been in for nearly 15 years already (recently inspected during a front shock upgrade) and found that there's still no perceptible wear at the ends or bolt-holes and that the bronze bushes only need (both of) the ends trimmed to size, I doubt I'll need to make any more for this application in my lifetime!

 UHMW bushes before ends were trimmed to size

Fitted to the Healey's upper trunion (previously machined for straight bore; original 1/2-bushes were tapered)

So yes, Doable AND Fun project that anyone can do at home**
 

 

 

** NO Dads were used or otherwise harmed during the above exercises. 

UHMWPE has fantastic wear properties despite not having the highest temperature range.  They should last a life time if properly avoiding shock hits at higher temps.  Delrin/POM is also good but can't hold a candle to the wear and density of the EHMWPE despite holding better high temps.

asphalt_gundam
asphalt_gundam Reader
4/7/21 2:55 p.m.

I'll be giving Recycled PTFE a try for motor and trans mounts soon. Picked it because of the up to 500 degree temp range due to header proximity and the Durometer being a little stiffer than rubber.  I'm hoping they'll keep reasonable movement for the engine and transmission but last all year without tearing like the stock mounts. More room by ditching the bulky stock mount will be a plus too. 

Tom Suddard
Tom Suddard GRM+ Memberand Director of Marketing & Digital Assets
4/7/21 3:06 p.m.

In reply to WillG80 :

You're far better off picking up a used metal lathe. Even if you find one that's been abused and has a bunch of runout, it will still work fine for making plastic bushings.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
4/7/21 5:06 p.m.
jerrysarcastic (Forum Supporter) said:
DeadSkunk (Warren) said:

No need for a lathe.........cheap Chinese drill press.........

Yes!!! I saw this in a fever dream once, and I was pretty sure I had to try it.   Your version looks at least 40% less likely to draw blood than the one in my head though, so I’m probably going to steal this idea.  Thanks!

 

I've used this method, with a really coarse file and a 99 cent hockey puck, to make a one piece shift linkage "golf ball" for my A2-chassis VW.

Lasted forever, the VW part would last about six months.

 

(The A2 chassis shift linkage was an ingenious way to transfer motion from the shifter to the top/front of the transmission, without being affected by drivetrain motion.  But soooo much opportunity for play to develop.)

classicJackets (FS)
classicJackets (FS) Dork
9/22/21 5:34 p.m.

For making your own bushings on a challenge budget, is there anything better/cheaper than this?

https://www.amazon.com/gp/aw/d/B07VSHVMVG/ref=cm_cr_othr_mb_bdcrb_top?ie=UTF8#cm_cr_carousel_images_section

I've got 4 to make, not huge, and actual replacement would be $50+, so trying to avoid that.

maschinenbau
maschinenbau GRM+ Memberand UltraDork
9/23/21 9:49 a.m.

In reply to classicJackets (FS) :

I literally just bought that exact kit and plan to use it in the next week or so. I'll report back with my experience.

maschinenbau
maschinenbau GRM+ Memberand UltraDork
9/25/21 7:06 p.m.

First pour. it's going...okay. I mixed 0.5 oz (.25oz of each part) and 1 drip of dye turned it black. Combination of cardboard and hot glue mold. It leaked big time, so I kept pouring the fill until it started to set up. I come back two hours later and it has expanded and looks bubbly. Some reading up tells me I have a moisture or mixing problem. The amount was so small that I didn't use a stirrer, just kinda swished it around the cup a good bit. Stirring and scraping the walls is recommended. Vacuuming the mixture cup is supposed to help too. Either way, not looking good for this pour so I'll probably have to try again. Curr time is 12 hours so I'll check tomorrow and cut into it to see how bad the foaming is.

 

classicJackets (FS)
classicJackets (FS) Dork
9/25/21 8:29 p.m.

In reply to maschinenbau :

Awesome. Looking forward to hearing how it goes!

I ordered some out of fear I'd wait too long and run out of time to figure it out, so I'm hoping for good news from you!

matthewscarpetta
matthewscarpetta
10/3/21 3:30 p.m.

In reply to JG Pasterjak :

The best thing to do with having your own street legal race car is to have machine tools available in your garage. Luckily I'm a machinist and looking into getting a conventional Mill-Turn combo similar to the Smithy Granite.

maschinenbau
maschinenbau GRM+ Memberand UltraDork
10/7/21 7:32 a.m.

Update: I rigged up a quick-n-dirty vacuum chamber using some plexiglass, a tapped hole matching a fitting from my A/C vacuum gauges, a Pyrex food storage container, and some leftover butyl rubber trim. It...worked! I started a stopwatch after mixing, much more thoroughly this time with a plastic spoon. Then I put it in the vacuum chamber and sealed it as quickly as possible. Within 1 minute the mixture over doubled in size from all the bubbles escaping. Removed vacuum and let it calm down for 30 seconds. Began the pour around 4 or 5 minute mark. Came back 2 hours later and it looked much better than last time! No foaming or expansion. After curing overnight it feels very strong and solid. For this part I just used duck tape to seal the cavity, but for the control arms I will 3D print or turn some centering plugs. 

This mixture started just below the line for 1, but under vacuum it expanded beyond the 2 marking. After removing vacuum, it settles back down.

Immediately after pouring vs after overnight cure. Just a handful of small bubbles and no expansion. 

Back side where I peeled the duct tape off. Next I'll try plastic plugs so I can center the inner sleeve better.

 

maschinenbau
maschinenbau GRM+ Memberand UltraDork
10/27/21 12:02 p.m.

Another update: I broke the 1/4" plexiglass so I made a new base out of 1/4" steel. I also drilled and tapped a 1/8" NPT hole. The fitting came directly out of my A/C manifold gauges, on the bottom right, and threaded into the plate. Pyrex seems to be strong enough.

Noddaz
Noddaz GRM+ Memberand UberDork
4/11/22 12:05 p.m.

In reply to maschinenbau :

Nice setup!  And how did this work out?

Scott

maschinenbau
maschinenbau GRM+ Memberand UberDork
7/19/22 10:17 a.m.

I'm going to keep updating this thread - for science.

I wasn't happy with the Amuhzon kit linked above (Enduro Flex brand). It was WAY too soft and flexible to be Shore 80 hardness. Like, I could stick a socket extension through the bushing and flex it easily by hand. No way I was putting that on the car. After leaving a review exposing this, Amazohn has re-listed the product under a slightly different name with my review no longer attached to the product. You get what you pay for, and I no longer pay for Prime...anyway...

I was able to press out the last round of stuff with my bench vise (not a good sign). I bought a kit of Shore 80 RTV Urethane from the same supplier pictured in the original article above. Here we go again...

The Amazon junk was way too flexible. Feels like soft silcone. I can turn those cylinder inside out by hand.

I learned a new trick from a fiberglass guy on youtube - hot glue to seal molds from leaking. The sway bar links I just glued to cardboard. The control arms I 3D printed a plug that centers the inner metal sleeve.

Vacuum chamber is still my trusty pyrex container sealed to a 1/4" plate with butyl rubber rope sealant.

De-gas. This new stuff has a 45 minute pour window, so no need to rush like the last stuff's 7 minute window. This is almost triple the original mixed volume. After removing vacuum, it settles back down to original mixed volume. Pretty neat.

I still got leaks but so far it's looking good. I was able to bunch paper towels over the leaking areas to stop the flow, then re-fill with what was leftover. I will de-mold today or tomorrow, and test the flexibility after a week. The datasheet says full cured properties are reached after 7 days, so I won't flex the rubber til then.

Hope this helps someone in the future

maschinenbau
maschinenbau GRM+ Memberand UberDork
7/20/22 10:14 a.m.

I tried again this time with much more hot glue. I also found it helps to apply the hot glue to the plastic plug, instead of to the metal part, because the metal acts as a heat sink, cooling the hot glue too quickly for you to work. No leakage this time, so the level of the pour didn't recede during cure. Parts look much better in my opinion. 

The sides plugged by the 3D printed parts still have the print texture, but not a big deal to me. You could prevent this by sanding or smoothing the plastic parts with body filler.

I won't do the flex test until this weekend when it's fully cured, which is also when I will reassemble the suspension. 

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