4x100 Redrill Template

[sketchman]

If something like this is already on here, forgive me. I didn't find it.

So, you want 4x100 in the rear and can't find an Aspire swap, can't afford one, or just don't want to swap the rear for whatever reason. And you don't want to or don't have the option to get a machinist to change the pattern on the stock drums.

No problem. I will be doing this job myself in the near future so I worked up a template to do it backyard style. No measuring, no lining up the pattern by the bearing race to get it centered, etc. Print it out, cut out the 114.3mm spaced bolt holes and center bore, and slap it on the drum for instantly lined up 100mm spaced holes.

The new holes are centered directly at the ends of the curved lines without the black circles on them. The ones with the black circles are 114.3mm apart and there to line the whole thing up. The center bore is to the correct 59.6mm size too, so it should make this job very easy.

As a side note, if you're doing threaded studs instead of knurled ones that pull through, you need a 10.5mm drill bit and a 12x1.5 tap. I'd also recommend a punch to get a good solid centered dimple for drilling the new holes.

IMPORTANT: You MUST print it out at 300dpi. If you don't the whole thing will be off.

[Larry Hampton]

I tried doing a tail light template and never could get it to print the correct scale.

[moz]

Needs to be in DWG format to guarantee scale.

[sketchman]

I've done other things like this before. If you print it at 300dpi it will be right.

I did a cluster overlay that worked perfectly using this same method. If it doesn't work you're doing something wrong, or something is wrong with your printer. I use an app called Irfanview to print with complete control. It's free and gives you the option to print size by dpi. It's well worth having around.

If anybody tries it and has trouble, let me know. I can print them off and send them out for $1 plus a stamp. No worries.

[sketchman]

I'm getting ready to drill some new drums, so I printed this out and snapped a couple pics to show it really will work. It's spot on to the finest detail, as far as a cheapo mic can measure anyway.

[SiliconSoul]

Thanks for this Sketchman! I may make use of this down the road.

[sketchman]

Sure thing.

[Advancedynamix]

Stock drums are not good for drilling because of the ribs and reliefs in them. However, some aftermarket replacement drums will work. I have had luck with ac delco powerstop brand rear drums.
Also, iirc Greg tried drilling drums backyard style and he wasnt happy with the results. He is very talented with backyard mods, so chances are the difficulty level of this is very high. Not trying to discourage here, just offering a disclaimer. Hub bolt patterns need to be held to a high tolerance, otherwise you'll have safety issues.

[moz]

I wonder if DW rear hubs would bolt on to the DA arms.
DW 121 has 4x100 stud pattern
And they're nice and small like the DA item

[sketchman]

Stock drums are not good for drilling because of the ribs and reliefs in them. However, some aftermarket replacement drums will work. I have had luck with ac delco powerstop brand rear drums.
Also, iirc Greg tried drilling drums backyard style and he wasnt happy with the results. He is very talented with backyard mods, so chances are the difficulty level of this is very high. Not trying to discourage here, just offering a disclaimer. Hub bolt patterns need to be held to a high tolerance, otherwise you'll have safety issues.

Duly noted. Wasn't aware that anyone had tried this before.

I'll be the lab rat for this method. So far I've got a another tip. Use card stock to print it if you can. But even with regular printer paper it's going well so far.

Top down.


And posed to show the center bore works too.


You want to keep as much of the paper sheet in tact as possible while you're doing this(don't cut closely against the printed lines). The more paper there is to support the printed pattern the more exact your holes will be marked.

[Advancedynamix]

Duly noted. Wasn't aware that anyone had tried this before.

I'll be the lab rat for this method. So fa

Yeah, IIRC he used a wheel with dual bolt patterns as his drill guide. I have several sets of drilled drums, but I do them on my mill, and hold the pattern to less than a .001" tolerance to centerline. I then press in extra long arp wheel studs for a Honda civic. I personally prefer the Festiva drums over the aspire drums for weight savings and I like the bias with stock rear drums.

[eurotiva]

I used a dual bolt wheel as my guide. I was very careful, and bolted the hub onto an old spindle, bearings and all. The spindle was bolted to my drill press table. I Made sure it was 50mm from center, and drilled them.

I'll say I won't try it again without a mill. Too much room for error.

[skeeters_keeper]

Listen to these two guys!

If you don't know anyone closer with a mill feel free to swing over to good 'ol Amherst VA and I'd be happy to let you use a mill to re drill all the drums you want.

[Rocketman]

Hmm. What if you made a nice hubcentric aluminum jig, with bronze or steel insert drill guides so there' little or no room for error? I have seen jigs like this before for some 5 lug applications

If you have hubcentric wheels you're in better shape IMO, thats what centers the wheel & carries the bulk of the load.

[sketchman]

Found out some more. The autozone part that shows the correct inside design on the website is not the correct one. Apparently they are all going to the relief-ed inside with bosses, to save money no doubt. Hope I can still find some.

I'm still going to try it at this point. IMHO there is very little room for error using my template. It locates from the stock bolt holes and gives you a center the size of a needle point to punch and drill. I plan to use at least 2 sizes of drill bits to work up to the 10.5mm. I have dual pattern wheels with tires on them I can use to test just one drum before I decide whether to do it to both of them or not. We'll see what happens.